Prospecting, Locating and Valuing Mines: A Practical Treatise

Various · 1913 · Prospecting

How to find, stake, and evaluate mineral prospects. Covers systematic sampling, valuation methods, and US mining law basics.

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The New York Public Library

ASTon, LfNOX AND

tilDcn Foundations R 1915 L

OopiBIORT, 18081, BT

THE suiBiTli'ib Publishing cbiipANY.

Coptbiort, 1903, Bt

THE ENaiNI$iaNG'itN'J3''MlNIN0"Jpj;BNAL.

L latrodactory — Mistakci Id Minisf 1

II. What CoDstitates k Mine. Ifl

m. Rock-foroiing Miaerals ind ElockB

IV, Fbaicat Cbai&cter of Mineni Deposits , . 6Q

V. Origin of Yeina..,,, , 83

VI. ViUmg of MiosTsl Veini!..., , 99

VIL Influence of Rocks OQ Vein Filllfiif. .„„ ISO

VUr. Mineral Depoaita Other tluitt Veina , 138

IX. Prospecting 100

XI. Patents to" Mluing Groaud . .,.., 187

ZIl. E&rly DeTeloTjiieiit IffJ

XIII. Ores. J../..:/.'/.!.-.). 306

XIV. Uaefal Eftrtlir ;Min<?Ii,-iBt.', .V S29

XV, coft] ; !..., 26a

XVL OoldQriTelDepoBitB.,. , .,,.. 971

XVIL Water and Its Meuarement. 803

XVIII. Arteaiaji Wella. - 810

DBefalTablM...,,... B16

Good Books of Reference.,

Plates 1 to 16 iQcluaiTe ,.., 3i4

iDdex.. , 374

J

Prospecting, Locating

..And,.

Valuing Mines,

CHAPTEK L IKTRODUOTORT— MISTAKES IN MmiNG.

-(he foUowing pag€s are not intended for those who hii.<re deToted a lifetime to mining and are educated in thuniany branches of JcDowlede'v-'hich go to iDfike the euccesaf ul mining man, but for those who would like to iDvet a portion of tlieir capital in the busijiese if they felt anfe in bo doiog; and who 'hack becauae of [ their oompletfligsforar.flM of tbefiL.bg*ot; and to restrain the over-eangaiii. .teapfiraments of others, by pointiug out the elementB whicji Loay militate against suoceaB. At the eatoe time k is, -fllived'thattba prospector will also find hiuts whifilL-wi]: hEin in his % 'jariaome labors, enable bitu t;4*i]ialEe'biA'Io£atioQ9 to better ad- vantage than in nbw the case in a vei-y Ini'ise proportion of tho&e on record, and furnish him with the language iu be can intelligently desoribe to others what I he has found, bo that they shall see it just as be does, nod be able to verify hia statements upon inspection. It ia hoped that the explanations and suggestiona , wilt, to some extent at least, prevent him from apend- ting time and money on alueles prospects or worthless 'mineraln; furnifb bim with the njeans to debermiua approxintately the Y&lue of what he has found, and

s

PROSPECTING Ayn VAL UING MINES,

sliow him the way to develop it at the least ©ipendi- ture of tiuas and labor; and enalils bim to see clearly what nature has done to bis advantage, or the obstacles whieb have been thrown in his way.

It ia not pretended tbat new geological fAcie have been presented. Kearly all of tbam can be found in the booliiB, but they ere scattered through many and often eipensiTB works, and in but few caaea ia there any allusion to the practioal bearing of these facta on thfi lutereS'tB of the miner, except in the case of coal mining, which bias a complete and extensive literature of its own. In all these works, geology, in its relatioa to ooal mining, receives full attention but ib Las beea otberwiae with vein mining for the precioua metalB. Where it would be impOBaibletoputthe subject matter iato better language, the writer has quoted freely from recognized autboritiee, and has used some illuBtrationa which may almost be called coromon property from the ffftiuency with which they have been copied by one writer after auotherj but a ]arg;e projiortion of the illustrations are drawn from the writer's own note

The object of ilife Jmc'-.mbifi 'bEsfcrillaBtrated by a few words on £liV c'iiim'ea*of fftifucii/ -mining enter- prises which it is sdtifeht atfjoid; by calling special attention thereto. In' .'ra,fa"t!rniti3e' : buainefis, failures arise from undue '-c*injp(ititi- depression in trade wrong seleotion ofrlooptlouy. oi capital, Mok of buBiuesB tact, want of knowledge uf the trade, ete. In gold mining, and to a certain extent in silver mining, we get rid of the element of competition; and in gold mining, at lea.'st, depreasion tn trade does not aSect otherwise than aa a atiranlua, but all other cnusea operate in very much the game manner both in mining and trnde.

It should be kept in mind that every pound of ore taken from a mine leaves just tbat much lesa in it, and that the end must inevitably oome at some time. Id

mTRODUUTOUY.

this respect a zdiilq differs esaectially from a mercan- tile business wbicli can onlarge its field of operationa year after year as population JDcreaBes or facilities of CO mmTini cation are improved. If the tnine only yields, above working expen&ee, A sum sufficient to repay the cost of tba ground, developmeui and plant, the investor miglit juBt as weli have buried Li dolJtirs for tbe aume period of time, ami saved labor and mental strain. Tbis state of affairs may easily occur even when the mine has rich ore in eight- It takes just as deep a shaft to open a piece of ground 600 ft. loug as if it wei'e 2,000, but tbe cost of sinking and puraping, audi all espenses of corporate managenient wiJl be four times as great per square foot of area developeii in one case as in tlie other, and tbia difEerencB may do awsy Tvitla tbe poBsibility of dividends or even the recovery of the invested capital. Numerous cases of this kind have been seen in Colo- rado and elsBwhere, where snoall properties wLich ODuld not stand the burdens thus impoeed upon them have proved successful when consolidated, one shaft answering for a much larger property, thus saving the cost of constant HinkJut;;, tbe espenaa of. numerotis engines and surface hands, as well as Buperintendeuce and offiae e:xppnses.

On the o&her hand an enterprise mny have so much {ground that the energies of the company are scattered over too large an area, one unproductive section eat- ing up the profits of the better ground, thus lendini; to €onetftufc embarraanment; and a failure under these ctrcnnoi stances may do as much to blast tbe reputation of a di&trict as if the property had been absolutely baiTen throughout

This condition of the mine as regaida its capital renders it uDdesirable, if not dangerous, to experiment with new processes of reduction. So many of these, while enjinentb' succesaful in the laboratory, when worked on a small scale and by enthusiasts thoroughly

Pbospeoting And Valutn& Mihes.

poated on all the minute details ha-ve proved bo inap- plicable on a large Bcale "when operated lees careful men, that a mine cannot afford to employ tliem until they have proved entirely satisfactory under all similar working conditions. The cost of the experimentB sliauld be borne by the projectors of the innorations; all that a mine dare do is to pay a royalty or purchase the machinery when it is no longer an esperiujent. It i% true that the intproved nmcbinerj, bo called might b© a real improvement and a desirable acquiai- tioUj bnt on the other hand if a failure, it would be only another tax on a treasury hich has already its full shore of burdenH.

Again, the price giveu for a mine may be so eiorbi- tant or out of proportion to its development, that while it may pay dividenda for a time and apparently be a succesa, the ore body may "peter out" before the purchase price has been returned in the Bhapeof divi- denda; and failure will ecue, unless a reserve fund baa been set aside, with which to search for other ore bodies. The dispiopoitionote profits of the middlemen or promoters emphanize thig piopOBitiou, as in the ease of the Eiohmcmd tyonsolidated mine in Kevada, which IB eaid to have cost the Btockbolders $1,376,000 while the vendors received about $280000, leaving the promoters a clean profit of over a million dollars. Luckily the miue repaid this enormous purchase price, but had it not, it would have been condemned as a failure, when it was not legitimately entitled to be saddled with fio great a burden. This was etricfcly gambling, not mining. The same thing has happened in floating the mines of many other districts, and notably go in the case of the Transvaal — naualJy with a less fortunate outcome,

A common cause of failure is in not keeping the development of the m ine ahead of its current necessitjea. Such work will naturally reduce the dividends for a time, but it la far preferable to pay

XNTRODUCl'ORT.

tor thess dveLopmeiits out of the profits of the mine, while it is prosperous, than to hRe to raise ai> asss- ment for the purpose when it is looking poor. Those wbo have tried the latter plau know the attendant difficuUies, whieh are eepeciaUy conspicuous in the case of tutoes re]>rese£ited by UDasaegsahle stock. To Bucb mines au empty treasury means ulmoit inevi- tablti death, although a little medieiue iu the shape oi coin, might give them a long lease of life- It always happens that there are eome stockholders who will not advance any more capital, and the rest do not feel inclined to do so and allow the non-paj'ees to come in and reap the benefits; while there is no vtay in which undesirable partners like the non-paying stock- holders can be got rid of, except by foreclosure of a judgment for an indebtedness of the property.

Another freciuent source of lost money is the erec- tion of roiUs or other reduction works before they are required. Nevada is full of illustrations of this kind of folly, which is more apt to be committed by com- paniee than by individuals. In many cases magnifi cent mills were erected before the mine had been opened even au£5ciently to know if there was a niine at all, and never dropped a stamp. Some of these enter- prises were unmitigated swindles and seriously hurt our mining interests abroad, ao that the recovery of confidence took years to complete. Not a few of these mills were also utterly unauited to the ore of the dis- trict and were consequently valueless even fur custom use on the ore of other mines. In other cases the mills have been too krge for the property for which they were erected, and it has been impossible to keep them running steadily — to their injury, as machinery deteriorates rapidly from idleness. It would seem that few miners have any idea of the amount of ore which even a lO-stamp mill will consume in a year. We often hear that a mine is ready for a mill, when it has only a shaft from 50 to 100 ft. deep, or a tunnel of

pRoaPEGTmo AND VALuma Mmm.

the Biime length. The absurdity of this proposition apparent. There may of coui'se be instanceB where the outorop ia so continuously in ore that there can be DO doubt of our ability to put the inioe iu ebupe for extraction duriug the time consumed in the erection of a mill, but this is quite esceptionul!.

Serious troubles hav& also arisonfrom false expeota tioaa based on small quantities of rich ore, or rather of naiTOW Beams. If these coulJ be taken out by them- selves they would often pay haodaomely, even when the quantities would nut warrant the erection of a miill, but as they cannot be extracted without removing a large quautity of ivuate, the coat of doing: this ba3 to be taken into consideration, as well aa the difficulty of preventing the loss of ore by mixture with the waate, eveu when carefully band-sorted. It is not intended to intimate that these very small Yeins or eeams may not be worth working, for aeama of very diminutive thiokneSB are worked at the mines at Nagyag in Tran- sylvania; and in some eaaes, as tho native silver mines of Batopilaa in Mexico, the sheet of ore ia bo tough that when less than an inch in thioknesa it may be left standing while the drift is run alongside, and stripped down once a week or oftener, aa maybe desirable The object is to cull attention to the frequent excessive coet of ivorkiug vary narrow ore seama, that due allowance may be made and failure avoided.

Want of knowledtj;e of the structure of the deposit is often a source of costly errore. It is not many years ago that the writer saw a summer's work thrown away by a superintendent losing the vein and not knowing how to tiud it again, ttarting on the vein he apparently mihtook the bedding of the rock for the wall, as shown in pi. G., £1. 2, and on reaching the point Bj where the ore apparently pinched out, went off into the country rock along a small seam in the hanging wall S. Kot Jdnding the large ore body which was known by its outcrop to exist ahead of the tunnel

Introductory.

he crosscut in the wrong direction at A towRrd C, when finding another siuall Beam he turded back on that toward the main vein again. Had he eontiDued on the line *'I C he would have come out to diiylisht in a direction exactly opposite tt> that in which he eLould have suuht the ore body. The tunnel was run in hard granite under very adverse Gircumatances, eutailiDg u serious outlay of ruoney, which must be charged against any future proJits, because whatever is peut ou a niiae ouy;ht to cou:ie out of it and fit the end of the seaeoii'e worli the property was in a Jess satiefactory condition than before the tunnel was run; an many observers would naturally come to the cou- oiusion that the mine uaa practically wortblees, if the ore seen on the surface wna lost bo promptly in deJth. (It has since been satisfaotorily opeised in the right direction.) The same amount of money properly ex- pended under judicious management would have taken the tunnel through a body of ore which crops continu- ouely for several hundred feet and would have been extracting ore for its entire length, thus making a prolit instead of a loss, and putting the mine in shape for stopiug,

A most astonishiiig want of common sense in read- ing the lesBou at the outcrop has cauftid the loss oi much time and money. In the case of the mine shown iu ph 12, lag, G, the outcrop of the vein occupied theilat slope of a valley with a eteep hill to the north, and was scattered over a width of 100 ft. for a conaid- ©rwble distance, but wae not continuous, being broken up into little pattbea uf varying sisse. The oti; was rich, and being stained with the blue and green car- bonates of copper, was very conspicuous by contraat with the tindeilying yellowish limestones. Evidently bUifl vas mistaken far the outcrop of an immense vein tar bed, but a vei'y casual examination showed that the rein was only & thin film between the slates B and Hmestonee L, for the little gulches running north to

PROSPEOTIIfQ AlTD rALXJINQ MINES.

the tuaiu tame had out through the ore iu numei'Oiiia places, in all cEseEi reTealiiitbe iiuderlyiuglimeatojidj and Bbowiiig the true character of the deposit. That it was not understood waa proved by the company running the tunnel Tto cut the vein. This waB started in the foot "wall and beneath lhe eeain> and naturally neTer encountered ore. Had any further proof been wautingj nature bad fumiebfld it, for at the eastern end of the location, the bluffe (overlooking Death Valley Cal, ) broke down perpendicularly for BYeral hundred feet, and bad the vehi been other than it waa it must bavG shown conspicuously on the face of these precipices which it did not. It would seeai that this idea bad never occurred to the purohaBers, who were out of pocket on the traneaction from |100,000 to f 150,000 in purchass moiiey and working extjenees, while another niinin failure was talked about and nothing said of the folly of the investors and man- agera, who would not believe the facts of the case even when they had paid to hnd them out.

Again, it is only recently that a man profesBing to be a mining engineer recommended the exploitation of a bed of bog iron ore, when a casual investigatioD showed that it was a deposit now forming, only a few irtcbes thick, limited to a few acres of marshy ground, *nd did not show a few hundred feet to the westward, where the ground breaks down abruptly in a bluff to the seashore, consisting; entirely of unconsolidated sand and gravel. Investors in such a Bcherae would have faced certain failure from the start, and would unanimously have cotidemtied minixig a buBiueKH.

Another method of losing money is to sink or bore for metals, coal or oil, or any otbfir enbetance occur- ring in beds or bedded veins, when nature has told the whole story on the upturned edges of the rocks, aa shown in ph i, fig. 4, and pi. 3, fig. 5. In pi. 4, fig. 4, a shaft sunk at D would disclose no toore informa- tion, than could be gained by walking over the country

Introdugtort

tow&rd Bt when tbe obBerver will pass, over q11 tbe rock strata which would be cut in the ebuft, -with an immensely better opportunity of examining them in detail and without cost. If there ia anj'thing of value Bhown, us a coal seam at B, its merits can be discuseed before the expeuditure of a dollar for underground workings and au incline Gould be Bunk on it to greater advanbAge than tbe vertical shaft i>, at least until a full knowledge of ita character had baen obtained. This miatake haa been repeated bo often tbat every person oouuected witb, mining muBt be abltt ta recall instances. The 8ara& might be said of a shaft at B, pi. 3, fig. 5, but at A, in the same figure, a shaft would [be excusable. In tbeneigrhborhood of LeadviUe Colo.,. the writer has seen a proapeotor sinking in tbe pradite to find carbonate of lead ore, which was an abaolutely hopeless undertaking, as can be seen by reference to tbe cross section of the Leadville diatrintj pL 1, ti. 2, whore the granite and ineisa underlie everything and the ore ia associated with the porphyry aud litnastone beds abovo it. The utter improbability of Buccesa would have been appureat to the prospector Lad he possefiBed even a smattering of knowledge of rocka and the occurrence of ore, but his shaft was another mem" ber of the army of failures for want of that knowledge. To him tbe proposition was plain that because others had sunk ahafte and found ore at varying depths, without any surface showing, he had just as good a canoe as thoy. On the other hand the want of the neeesaary preliminary esploration by boring, in the case of coal fields especially (after the presence of coal is known), may entail loss and failure owing to the breaking up of the beds by faults, the presence of which would have been made evident by a proper series of borings in each direction. The beds might not be "faulted" or brokeii so regularly as in tbe idealized cross section on pL fig. which shows a series of "step faults,'" but the figure will illuetrate

PBOSPECTWO AND YALUiNQ MINES.

the general idea. Let B, E, F and ffreprssent bor- ings, n ouly B and have been tDnde, the coal seaiDj repreaented by the hoavy black line would liave been found in eacb> and its dip fairly ascertaindt but no indiuatioD of the faults .4 and B would bave been de- tected, uulesa tho bore hole M had been carried down Bome distance below the coal, and the ivorks for the extraction of coal, based on these borings alone, might be valueless for working the bed between the faults B and G. But if the borings had been extended oTer a larger area and included others at and F, the broken nature of the formation would have been di&cloaed and led to a thorough investiatioa as to whether the laoality could bo proJitably worked, and if not the cost of permanent works would have been avoided. "V'hat has been said of coal applies to many of the gold gravel mines in California aa well.

Even if the quantity and quality of the material, auch as coal iron orSj clay and other minerals,, wbich come into severe competition with each other, and require every facility in the way of cheap labor, cheap transportatioa, and an extended market for suGceoaful produotiou. be all that can be asked, the deposits may be so situated with regard to the latter requirements that commercial failure must result from their explora- tion. Andre, in his treatise on coal Buining, p, 80, puts the case yery clearly :

"But if certain clearly apparent oircumBtancea exist which are sufficient of tbemBBJlTea to show that the undertakings uannot be commercially successful, even if all the other circumstances should prove favorable, it is plain to ordinary common sense that it would be sheer folly to proseo ute a search which in uat necessarily be an expensive one, and which must as necessarily'' end in disappointment. £uormoug aums of money- have been expended in this way to theigreat and mani- fest injury of all legitimate enterprise."

Every mining man can undoubtedly recall numerous

mTRODUCTORY,

coses where labor baa been espended on -worthleBB niinerala which a very slight knowledge of mineralogy "would have saved. Tha writer has seen shaft sunk on a body of black obsidian (voloanio glass), under the belief that it wiw aiitbraeitecoal- Iq another caea the men ivera prcspectiug for coal in a narrow cafion between bauultiu walls, on tbo strength of a few pieoeij of carbonized wood in the gravel beds iilliug the gorge. In another instance several shafts were sunk on a deposit of red jaspery clay carrying specks of iron iiyrite, the prospector mistaking it for ciitnabar OM account of its bright red color, having probably heard that cinnabar was rad, without knowing that usually it assumed thfit brilliant tint only when Bcratcsbiid or pulverized, lor years a prospector in Wasbington spent inotiBy on and clung to the idea that he could develop an iron mine out of a body of clay late mixed with quartz and laro quantities of iron pyrite, not knowing that the sulpbur of tbe pyrite was a most undeBira.ble constituent in iron, an d tbat there was no pro bability of tbe deposit changing its character. Then again tin is an ever- recurring ignia fatuus, Kecently tbe writer was aesureJ in perfect good faith by a pereon willing to prove hiB faith b}' his works (if ho could g:et some one to join bini), that he bad pounded pure tin out of the ore in a conjmon mortar- and another could not bo convinced that the polishing of the mortar while grinding Bo-called tin ore m'rh not a coating of that metal, tbe iron as he called it being 'galTanizedl" Such storiGB lie at the bottom of many a newspaper item, and himdreda of such wild-goose propositions oome before the mining engineer and mining men generally every year. But many a prospector will Bend the beet yeara of his life on such Bchetnes, and not infrequently drag his equally uninformed friends ijito tLem, for want of a little knowledge so easily obtained.

Yet anatber cnnimou Bource of Iobb is the failure to ascEtrtaiii the true Talue of the ore and the probable character and quantity before erecting expensive hoJBtiiig and reduction works. Both of these subiaots are more fully heated of in Chapter II,, and mention of them is here made only to emphasize the iDapor- taoco of extreme care in all these points. Juet as an ounce of quiekBiWer if tloroughiy mixed -with a tan of sand will show ita presence in every pound of the latter on washing, bo a very small amount of free gold will niake a big showmg in a ton of broken white quartz. The writer has seen fl dump on which free gold could be easily found but which gave a return of less than $5 per ton when tnilled. Coarse gold oreSj though the prettiest of specimens, are exceedingly deceptive, and extreme caution is absolutely esaontial to safety. Gold ia so easily extracted from the ore when native (free) that to ask for capital to develop prospects reported to assay $50, $100 and upward per ton IB sure to excite suspicion in the minds of those acquainted with the subject, as with a donkey, a little water, a few pounds of quicksilver, and a faic share of patience and physical etrenttb the owner of such a prospect can create hie own capital, provided always that the asaay represents the whole mass and not some individual specimen.

Costly miatakea are also made through want of knowledge of the way in which ore ia distributed through the vein. Experience has taught the writer that not a small proportion of those who miEht besup- poaed to be somewhat familiar with the subject imagine that a vein has a uniform thickness like a plank, and like the latter is made up of the same material throughout, ao that there ought to be only two kinds of veins, thoaa which never carry ore and those which are continually in ore. Excessive antici- pations and undue depression result from such views a diminution in thickness being never looked for on

wn vctorTT

the ona hand or an increaeed quantity on the other. Probably no vein carries ore from wall to wall through- out ita entire length. The probabiltiea are altogether ag&inst euch a condition. The spotted character of moat ore bodiea is well ahown in pi. B, 'which is a oopy of a longitudinal aecttou of the Bolcoatb mine (Bonaetimes oaUed Wheal Dolooath) in Cornwall, Eng- land. The length on the vein covered by the aeotiiJii ie about 3,300 ft. and tbe depth about 2,300 ft. The longitudinal elevation of the Comstook lode prepared by the writer for the U. S. Geological Survey shows vastly greater blant apacea. A want of knowl- edge of how ore occura in veins has ruined many a mine. Intimately connected with this subject, which is treated at length when speaking: of the structure of veins is the change in tbe oharaoter of ore in depth from varioua causes, frequently resulting in the aban- donment of the mine on reaching the water level. Free gold ores may cbaoge into iron pyrites of a much lower grade, yet more costly to work, and ricb copper ores may give out entirely, being replaced by lo'W- grade iron pyrifce carrying a small percentage of copper too lean to pay the cost of working.

Failure may also occur from want of care in protect- ing the interior workitige, resulting in extensive caves which may involve the loss of a shaft or an entire ore body by mixing it with waate from the walls and reducing its value below the limit of proHtable extrac- tion. £von ouliBide of coal mining aucb accidents are far from infrequent. Only thoae who have aeen the evidence of theimtuenee power developed by the pres- sure of large masses of earth, or even by its eipaneion tinder some circumstances, can realize ita amount or extent. Both in ooal and gold gravel mining tbe floor of a drift is apt to rise up or "creep," from the pres- sure of the surrounding mass aqueezing the bottom upward into the apace made vacant by the drift or tunnel. This occurs especially when the floor is soft

pnospEcrmG and yAtmnfG mines.

(or as tho gravel miners say, 'oheeay"). In one in- Bt&ooe in California the writer has Been a tuDDel driven through tbe riiu, or bed rock of a gravel chan- nel, as might be the lower tunnel in pi. 11, fig. 2, -which, when it broke through into the chaQnel encountered a body of clay and gravel, so soft that it was squeezed by the weiyiht above into the tunnel likB a huge sau- sage, nearly as fast it could be removed. In another case of a tanael being driven to reach some old work- ings, the miners were furnished with a grade-gauge hy wliich to lay the track, so that with one end laid upon the uldar portian, the new silla could be pub in as tha- tunnel progressed, on the correct slope to connect with the old workings. Owing to the creeping of the bottom during the progress of the work, each setof track timbers as it was laid waa aqnecEed iipwofd before the time came to lay the followiug section, an the tuntiel came out mucb tou hih, and was a failure in eonseQiieuQe of thua haviu acquired too steep a grade.

Finally, litigotiou resulting from defective locations ia a fruitful aource of trouble, involving a heavy ta 3; on the resources of the mine. Through a forgetful- ness of the irapoi'tatice of tloteriuining the direction o£ lode before making the location it sometimee happens that the lode paeseB out of the side lines into the prop- erty of adjacent owners, instead of estendiag the fuU length of the claim, and the mine not only lofaes a con- siderable length of the lode, but becomes involved in vesalioua questions of bouodary lines, the litigation over v?hieb may absorb all the revenues or even leave the mine in debt.

Such are of the Causes which lead to failure of mining enterprises. They will be fteen to bo generally due to want of knowledge on the part of the prospec- tor, inTestor and managers of the enterprises of some special point in their respective oapBcities. It must not, however, be understood that all failures result

mTEODuaTonr.

from this cause. There are cases where circumetancea arise TThich eould not possibly be foreseen and guarded atjftinet, and the judgment of the -very best men may err for we are DOne of us idfallible; but it is desired to show that at least very jreat losses misht be avoided if there were a more general uaderBtaudiDg and appre- ciation of the fact that to a Buecessful mining man reqiiirBB a oombinRtioQ of mental and pbyiical quali- ties Buch as few other callings demand ; and that min- iti is a business calling for special training just as certainly as tecbnitial knowledge is essential to the Tvatt-bmaker or shipbuilder.

The present chapter has been practically a presenta- tion of failure after failure, and the&e would he often laughable if the incidents were not so pathetic. The good faith of the men who made tlio mistakes quoted as sncnijles vfun unquestionable, and only intensities tba pity felt for their misdirected energies. Fortu- nately there is a brighter side. The presentation has only been made out of abundant precaution. There is no more fascinating occupation in the world than min- ing; none that Izeepa all the faculties so fully aliTe, and no sensation so pltjasant as the handling of the bullion after a successful run! — while it is not unlikely that the percentages of successes would proye as great aa in most of the other great industries.

CHAPTEE n.

What Constitutes A Mine.

A MERE bunch of ore will not make a min; and it may be well to examine the fflctore -which really go to coDBtitnte a mine. A ''mine/' tben, is any depaeit of mineral which can be -workeil at a profit; that is to say, before the deposit lA eibausted it must have re- turned to the "adventurers" (as the owners or operators are frequently called iu EngJand) the original pur- chaae money, tbe entire cost of the improvements of every nature, and the entire cost of working the ore, -whether it be mining milling, smelting, tracaporta- tion suppHos, superintend euoe, or ofhce epesseSj totcetber i'ith a fair interest on the money invested. If we charge against the salable product all the es- pensea except purcbaae money and plants we arrive at the running cost of production per ton, and if tbe selling price per ton be greater than tbia, the differ- ence per ton will go to tbe accouiitof purcbaas money, development and plant; and there must be in the deposit at least a Bufficifiut number of tons of ore, which, multiplied by the profit per ton, will extin- guish tbe original coat of mine and improvements, it being suppoBed repairs to reduction or hoisting works, etc., are charged to the cost of produciflg and milling or smelting the ore.

For instance, if the purchase -money and original plant cotit f200,000, and the profit per ton over ex - peneBB of production and reduction in $10 per ton, tlie Biine must produce 20000 tona, at least, before it can

What Constitutes A Mins. 17

be alletl self-stistaiuiQ, and a aurplus OTr that niuouut to cover reasouuble interest. If tlie ore be free gold quartz, or free-millmg silver, about 13 ou. ft. in place will -weigh 1 tun of 2,000 lb., go tbat the cubic contents of the 20,000 tons ivould be 2GO,000 cu. ft, equal to a block of ground —

S&Cl ft. deep by 1000 fL long, it tho vnin he 1 Tt. thick. 130 ft. dwp br JfhW ft. lonR- if tha vein be a fl. thick. 65 ft. deep by IIXK) ft. long, if the ?Iq be 4 tt. thick.

or, if the ore deposit be only 500 ft. in length —

BfiO ft. dep by 50& fr, lonfr, if the vein bf 1 f t. thick, BBfl ft. daep by SfK> ft. Ions, if tlm vela be 3 ft. thick. 180 ft, dp by 500 ft long, if Clie vein be 4 ft, tMcIc,

but if the ore ahoot be only 100 ft in length —

S.600 fL deep by ft. Icmg, If the vein be 1 ft. thick.

1,300 n. d*ep liy lOrt ft. ]oiiff, if tiw veio be 2 ft. thick.

a&Olt. deep by lUOft. ]gug, il the veio bt.*4 ft. tiiick.

From the foregoing it is evident that the length of the ore body is of imuienBe impprtancej aa the cost of working a miue increasee with depth at a constantly JacreaBing rate; and the longer the ore shoot, the shallower will be the workings to acGompliBh the same reaulta. If the shoot be only 100 ft. long it will be necessary to sink ten times as deep, at a heavy ei- penae, as if it were 1,000 ft. Of course this is asBuna- iug a theoretical Jfegularity of deposit.

In order that similar calculations may be made on other claaaea of ore, the following table gives the specific gravity of the principal Euetala and their priQ' cipul ores; the weight of 1 cu. ft. of eich, and the number of cubic feet which will equal a ton of 2,000 lb* As the specific gravities of the ores are taken from pure apeaimenB, generally crystallized, they will giva, as a rule quantitiea too small in the column of cubic feet per ton, as the ores in run-of-mine are seldom free from impurities; so that a somewhat

PROSPSiOTlNG AD YALUING MINES.

i;eater number of feet sbould be aBBumed id making the <:alcii1atioD, to be on tbe safe Bide :

BPECIFia GBATITIES OF META.LB AND MIWEKALS.

MctiUs anrl MlnereiLs.

Oold -

mivu'r, free ores

CoppPP

Copl'WT pyrite -

Coyjier, purple ,

CopphT, irray

Cm4ifr silloau.

Qiii<it;siLTer...

CiiEiir.ki&r

Leiid -

Lead, carbotmte -

Ziucblende.

Ztiic, cojtiDtiate.B

Zinc sLlicate

Iron, cost.

iTQUt wroiiglit

Iran, hematite

Irao, ]imaiill6 , ,

IroD pyrit

Irun, iirsixbii pypite.

Iran, chrome

Tin..,

Tfaoxids

AnUcnoDy

ADtimony sulphlda. , .

Quart2

Huorepur —

Sulphate of bairta... . Water

Speciflo GTSvity.

Raage.

is.eo-i9.8a

lO.JO-lJ.lO 6.ai-7-M

"4,'l(M,3b"' 4,40.5.50 4.5G-5.10

""fteT.TO""

a", '904.20'

4.01)4. IS 8.4S-a.49

4,5.30 6, 00.11. 40 4.3a-4.49

6,'*i-7.Vo '

" 4.*4'.6Sl"

'3*.'oi-S.as'

ATcnuje.

19. So

e.ofl

8,S4 4. So 2. So

13.. W S.Oo

7.m

6.M

4,eo

S. E.OO 0,20 6, 75 6,70 S.63 a. 18 1.0ft

Wtiptit or

cubic ft. PouudjB.

jaw.sa

65$.% SRO.OO B53.&1 312. 6fJ SiO.fM

isr.B) sijs.rio

4fi8.75 437.au

sse.ss

4GD.0O BOfi.a.t BIS. 50 27..62 41H.O0 £!8&.6S IBS .03 19S.75 3tll.a7 62.S0

Number of

cubic feet

to ton.

!.66 a. 06 £1,86 3. as 7.6a B.-IO- C.W

2.se

2.ft0 4.S7

e.aa

7.S1 7.BB 8.4a

7, Off

la.fle

10. Os 7,01

But as ive may frequently want the weight and bulk of ores made up of several minerals, tbe following ex- amples will alio-w how the weight per cubic foot of such ores may be obtained :

Cahulation by Hulk. — Take an ore oontaining eay 50% of ita bult in galena, 25% io arsecioal pyrite, 8% in ziucblende, and 17% in quartz. By reference to tbe foregoing table T;'e have :

What Constitutes A Mfnk

0.60 of 1 cu. ft. of Kalena S3i.S7 lb.

o.asef 1 cu. ft. ofaiTjenieaipTrrte ii.881i?.

O.CS ol 1 cu. ft. of zinc bletuda 20.60 lb.

0.17of lcu,tt. Of quirtH - ffl..

I. no 3TB,901b.

CfdeulatJon b'j Wej'ghL — But jf it be desired to ascertain the weiglit of 1 cu. ft. of ore containiug' tlie Bftiue luiuerals estiiimtQd by weight insteiiii of buJk, we can calculate the bulk of a knawa definito weight, aay 1,000 lb., and instautly determine tlio Tveitrlit of 1 cu. ft. by simple proportion. Out of tbe 1,000 lb, we ahall have:

500 lb. gaiena 408.75 l.OBS m. ft.

aw Hi, nrwuk'til pyrite S87.rifp O.iMScu. ft.

80 lb. ziucbh'TiilB — S.IB.iS 312 cu. ft.

170 lb. quisrUi 1I56.1S - i.im cu. ft.

1K

S.C61 cu. n.

or 6.102 ou. ft. per ton. By proportion the

Gal€Tia 0,350 of 1 cu. ft x 458.71! 181.08 lb,

Af.';eDica5 pyrite 0.213 of l cu. ft. x 3ffr.60 - H2.15 111. Zincblenda OAOSi of 1 cu, ft. x aM.as 2H.14 lb.

Quartz o,33(i i>E i ca. ft, x ififi-fra fl5.oa 1&,

1,000

83a,W)

K

B AU other oambinatiDnB may be worked out by thsBe exainplea. Assuming the profit on this claea of ore to be thai same aa that of tlie free gold ore given pre- viouBly ($10 per ton), it is clear that the ore body flrouid only hnve to be about 1)hU' the dimotisiona before quoted to secure the same reenita, &s 1 ton only oo-

cupiee about half the space of the l!irst illustration. Favorable Conditio tui,— If the m'me is so located that ita product can be aold to independent reduction works, it is jilain that einaller ore bodies niity bo profit- ably extracted; and yet smaller ones if the mine be worked by the origiujil discoverers, and the ore is of a grade high enough to yield a margin of profit over the cost of o:sttactio]i aud trauaportation to market, as in the first case Ujere are no reduction works to be paid "or out of the profits of the mine, and in the latter

PROSPEGTINQ A2?D VALUIIfG MINES

case, neither reduction works nor purchaso money. Any oi'6 body fulfilling these conditioua may properly be caUed a mine, and it is such tba the prospector is looking for.

Mrning Covipared xcUh other Busineas.- — Only an exceedingly small proportion of the locations made ever develop into mines, probably n,ot more than one in a hundred. On the Comstouk lode, out of several thousand louationa on record, leas than fifty had any large amount of development, and still fewer ever paid dividends i yi the gi'osa product of bullion from the comparatively few active mines was enorjuona. Simi- lar oonditioij& hold good m most other mining campe; but it is likely that the percentage of success in min ing enterprises is fully as great as in almost any other lino of buainess — certainly ay great if the same amount of care haa been exercised in selecting the property as ia usual in opening a new stora or hotel. But the miner muefc always remember that while the businees of tha store may expand indefinitely, he ia from the very start living on his capital (the totai amount of ore in the mine), and that this dimioisheB daily the more rapidly as the output is enlarged ; while after reach- ing its extreme rLoductiveness the later stages of a mine are merely like realizing oq the assets of a fail- ing bueiuess.

YALnATTON OF MrsiMQ Pbopertv. — The value of min- ing property is therefore not to be estimated by the amount of the dividends it maj' be paying at any par- ticular time, but by the number and value of the divi- dends it will be iihle to pay in the future.

Eflalion of Profdn to irt'ce. -Tbua, because a mine has just paid an annual dividend of $1,000,000, it does not follow that the mine ig to be valued at $10,000,000 (which would make the dividend equal to J0%}, because it can only bo worth that figure to pur- chasers for investment if it is able to disburse that amount or over in dividends in the future with a fair

WHAT COIfSTITUTSS A UWn.

iDterest on the iuTestment in addition. If the ditri- deiids were distfibuted over tea yeari at the rate of $1,000,000 per annum, the mvestora would juat reteive tha original amount paid without IntereBt so that if the inveatore ar© to receive interest at the rate of 10%" on the money invested, the mine muat paj' another $5,500,000 in dividends, making ¥15,500,000 in all, to be worth $10,000,000 aa an investment.

But it might ho that the mine had reached its maxi- mum prod uotiveu ess when it paid the million- dollar dividend, and the ore bodies in sight began to show fiigns of exhaustion. In euch a case the extreme value to an investor would only be the actual profit on the exposed reserves, which mi;bt be small.

The chance of finding new ore bodies cannot be expressed in iSgures. One of the great sources of dis appointment in mining enterprises ia the over-eatima- tioD of mining values, mistaking capital for proht. Another i% the payment of unjuetifiable prices, not only for properties with considerable development, but for holes in the ground or more naked locations. It is true that very often the purchaser expects to sell again at a profit and not to work the property, but then ha has removed hia dealings from Mining to the realms of Speculation and has no reason to grumble if failure follows the chauge.

Ore "in Sight." — Practically the value of a mining location is the net profit on the ore exposed. If there is any promise in the surroundings of a future to the locahioG, this definition miht possibly be enlarged to the gross value, the purchaser looking to developments made with hie own capital for reimbursement of the original investiueut and profit. The value then of the majority of original locations ia very smalL Many of them are absolutely valueless, being made upon amere etain or a slight difference in the color of a certain streak or layer of rock, or the preafiace of a little iron pyrite in a particular seam, which only means that

PROSPBCTINQ AND VALXrWO MINES.

there has been d&cocaposition of gome of tbe horn- blende or allied mineral contained therein. If how- ever, there is actually yaluable ore in eight, tbid mu&t be oarefuUy measured for length and breadth and if these maaauremnts show a contiunous workable body tho price of the location might posaibly be the value of this ore to a deiith of a few feet, according to the width of the ore exposed.

The ftitnatioD is improved by the sinking of a shaft or the running of a tunnel, but a single shaft does not prove the esistence of much ore. It simply ebowa ita preaence at that particular point to a certain depth and the Quantity Jn sig:ht will be the two tiiangies a and h in pi. 13, fig. 1, multiplied by the average thick- nees. If t'wo shafts have been eunk, aa in pi- 13, fig. % we can call the shaded portion 'in sight." Xf tbe development be a shaft with drift from the bottom, as in pi. 13, lig. 3, we can still only consider in sight tbe portion shaded, with a probability of more because of the ore in the bottom of the drift c. The same will be the case if a tunnel is run on the vein as B in pi. 13j, tig. 4f but if the bottom of the shaft A is in ore and tbe face of tbe tunnel B also, part of the block D may be added to tbe probable reserves (unless tbe ore is growing amaUer in width), though it cannot be con- sidered actually in sight, by which pe understand a block of ground exposed on all Bides, aa in pi. 13, £g. 5, where the blocks E E &t:& actually in sight and DDD can be added as probabilities, along with an unknown quantity below the lower drift at P. In all the foregoing examples it is supposed that the outcrop is tbe e!£tren:ie workable length of tbe ore and that none of the underground workings have been run out of ore, so that we hove no means of judging whether the ore body is holding itg own in size, or increajsing or diminishing; but if the exploratians have developed the facts abown in pi. 13, fig. 6, we can a£ford to be liberal in the eatimate of the probable reserves, as dis-

Wbat Constitutes A Mine.

tinguisbed from ore in sight (shaded), baauae U iB evident that the ore body ia not at preeeut diiuiziiBb- ing in horizontal lengthy and may therefore be exten- sive in depth. If, on the oontrary, the result has bean fts ehowDio pi, IS, fig, 7, we mu&t be exceedingly con* servative, as tb ore body is evidently pinching out downward as well as laterally.

It would be easy to estend these lUustrationB, but enough baa been eaid to show the basis on which eeti- mates of quantity of ore in sight in a mine are oi'rived at, and fllao to show that work is the 0£i]y biog which can give vaJue to a iMation. Because a prospector has been able to make two or three locations or more, in a seaeou's work, it does not follow that they are actually vporth the time epent in securing tbem. The value of an article is not the price paid for it, or its actual cost to the owner. The price paid may have been out of all proportion to the value or the actual cost of the article may have been so reduced by improved tua- chinery that it can be bought for a jnere fraction of the eum paiii for the original production. So the value of a uiiniug property is not to be estimated by what it hfis cost the parties offering it for fiale but by the profit it will realize to the purchaeer.

Grade of Ore. — But even a large body of ore niay be valueless if the cost of extraction aad reduction equal or exceed the value of the metal extracted from the ore; nor does it follow that, because ore of a certain grade has been profitably worked in one mining camp this will hold good for all others, as the conditions vary so widely. If everything in the shape of sur- roundings is favorable, a very low-grade ore may prob- ftbly yield a profit, while in another camp a much richer ore may bring the miners into debt.

Sampling, — Where no work has been done on a loca- tion which ehowa enough of an outcrop to justify a more extended examination we can simply sample the croppingB thoroughly to ascertain which portions of

Prospecting And Valuing Mines.

them flarry miperal enough to be valuable, and the ctharaoter of thie mineral because it is seldom that the outcrop is of uoiforu] value throughout ita leDgth This ie not done by taking band Bamples hero and there, for the most honest man ia not honest enough to be abla to select a fair average in auoh a way. A cleflQ cut across the entire width of the pay atrsak abonld be taken at stated intervale, to avoid the interferenQB of the judgment or the deception of tbe eye, and each cf these ssimplea should be thoroughly broken on a olean door, mised, spread out in a thin sheet and quartered. One of theBo quartere ehould be broken still ifiner, remixed and again quartered- This yrill probably bring tbe eacaple down to such a size that its entire maB can be ground to coarse "pulp."

Assaying. — From this pulp samples should be fur- Dished to two independent assay ers, retaining the balance for further teats should there be much diSer- ence between the results obtained from the assayera (between whom there can be no collusion, as the look of the puilp will not betray any peculiar external char- acters of the ore by -which its identity might have been suspected). To furnish both assayera with the same pulp is also fairer to the aa&ayera, because they are both, placed on the aame footing which ia not the caae when a piece of ore is broken into two pieces and onehatf given to each (except in a few exceptional casee) as there may be sufficient difference in the composition of the two pieces, especially in a complex ore, to war- rant considerable discrepancies in the results obtained, which would naturally throw a shadow of doubt upon the entire invaatigation. In gold ores thia ia very liable to be the caae. A small sprinkling of telluride of gold (looking like lead) might run one specimen up into the thousands per ton and the other give only tens. Care eliould be taken to distinguish between mere epeoimens and true average samples.

In thia way only coii reliable results be obtained.

WHAT COHrSTITUTES A MINE.

S5

but if tbo ore prove to carry munh gold, even then they will not be entirely aatiefttctoiy, nor will they indicate fcli ti'US commcfoial value of the ore uule&B deterniinaticm of the nature and quantity- of undesir- able mineral conatituenta be made, if such are sus- pected from examiaation of the ore as taken from the

Whan gold is found only in combination with other minerals it is usually disseminated thi'ougb then* in siioh fine particles tbat the di&tribution is compara- tively uniform and an assay "will be Batisfactary, in mi far as the amount of gold in the ore is caucerned; but* when a portion of the gold has heooms freOj, or libera ated from the assooiated minerals (as the various forma of pyrites) by the decomposition of the latter, or atill more so when a partioa of it has never been in com- bination, but is scattered through the mass in pai'ticles of varying dimenaiona, the assays will be iu all prob- ability valueless, because itbey may accidentally include quite a large piece of gold (comparatively speaking) and this multiplied by the thousands of times which an assay sample is contained in a ton would give very high results, while the nest sample, not containing such a piece, may only show very small or InsigDiliGant returns. This may easily oeeur, as the gold oanuot readily be ground tine enough to pass through the sieve with the other pulp, but must be mixed with the pulp after it is ground, and thus the chance of getting a fair average aample is eisceediugly small.

Horn Spoon.- — Every prospector should carry a horn spuoQj made by cutting off the belly of a large cow'a horn and polishing the inside with sandpaper, as in pi. 13, fig. S; or he can obtain an iron one of the same shape, but having ouehalf galvanized to better show black ore mineFals- Such a spoon can be carried in the pocket, and if the presence of free old tn the ore be suspected a few minutes will sif&ce to grind up a

2G

Prospectinq Amd Valuing Mines,

sample au a Bjnooth flat rook with a email band Btone, nud wash it out in tlie nearest water iiole, which can be very mucli smaller than is required for the old. paD a bucket or even a wash basin being amply large enough. The very finest colors may be detected by this method. If any are found, a sample large enough to eecure a fair average ebotild be taken, and tbd entire raaaa reduced to pulp. All acreeainga which will not paQS through the sieve ebould be saved until the process is complete, and then returned to the pulp, the weight of which while dry should be carefully ascer- tained. The pulp should then be mixed with water, adding sufficieat quicksilver to umaljamata the free gold, aad thoroughly worked over to insure complete contact of all the gold with the mercury- The amal- gam thus obtained may be reduced to a button with the blowpipe, care being taken not to inhale the mer- cury fumes, and then by simple proportion the amount of free gold per ton may be ascertained with reaaon- able accuracy, if the average of several testa be taken. Thus, if 5 lb. of ore contain 25c., 2,000 lb. will contain

Segregating Ore Miairals. —An assay of the pulp which is left will give the amount of gold in oombinft- tion with the "sulphureta" per ton, and the sum of the two the total value of the ore. Also, by washing out the sand the percentage of sulphides per toa of ore may be ascettaiaed, und an assa* of these couoen'- trated aulpbidea will give the value of the concentrates per ton, and enable us to formulate a plan for their reduction. But if the ore contains a number of min- erals, such as iron pyrite, arsenical pyrite, zincblenJe and galena, we cannot decide on the beat nietbod until we have aacertHinedj by assay of pure Bamplea of each of these mineralB separately, which it ts that contains the gold, or whether it occurs in all of them indis- oriminately.

Id the case of amelting ors, such as galena com-

Wsat Conbtitutes A Mine.

bined with zinoblende, for iustancej the presence of the latter being detrimental to tlie proceBs, it is espec- ially desirable to know whether the blende cairiea any appreciable amoact of the precious metals contained in the ore, &s the diifEereuce in the specific gravity of the galena and blende is so great (7.5 to 4,1) tbt the latter can be easily eejiarated from the former during the process of conoentration, and if valueless except as zinc, might be throwu away as a waste product, or reserved for separate treatment if in suffioient quantity to wai-raut uuh a courae.

If the gold is largely in combination with lion pyrite or other minerale which are easily decompOBed by eipoBure to the action of air and water, the out- crop may yield a good showing of free gold in rusty quartz, stained by the oxide of iron derived from the pyrite, which may suddenly diminish in quantity when the permanent water level of the njne is reached, below which a large portion of the gold may be in. combination vith the unaltered sulphideB, Usually auch gold is very fine, almost if not quite like flour, but occaBionally, as in iron pyrite from the slates near Fiddletown, Cal.j the threads and cryatala of gold may be readily seeu, and felt proiecting from the polished faces of the large cubes.

Special Cases, — In the case of ores containing native copper, the plan of taking a number of pounds and working it in the same manner as free gold is the only practicable way of getting fair results, and the same remark applies to those carrying native or horn silver, in fact to all ores containing minerals which will not pulverize and pass through the sieve; but ordinary aeaays are applicable to all other ores, provided care Las been taken in preparing the samples by having tbem large enough and thoroughly mixedj aa as to secure average results.

Worting Tesl, Mill Huns, etc. — As work pro- resaes the accuracy of the resulU lirst obtained may

PEOBPBGTmG AND VALUING MINES,

he tested to aome extent by actual working metliods. Tbe facility and cheapDSBs with 'wLich tbis may be done depend upon the nearness of reduction -works of a suitable charaoteT, Higb-grade ores can be shipped gver trails on mule-back to works at long distances from tlie mines, and even if tb© expenses conaujne all tliB returna the experiiuent will be worth the cost; but low-grade silver ores cannot be handled in this man- ner.

Aradro,. — In the case of low-grade gold ores, in which the gold is free, hich will not bear transporta- tion for long distances, good working results may be-' obtained from an arastra built on the ground, as it occupies only a small Etpaoe and conaumea but a Bmall amount of water. The aiastra consiats simply of & circular £oor made of large flat rocks carefully laid so as not to leave crevices of too large a size between them, inclosed by a low stone wall auitable height, say 2 to 3 ft. In the center is erected a vertical spindle supported by a cross frame, to which spindle is fastened a long horizontal shaft, and beneath the latter cross arms to which large flat stones ("drags") are fastened by means of short ropes or chains. "When a horse or mule is attached to the long shaft, and driven round in a circle, the cross arms drag the rocks attached to them around, and crush any ore which may be fed into the machine between themselves and the floor. Of course the amount worked daily will depend on the size of the arastra, and the softness or hardness of the ore, but it will do its work well and give a fair working test.

Vtiiiiy of TeetB. — -Ey keeping the ore extracted from each 10, 20, or 30 ft. of the shaft or tunnel by itaelfj and working or shipping the batches separately, the miner will soon learn which portion of the ore body is the richest, and also whether it is fairly uniform in value, or changes frequently within short distances. A few such testa will soon determine the question

Wbat Constitutes A Mine.

m

whether it will pay to huild a road to tbe mine, for the comt of auch a road will ultimately have to ooma out of the luiDe.

Roads. — Without roada no heavy machinery can be gotten to the mine at anytbmg like reasoDable cost. Mining roada are often very costly enterprisea owing to thti rough and brokon nature of tbe country which they muat traversg, and the want of fcbem not iufre- quenfcly greatly retards the development of otherwist) promising: mining diBtriots. Ab all the locations in a new district must; share equally in the baneflta derived from a main road placing them in ready oommunica- tioa with the outBide worlds the cost of the trunk road should be raised by an agsesement on each locatioUj made, by action of the miniug lawa of the district, a rsqujsito to a legal title to the location. The lateral branchea to tbe individual minea would nriturally ba built by the mmes at their own coat. A mine opened by tunnels only will of course juot fee! the necessity of roads ao promptly and keenly aa one whioh ia com- pelled by the nature of the grouud to resort at onoe to shaft-Binking, as the former will be able to get alon with packages which need not exceed a mule-load in weighty except in the artidle of timber but all require the roftde sooner or later as a matter of economy even in provisions and supplies.

PLABfMiBa Eeductios WoflM. — Having then become eatlafied that the ore body its large enough and rich enough to pay for its extraalioDj the character and size of the reduction works remain to be determined.

Smelting. — Should it bo decided that tbe ore will be best reduced by smelting, it is doubtful whether tbe mine would be justified in erecting its own works, unlesa it is situated where purohases of various other ores can ba readily made in conaiderable quantities, aa few mines produce ore which m&y not be worked to greater advantage by admixture with other ores which can supply its deficiencies without adding barren

material to the oharge in the furnaoa'. Ores rioh in gold and silvev, but poor Isftd (usuBiHy calJed "dry" ores), may require rick lead ores to flus properly; or ores with an excess of stHoa (quartz) may require the addition of lime or iron -bearing ores to accompliah the same result. It is from this oircumataiice that the great smelting ceaters, such aa Denver, Swansea, eto., have arisen, which purchase everything which maj' be offered, and mi and work the ores to the best advan- tage; each elaftgof ore being kept separate in the yard, A furnace charge may thus be made up from four or five different kinda of ore, from widely Beparnted locali- ties, the more refractory ores being added in smali quantities to thoae which work mora readily.

Concentration..— -li often, happens in a vein that on one of the walls there may be a atreak of yolid mineral suitable for shipment aa it comes from the mine, with no — or only slight — sorting, while the balance of the vein is filled with material in which there is eo rauob waste as to render this impracticable; or the entire vein may be of this character.

If the distance from the mine to the smelting works is great, and eapeoially if any considerable portion of it be only trail or wagon road, it may not pay to send these poorer ores, as the whole espease including trans* portation might very likely more than equal the prod- uct Such orea must be dressed to better grade hy some method of concentration (usually by waBbing, more rarely by air or magnetio separators) if the re- sulting concentrates are rich enough to bear the cost of tranaportfttion ; otherwise they may be valueless until the conditiong of ti'anaportation are modified. Concentrates consisting largely of galena or heavy sul- phuretted silver ores may go to the smelter, but those made up almost entirely of iron pyrites such as are obtained from many gold ores, may be retained at the mine, and worked by ohlorination, if the daily prod- uct be large enough to keep a fimall reverberatory fur-

Wrat Constitutes A Mine.

nace for roasting in steady operation Tliese pyritoua ores may also be made into a oommGrcial product by tDatta Bmelting.

The capaoity of the concentrator ehoulrl be propor- tioned to the output of the mine, iust as the size of a etatup lain is determineiil by the same factor, and this output will depend on the size of the ore body And tbe condition of the development.

. Ore Supply Needed. — We frequently hear of a mine being ready for a mill when it bne nothing more than a shaft 50 to 100 ft. deep, or a short tunnel on the vein. As an approstmation we may say that a rajae should produce 1 ton of ore daily for each of the men em- ployed around it, including blachBrniths, carpenter;, cannen and outside help. There are of course mines where better than this ie done, but these are excep- tionah We must therefore have room enough in the mine for a conBiderabla number of men to be enfraged in "atoping'' ore and this involves a timber of drifts or stopes, even for a sxnalii juill* If very active deveSop- meiit is going on and the ground is easily worked, there might possibly be Bu£Cient ore extracted from the face of the variouE headingn, sinkings or upraises to keep a amali mill going i but to depend on theae would be bad policy* for the ore in several of them might 'pinch' at the same time, and ehut tbe roill down. Indeed, a mill should not be built until the ore body has been so thoroughly explored that it may be perfectly adapted to the requiremente, both as regards size and character of equipment, as although it may be possible to find tbe money for eiperimenta or mistakes,, they must all ultimately be paid for by tbe mine and diminish the profits.

CaUruiaiion of Tonnage Mined. — To enable the pros- pector or miner to form a quick estimate of the amount of ore which he may be extracting daily from a drifts tbe following table will be found uaeful. Three kinds of ore are given as types. First, prac-

'33

FROaPBOTIUfQ AND VALVlNQ MINE8.

tically clean galena; second, a concentrating ore; and third, ordinary gold quartz ore or free-miUing eilver ore, neither of which carry miiGh heavy mineral. The yield in poundH ia fori running foot of adrift 7 ft. high, and this figure mnltipUed by the number of feet run daily "will give the daily yield in pounds, provid- ing there be no 'ivaste in saving the or, as is usually the case in Email aeams, which are difficult to take out clean, especially if the ore ia brittle or friable.

PAUY OKE ESTBAOTIOH PER BtTHNIMG FOOT; DBIFT 7 FT.

men J vteik tektical.

ClaflH.

Weight

per cubic

foot.

Thlctneaa of Oto.

a in.

Bin.

Sin.

1 ft.

2 ft.

Sft

ifC.

0.J1

]&41 1H8 0.B7 O.Ss

O.&H

0.4U

l..t!4

i.ia n.62

Iss3G S.33

i.ie

4.ftS B.44

13],92 Ihs,

3S8

mai iba.

S .-

4.W tons 464 lbs.

S

The principle used in this table may be applied also to sinking shafts, thug: multiply the areaof the work- ing face (if all ore, otherwise the area of ore aeam only) by the Duniber of feet sunk daily, and this by the weight per cubic foot in the tfible. For instance if we aink 3 ft. daily on a 2-ft. vein and the shaft ie 10 ft. long, then 10 X 2 X 3 X 328 60 cu. ft. X 28 9.84 tons, for ore of the second class; or if a drift be 6 ft. biih on a 2-fl vein and we run 2 ft. daily,, we have 6 X X 2 X 328 24 cu. ft. X 328 3. 93 tons.

To aBsiet Uo in forming an estimate of the most desirable size for a aiill, the net table will be found useful, being applicable also to the required capacity of a floucentrator.

The duty of a stamp varies greatly according to its weight, the height of the drop and the number of drops per minute, the hardness of the ore to be

What 00N8Titute8 A Mine.

orusbed, the fineness of the Boreen through rhicb the pulp must pass to esoape from tlie battery, and the height of the discharge. lu the case of many gold ores, in which tbe metiil is very fine and the rock hardi tots per stamp may be a fair day's work (24 hra.), bufc Tvhea tbe rock is Boftei*, or the gold coarser, it is not ntceasary to uta fio liiia a mesbj and the duty may run up to 2 tona daily ; while if tho wurliing of tbe ore is to be finished by grinding in pans, or the ore ia exaeedingly soft, a mUl may criinb still coarser and pass tons or over under eatih in 24 hra. The table is therefore arranged for each of those three capacities, aud shoivs tie amount of ore crushed an- nually, its contents io cubic feet and the area of tbe vein which would be extracted at various thickoesB. It is based on the ordinary gold quartz or free-milling silver ores (such as tbe ores of the Comstock), and 13 L'u, ft. in the mine are considered to be a ton, as tho reaulfc of determinatious made on that lode; and 300 (Uya actual running time in the year. If the mill runs more steadily the quantities must be propoi'tion- ately increased.

Capacitt Of 4 10-9Tamp Mill.

Clan Ore

s.-

Igq

Oonaiiniiptioii pi;!" die-m.

lona. tons. tone.

SiiO

CoQSiimp, per aaauOL

4,fiO0 Sfi.FiUl

78,100 13.D0O

."jSDOO 7S,0QO

7.SOI3 Tona. ti:,500ou,ft. l."i.00tiToDa. :,500cu,fL

kssjL

Of Vein Estbacted

AirsuiiT.r.T.

Duty of Stamp.

Vein, I ft

Vein, 3 ft.

Vein, a ft.

Vein, 4 fL

ToDi.

FS. GBSxltn

"Ft B92ri0O

n.

lISxiOO 3S5xl00

Ft,

Sh

9:5xl01>

84JEl(n

The mised ore is merely given &e an illiiBtration. Id fact, as a oonoeutratiDg ore, it would iflOfti likely be treated 'with roils or other crushers than with stamps, the object in concentration being to keep the crushed ore in as large grains as possible, as the diffi- culties of coDcentratioD and percentage of loss increftse Tvith the Enenees of the pulp.

The table itself requirea but little oomment- TVhile ma,tTe up for only lO-starnpa it can be modified to apply to any desired number — but it einphaeies very strongly the desirability of long ore bodies au it is evident that to get a year's supply from a tunnel on a vain 1 ft. wide, with a rise of the surface on the hill of 1 ft. in 2, we should have to follow the ore 4S4 ft, into the hill and upwards 242 ft. to the surface at the end of the tunnel, aa in pi. 13, fig. 9. If the ore shoot were only 200 ft. long we should have to siiik on it Of run anothtir tunnel, either course involving an extra amount of dead work. If 100 ft. long; only, we &|jc>uhl have to sink5H5ft,, attaiuing a depth of nearly 2,400 ft. in four years. If 200 ft. lonj;, ws should sink 1,200 ft, iu the Bama time, Ab the cost of sink- ing and working mtiu shafts is the heaviest item in n:]inin, the leugth of the shoot, as before stated, is all importttutn

Backa. — In no case should the outcrop be congid- erod immetJiately available ore. About 50 ft, in depth, or at any rate a tiutBci&nt thickness to avoid caving, which will depend on the width of the vein and the condition of the walla, should be left as a pro- tection to the mine from surface water, for if the ore be extracted it is sure to leave a ciepregsion into which the snow and rainfall will drain, and find their way to the lower workings, to be subsequently pumped out at a heavy cost. These croppinga will always remain an aiailable awet, and ahould be the last thing taken ont of the mine.

Depiuition of a "Mime." — To eum up then, a mine

WHAT COJUSTlTXJTKti A MINE.

is a body of ore of sufficient size and riohneflB to reply all costs of purchase mouey erection of all neceBBarjr plant, tlead wort, extractiOD, trauBportatiou and re- ductiojij with good luterest on the capital. Success will Jepend largely on a thorough knowledge of the aize of the ore body aa regards length, depth and tLickness; the true character and composition of tha ore; the adaptability of the hoisting and roductioa works to the reHiuiremeata of the property; careful tuauaisemeiat by thoroughly competent men well up in the LusiueBs; avoidance of miBtakeB aud experimental severe pruning of all unneoeaaary espeneee, aud the treuttuent of the lutine ah a bubiness undertaking and not as a ganabling piupoaition.

CHAPTER ni.

EOCK-FORMmG MISTBRALS AND ROCKS.

It ia ot propoaed to go further into this subject tliau to fuFniah a coiidenged outline of tbe composi- tioQ uud Btructutd of the pfincLpal kiuda of rooks, those most commoLily met with in couuectioo Tk'ith mineral deposits, bo that the prospector may be able to reuogniize tbe most important of them. To desoribe aU the difEerout variotiea would require a volume and would be of no Bpecifi! benefit in this ooiinection, as the distiuotious are frequently founded on the prea- enoe of Bome minerals of dif&cult reaognition and quite secondai'y importance, and the deBoriptions "would necessitate a much more extensive ibnoivledgo of mineralogy to make them intelligible than it is neQeasary for a miner to possess.

nOCK-FOEMIMa JMHTEBALB.

The principal minerals which make up the bulk of the rock formationa are Tery few, and we shall find that when able to recognize quartz (or silica), feldspar, mioa, hornblende aad angite, there will not be much difficulty in giving a rock a name. Some of these names may really apply to groups of rocks but in eueh cases the name of the group will be olose enough. It is the different ways in which these five miuerals are combined that distinguish the igneous rooks from each other; and it is the predominance of one or the other in the secondary rocta (or those which have been made out of the wear and tear of the igneoua eeries)

BOtJK-FOnSlAtt MINERALS AND R0CK8. 37

whict imparts to thess seooDdary (or GedimeDtary) rocks iaelr peculmr characters.

I Granite oonsiata of quartz, feldspar and mica; sye- nite, of crystallised fedepar and homblemde ; and basftlt of feldspar and augit, ith chrysolite or olmne so tllat ith specimeDB of these three rccke before us, or even in some cases with girauite and basalt only, w<d are ready to study the characters by which the min- erals are to be reoognized. The basalt used for refer- ence should not be so fine-g;rained that its conetitueat minerals are indistingtiiBhable to the unaBsisted eye.

Quartz is the glassy portion of granite which cannot be Bcratched with a knife. It crystallizea m the well- known *orm, the separate cry&fcola being always six- eided ptisms terminating in a rather blunt pyramid with bit: sides or faces; so that the description will be : oiystal'izes in six-sided jtriams (hesftgoual) with sis- sided Dyramid for a termination ; cotor sometimes linge'l with pale smoky or rose color, sometimes violet as io the amethyst, ugujiilly colorless and transparent or ni'iky white; luster, Titraous (glaaay); hardness, cauiaot be scratched with a knife, and itself scratches feldspar, glaaa, etc. ; notacted on by Bul|phuric, nitric or hydrochloric (muriatic) acids.

/'idiiar ia the white portion of granite which can be scratched with a knife. There are numerous Tarie- tiea of feldspar, distiDgoiahed by their having either soda, potash or lime as one of their constituenta in addition to the Eiilioa and alumina which are theessen' tiftl ingredients, but it is not easy tu give differences which would be easily recognizable by the beginner in the study. The crystallized forms are usually white* more or less inclined to be traasparent or trans- lucent in new fractures, but often weathering to a loilky white. The feldspaj-s in granites vary in color from white through pink to dull red and often occur as seams of varying width running through the body uf the rock. These seams are inclined to break into

PEOSPECTmO AND VALUINO MINES.

nquorish fragments, showing the tendency of the crystals of this varioty to have only four sides. In inany of the porphyries almoat the entire mass is feldspar, the hoJy of the rock being a kind of paste of nn crystallized feldspar oolored various ehades of browu, tsreen, piuk, red, and purple, with scattered crystals of white feldspar, or transparent quartz, im- bedded in the paste, giving to it a upotted look. On decomposition of rocks largely composed of feldspar we have a series of clay formatsons, jnet aa granites yield sand and sandstones.

Mica IB the tnineral which in thin plates Is often wrongly called isinglass (ivhioh istishlue). In color it varies from colorless or white to black, through varioue shades of gray, brown, yellow, green and! violet, the oommonest color-s beiioe: white, yellow, dark brown, dart green and black. While sometiniea found in crystals of large size, they usually are quite small- The crystals are Hat, six-dded, and invariably split into extremely thin plates parallel to the base of the crystal. When broken across the crystal, as ia often the case in a rock fracture, the characteristic eis-sided form may not be visible, but the thin plates separate easily into a brushy edge. These plates are elastic and yfln bo bent coDiiderably without break- ing, by "which chftracter the white vartpties of the inin- eral cim be distinguished from the cry&taUized varieties of gypsum, -which are also white and trana]>arent and split into thin plates or laminse, but are brittle and break caaily on bending. They are also destroyed by the action of heat, whereaa mica is practically infusi- ble at ordinary temperatures, and is therefore iised for fttove fronts, etc. When a rock is broken the cryatals may show with the Hat side tip, when they will appear as in a, pi. 13, fig. 14, but if the fracture cuts through the crystal the shape may be like b in the same figure, the edges of the thin plates showing distinctly. The colorless or white mica is called muscovite; the brown or black variety, biotite.

WK-FORMING MINEUALS Al

Horuhhmde ocelli's nsusilly in small crjjstala, jen- erflUy blAck or grecriij&}i blaok. It is Lui-iJier thtio laica and dacB not split iuto tbiri layers, which fact can be determiiied by the use of the knife. It very freijuently cTystallizes in little square columns like q. in pi. 13, fig. 15, and sometimeB in sii-sided crystals, which fflay, however, be easily distinguished from Toicu bj faHTioig tTvo of the opposite sides much wider than the others, as in 6, ph 19, iitr. 1£. Hornblende is not always cryatalUzed. It often occurs in greenish or blaakiBh luasaeB with a fibrous or radiated structure, sometimes formiug a rock almost by itself (horn- blende rook) and grndee dowu into aabestos, which haa practically the same coMjpoeition, atid is only one of the uiicrystallized forms of hornblende, of which there are many minor yarieties, juet qb there are of mioa.

Augite in similar in aiirearance to hornblende, except that the crystals in cross section bIiow eight aides, as in pi. 13i fig, 16, and is much less important than hornblende to the student of roche composition, utttil he hns made some progress. We have thus two usually pale or wliite minerals, and three dark brown, greenish or black nniievnlR to deal with, and a very small amount of practice will enable anybody to pick them out easily. The knife will tell the difference between Quartz and feld&pari but mica, hornblende and augite are easily scratched with the knifCj, givine; a coloi-leea streaky and the dif- ference between the three minerals muat be determined by tbe shape of the crystals.

Many other minerals are associated with these, as fltanll grains of magnetic or titanic iron in granites, forming tte "black sand" of the miner ;but they are not CBsential constituents, except in a few cases. Garnete, tourmaline, olivine, chlorite, ehryeolite and apatite, the last four all green minerals, may occur in small er&iBS or crvBtalB, or may sometimes be so abundant

Pr08Pecttnb And Valxttng Mines.

as to giv€ B diatinct cbaraeter to tlie roik, vcfaiib may then be called! a "garnet rock," "chloiitic slate," eta., aa yiQ shall notice later on.

Kock Stecotcee.

All rocks present lines of fracture, even though they were deposited as a solid nass, but some present a aeriee of parillel plaoes Qloug which they iplit with great facility, sometimes aloug the lineti of original depoBit, and aoEQetimes nearly at right anglea to tho former. TbesefsBure lines are known AsHtratiflcatioix or lamination, cleaTage and bedding pIuDee, and it is highly important that they should not be confounded.

Stratificsdion is the result of earthy matter beicf; deposited in water aa layer after layer, with iuterTals of ixnx between the deposition of the layers, during which the tiret layer deposited had time to harden or form a sort of (ruat which prevented it mixing freely 'with the suooeeding layer and eo on; bo that the mass has become like a series of sheets of paper laid one upon the other, and when converted into rock by the lapse of time, amd. raised out of tbe water, the rocks split easily along these lines of deposit. The layers may Vary greatly in thickness depending on the amount of sedlnient brought down by the Btream and the length of the flood periodic. It ie eaey to underHtand that a stream during flood will carry immense qnautitiea of matter into a lake or the oceat], becoming clear during periods of drought, thus fulfilling the conditions called for and tht such streams as the Missiasiptii, Amazon and Ganges may form beds of vast estejit, while others may be limited to tbe area of a small lake. Bocks formed in thi manner are known as sedimentary or etratiGed rocks.

CTeauafe. '—Certain rooks, such as roofing slates, 'while belonging to tbe stratified series, have become so altered by pressure that they no longer split along the lines of stratification or deposit, sometimes known

liOCK-FORMIKQ MINSRAL8 AND ROCKS, 41

RB ''lamiDatioQ lineB" (a term applied to the tliiiiiier strata), but oa a series of joiuts which have been sub- sequently formed by tbia pressure, generally more or less ftt tight angles to the lines of theortjijiMal deposit. The old lines of Iniainatioii are obliterated and tbis new serieB of joints is more nmneroijs than the original homontal planes, find the splitting character much more perfect, dividing the rook into very thin sbpets. This structure isknowo as 'cleaTagie." It id more or less developed in coal beds and is there known as the "clenfc, " and is the cauae of the coal breaking into small piecea when mined. In crystals of minGralB the cleavage is the line on which the mineral splita most readily, and is usually parallel to one of the smooth faces (facets) of the crystals* Tbia is well illustrated in mica and gypsum.

Bedding Planes and tSirike Joints. — In addition to these splitting planes, all rocks (eren licoestone and eruptive rocks) have acquired two or three sets of joints, more or leas at right angles to each other, which divide the mass iuto large blocks and greatly facilitate the labor of tUQquarr.vman, who takes advan- tage of them in his mining aperationft. These may be altogether independent of BtratifiGation, being the result of the upheaval and oocapreesiou of the earth's crust, though in some cases they may follow some of the more or less horizontnl lines. Upon their char- acter frequently depends the shape of xaineral veiug and deposits. The joints which are roughly hori- zontal, or parallel to the original stratitioation, are called "bedding plauea" or "dip joints/' and the aeries running with ths general trend of the rocks through the country, the strike joints." These iointe miay be very numerous or wide apart, apd are the cleanest cut in close fina-graiued rocks such as limestoneaj where tbey are not obscured by the stratifi- cation planes, and also in Bome graniteH furnishing fragments of all sorts of angles. These joints may be

riiOBPnOTlN& AND VALUING MINES.

only a few yards loug or m&y extend for b mile, the latter feature being most prominont in close-grained rocka which Lave suffered coiaiiaratively little dia- turbancG. A little thought ttjU sbow "why buildinic Btones shauld he put into the atructure in tbe aant position that they had in the quarry, that is, laid ac- cording to their"beddiQg," beiug etronKei'in this way than any other and less liable to scale ofE, on exposure to frosts and the acids in the rain water of cities.

Me.iamorphum. — AU rocks are conatautly changing their character. The mud banks of to-day will be shalea and slates of tbe far future, and our sand banks, the saQdetones of a coming era. In the same tvayand by the same agencies of time, moisture, presauro and heat many of the older eedimentary rocks haTe lost much of their original characteT. The a&nd' stoncB have become mnasive quartaites, in which the small grains of quartz which compose the saod- stoDe are no longer visible; and the slates and ehales have lost many of their lines of stratification, bBsides suffering other changes which have Imparted to them n new common character, kn own as 'schistose/' Such rocks ore called Bchiste. It is Bometimea a very hard mattar in a hand Rpecimen of these rocks to determine by the eye whether it belongs to the metaraorphio or eruptive aeries eo eitetiaivG hsne been the changes, and only the microscope, or a dis- tant view, when the main features of the mass alone strike the eye, can settle the question. (When the raicroacope ia used in the determination of the rocks a flake of rock is ground down so fine that print can be read through it, and it is this l61m that under the microscope te] la the story of its origin and composi- tion). By reference to pi. 2, fig. 3j the difference be- tween tbe structure of slates and achiste will be better understood. The upper part of the figure represents n slate rock (let us say one in which there are numer- ous fragments of hornblende by way of illustration.

ROCK-FOBMINQ MmBRALB AND R00E8. 43

otherwise a hornblende alnto) and the lower part a schist having the sumo uonjpOHitiou, calied a horn- blende schist;. In the latter there h&e been Hucb are- arrangeiiieDt of the particles that though tbe dieiss retains some traces of stratiticiitio£i> in the paTallelisni of its bedding: planea, it has lost the smooth lamination planes and QODBists of a seriea of plates, tbickebt in the middle and thinning: out all round like a Hat lens, the result being a very characteristic appenrnnce (known aa *'foliated") in white only a few of the linea of etratilication have been preserved although the process has not been such as to produce clean-cut cleavHe. The result has in moet cases been to toughen the rook, felting tLe constituents together, and few are more difficult to handle than this same hornbiende schist, as it will not split and is much leas brittle than moat eruptive rocks. In these metamor- pbic groups the cbaugoa Lave usually been so great tbat all traces of foseils have been destroyed, and their geologic age can only he inferred from their associa- tions. They are abundant in volcanic regions and largely associated with mineral deposits. Their ulti- mate condition when metamorphiBm ia corar'lete, ap- pears to by a return to a rock in which all trace of its sedimentary origin has disappeared and which cannot be distinguiabed from those which we know to have had an eruptive origin. The term metamorpbism is not applied to the simple hardening of muds into slates, or similar proceBses, hut only to those changes in vphich a rearranjement of the particles has pro- duced a rock with a decidedly diSering appearance.

Classification Of Eockb.

Rocks may be divided into simple and compound, the first clftBS includiKE those which eousiat essentially of one mineral, such as some Hmestonea, gypsum, rock salt, and serpentine; the second including those which are made up of a combiDation of several dieaiuiilae iLiinerals.

u

PR08PEVTI2iG AND VALUING MINES.

The simple rocks resolve thcmselveB into two groups, the fii'&t of whioli consists of cheniical precipitates, and the second of organic Btructuree.

The com pound rocks resolve themselves into \fliat may be called the 'origicar group, coEsieting of those of eruptive or volcanic origin, wliich are again divided into the "plutonic" and "igneous" series, the former terra being applied to those rocke which have been intruded from below without reaching the sur- face, and the latter to those which have been ejected aa lava from volcanic Yenta; and the 'sBcondary" {jroup, which is made up of rocks derived from tb© wear and tear of all other rocts previously formed, whether original or already secondary- This group may be divided into the "stratified" rocks which have been deposited in layers by the action of v/ater, and those u'hich aie the result of volcanic outbursts other than lava, and which may be termed "fragmentary."

The stratified rocks are again devisible into the simple and metamorphic sections.

The boundary lines between all these groups are very poorly defined, and they can only be taken as gener- nlizations. Thus many limestoneB may contain so much sand and clay, alou 'ith their fragments of coral and sea shells, as to be almost a componndrock, but they largely lack the stratified character, while in the compound rocks many which have been ejected from volcanoes also occur in situations where they have obviously never been eiposed to the atmoephere at the time of their formation as the basalts in the coal beds. The following tabular presentation will show the general arrangement in a compaetform:

ROOXa CL&S3En ACeOlEDlNG TO OBIGI2I.

BnnxK Rocks.

t, Cheviica Deposits—eaaHi as some limestoiies, rock-aalt, fTisum,

n, Organtc ZJepesift— Bucb as wme llmeetooea, ctuUlc, infusoria] -earth, coBit, etc.

ROCK-mRMlNQ MINERALS AND HOCKS. 45

. CoMPofSD Rock*. L Ortgifidl :

1. PlucoDic series— such as gratUte &riiito, etc. 3. Igoen'Ua serlos— Buch bb basalt, trachyte, to. II. SeatTKdoTV Qfoup:

1. EtratiOed Rocliai

a. Simple— such oa shbEes. samlstiDea and caojc'tQtiieratiM.

b. MeuuuorpbJc— auoh aa quanzitB, goapetrine, shteta, sta. S. Fromtiiitary Kooks— audi ai> breccias, valcooie Lufiui, and

fllaelol deposits.

Simple Books. — Ag the limeatones foil within the limitB of bath the divisions of thiB class TkO attt<mpt ViiW bd made to treat the Bfiatioos separntely. Rook salt aw coal fire very important commercially but the lime rooks from tlie great bulk of this series, either as sulphates (gypsum) or, more commonly, as cgrbonatea (Umestone, oaloifce). The great mass of limestone has bean segrogtecl from sea water, into which it has be6D carried by the atreflma which haye disaolved it from the rooks throufb whioh their waters have per- colated.

Limestones proper vary in hardDBsa from very eoft to quite hard roakj, compact and usually close-grained in structure, rauging: m color from white through Bhadea of yellow aud drab, to blue and even bUck, And conaiet eaaentiaily of carboaate of lime, which effer- vesces on the appUoatioQ of acida; aud they may oon- taixi so many impurities, such as clay, saad, etc., that they btecome uuauitnble for the mao-ufacture of quick- lime for buildiQ; purposes. This arises from the varying conditions under which they have been. formed, and which determine their character. A targe portion of theia oonaist of the rocky skeletouB of oorala or the sheila of minute animalcules.

chalk oouaista of the minute shells of a vast group of small animals called Foraminifera, which live in sea water in countless milliona These extract the carbonate of lime, which forms their shells, from the sea water, and when dead they fall to the bottom. forming a soft ooae, which if exposed to view in future ages would be the same as chalk as we know it. These

t

PEOBPBGTlSa Am) VALUflTQ MINES.'

aliells are so minute tbafc only a powerf al microacops oau abow theii' forms, aad it takes miltiotis of tbem to form a cubic inob of rook, Tli6 purer forms of chalk are soft, -white and earthy but Urna haa wrought such obaagfla that Bome of Us Turietiea hecome more and more oomiJiiot, until tbay grada into limestouea, and the orgauLo £oru][itiouii huv9 had thtiir coustitiieats so modified that uearly all traoe of their organic origin has disappairad, aud tbay can scarcely be distin- guished from the granular uryatalline chemical deposits.

FJ,iRt, wliioh is a form of silioa, occurs in the chalk beds, aud hag iirobably been formed by the aeparatiou of amail quauititied of silica from uome of the orgauto remains, by pBruolating waters, and ita concentration into rough nodules of very compact structure, usually dark or blackish in color, aud resembliu horu or ifUsB in tbin fra;?mcuta.

Cm'allinc Li tn*'M<inf>.:i. — Imiuouse dejiosita of lime- Bton have been built up by coivil inaeuta, like tbe reofs ao common in the warmer seas of tbe wurld at present and ttiese uaually coutaiu uumeroud fosilu which tand out more or lesB promiueutly on tbe surfacea of the rook ivhicb have been weathorej by the action of air and water, though thay may be indistiiiguiBhable on a freshly broken surface. This probably ariaeH fom the greater solubility of tne uuGryatalUaed portions of the rock.

Other deposits have been made up of broken frag- ments of coral detached from the main reef, and washed upon the adjacent beach, where they have been mixed with Baud and broken ea shells, forming beda with many impurities.

Besides these, there are compact beds which appear to have been chemicftlly deposited. To this section also belong those deposits made by hot springa which deposit tbe excess of lime held in solution on cooling as '"HiLter,** a term applied to all euch formations.

nOGK-FOEMmG MmERALS AND ROCKS. a-?

whether formyd of Hme or silica. If made of the former, they are known as 'calcareoua siEter/' if of the lattQi' as "siliciouB giutdr."

LimestoDes for making quicklime Bbould be free from silica. "VVbeii this is present in cocaiderable quatitititis, it cot infrequently makeB Itsulf vitjible on the weathered aurfaoea, imparting: to them a peculiar dry bai'sb feel, the Ume wearing away more rapidly tbau the bilicioua portion, which is thus left m re-lif on the expoaed surfaces. These siliciocg limeatones and those carrying clay or alumina, which are not suitable for the production of ordinary lime, are util- ized in the manufacture of hydraulic cementB.

Marble is a variety of limeetone in which the entire mase has bsoome highly crystalline. The finest varie- ties are aa clear and een in grain as Inmp sugar. In colors there is an itifinite variety, many kinds being often found in the same belt. Freedom from iron min- erals (which will ruet and stain tbe dressed slabs), purity of color aud cloaeneas of gralD are the chief filfjinents in determining tbevalue of marble, but cheap, transportation to market is esaeutial to the successful opening; of a Quarry, however good the stone may he.

Duiomife is a maneaian limestone, conBiating of the carbonates of lime and magnesiaj usually' of a oryetal- inete:xtnre and j'elluwisb tints; and while some bodies appear to be original chemical precipitates, others are undo nbte dly orcl inary limestones which have been changed by the percolation of magneBian waters. Both tbe ordinary carbonate ot lime and the magne- isioB variety are used as duxes in tbe smelting of iron lead, but all limegtcnes are not of equal TaJue for tiiis purpose, any more than they are for qnicklimie. A chemical aualysia or practical test must determine their value for both purposes.

llagTifsite in compoeed of carbonate of rnflgnesia, and is much Ubh cominon than limestone or dolomite.

Limestone crystals (calcite, calcsiai*) are often jnia"

PMOBPSCTmO AND VA}

MIIfES.

taken for qunrtz, and as it is a frequent accomptmi- laont of metdlio ores, the chief diSerences are worth noting. In cryetallized limeBtone the characteristic shape IB ibomboida!; that ia, the crystals are four- aided, but Eone of the angles ai'e right angles, while each pair of sides ia parallel. When crystallized in pointed forma uith six eideSj the crystnls are like pyranjxda, without the Btiaight portion seen in quartz, and tbe apex is more pointed. This eharp-pointed character has given it the name of dogtooth spar." In addition to these difffcreuees it is much softer than quartu, being easily scratched by the hnife and splits easily along the line of cleavage. Carbonate of lime (caloite) is not liieJy to be mistaken for any other mineral than quartz escfipt feldspar and gypsum, and from these it mey he distiuguished by the action of acids, or by the £re test to ascertain if it 'will form quicklime. This will set slowly, whereas burnt gypsum forms plaster of paris and sets promptly when niised with water, hut does not become as hard as the cements made by calcining silicioua limestones,

Gypsum (suiphate of liiue) differs from the carbo- nate ijj that it does not effervesce with acids. It is valuable chieHy as the source of plaster of paris and aa a manui'e, the latter consinting simply of the raw puU verized rock. Gypsum cristalJizea in white translu- cent masses wliick scratch Teiy easily and split into thin uou'elastic llalies, which may sometimes bo ob- tained of great size ; this form is hnown as

Seliaite. — Fibrous, very Bilky varieties of gypsum are tnown as "satin ;" and the close-grained forms, when of even texture atd £nely crystalline are distinguished as *'aiabaetar "

Infusorial earth resembles chalk in appearance and general constitution being made up of the skeletons or shells of minute organisms, but the term ia ggtiei- ally applied to those which GouHist of the scales oi little vegetable organisms called "diatoma/* These

BOCK-FOnMinG MI'NERALS AUTD ROCKS. 49

are maJe of Biiioa inBtead of lime, asd consecLuently tbe rock is not acted on by acids. The excessive fine' neaa of the powder derived from crushing these earths, flud the bardneBB of the individuol particles, make them veiy uettful for polisbing powderB which are known conHnercially as "tripoli," "electro Biliaoa," eto.

Serpenh'ne ia essentially s, hydrated silicate of mag- nesia, and Ib a dark blackish -green rock, with very Bmooth eli]i|-iery joints, gen&rtUly hithly poliflhed and variegated with greenish or yellowish tiluis, like soap- stone ov Fi'ench chalk such as is used by tailors. The luore brilliantly colored varieties are used for orna- cieutal stonework, under the Prench name of *'verde antique."' While some eerpentine§ have been original deposits on the sea floors others have been in all prob- ability intruded masses of eniptive rook, containing olivine, t?hiab have undergone extenBive metamor- phiem and assumed their present aspect.

Compound Rocks, OajQiNAL Group.— Instead of de- scribing these rocks under the two scrioB named in tbo table, which is based on their origin, and often calls for extended inveatijafcion to determine to wbioh series any particular rock ehould be referred, it will be suiOSciettt to beire classify them by some striking physical peculiarity Tfhich ia easily recogniaable by every body.

Three distinct forms may be recognized : (1) Those I which are entirely crystalline, or made up of a mass of crystals each of which is digbiuctf (2) those in which a certain portion of the crystak are scattered through a "paste" of feldspar, which is very compaofc and does Qot show any distinct structure; and (3) those which do not show any signs of crystallisation, but are of the same character throughout.

lb must be understood that this arrangement is purely arbitrary, as it separates closely allied forms; but it possesses the great advantage of being apiili-

PliOSPEGTlNG AND VALUINS MINES.

oflble Without the use of the microecore, whicli is seutiiU to auy scientific classificEitioi]. In thia place the object ia simriiy to enable the Juiner to find out the approsirnate name of any piiirticnlar rock with the amallefit amoiiut of trouble, and not to eduonte him for an expert petrologist. Only the moafc oharncteriB- tic of tliGfle rocka will be described.

lu the crystalline rocka the size of the crystals does not change the name of the rock. The stse of thd cryetals may be said to merely indicate the rate at wbtoh the mass of rock cooled aod the amount of prea- aure under which the cooling took place. If &n ejected lava cools very rapidly there is no time for the ratticies to arrange themselves in any particular naan- ner and the produat is a rock which has all the ap- pearance of the filag from a ameUing furnace. If the rate of oooliug has been slower we have a crystalline rook in wbicb the separate oryatala are amali and if the cooling has been esuesbively slow we may have large and well-defined oryatals, there having been ample tinie for a oomplBte arrangement of all the con- tents of the rock into their respective kinds, ftceording to the proportions of the varioua coustitnents and their relative affiuitiea. "While thia may be stated as a general proposition it must not be taken as an abso- lute rule, as it may be varied by the more or less easy fusibility of the diflEerenfc minerala varying the proo- esfl. These rocka vary greatly in their mode of forma- tion, though they all ag:rGe in their comparatively deep-seated origin. As they are intimately connected with the great changes in the earth's crust, and prob- ably owe their fusion to the heat developed by the immense pressure aud friction incident to tbeao changea (and perhaps b' chemical action), it is not surprising that we find them cbieBy in those localities where these changes are mogt actively at work, namely in the great mountain ranges. They may be found as great bosses or as dikes which have been squeezed into

'Rock-Forminq Minehals And Rocks. 61

the rocte from below while in a plastic or semi-fluid condition, ay in tile case of some grnnites (pi. 5, fif!. 6) or of the trachyteB sbown in pi. 5, ligs. 1, 2 aud i. Id the Intter case tbe force exerted was not suEGcient to break throuy:h the crust of overlying roct, hut wfia sufficient to lift a jjortion of the surface into tbe foru] of a dome, the Hence formed being filled witb the iDolten rock, a roi'tiou of which through amnller vents found its wi*y JEi the horizontal layers of the fiedi- mentary rock, forming boda between them, just as the basftlt lava hos found its wny into coal seams, as shown in jil. 5, fig. and between the shales as in pi. 5, fig, 3. In theeo fi-iures No. 4 shows tbe theoretical structure of Bucb a lava roass, ehowinr the pipe a through which the Java (black) was seeking an outlet and the lava forming a solid mass with branches peQ£- trating the overlyiiic Btratn, and forming thin beds between them. In Ar. 1 we have the top of such a msBS exposed in tbe side of a cailon, of which a 6 is tbe bed, with the strata (pnitiHlly worn awjiy) ourvinj; over the solid lava; while in fig, 2 we have an actual cross section through a mouotaiu forjued out of such a block, the solid lines showiuy; what remains iu ivlace, and the clotted lines the orl-nnal shape of the portion which has been removed, a being the bed on which the laTa (black) spreads out, and b the shales, between the Iftj'ere of which thin aheeta of lava found a lodg- iDent, as shown by the alternating outcrop of c, c In fig. 3 we have similai" horizontal beds of lavs Cj pene- trating the strata as offshoots from the dike dj but the lava ate is evidently only the remains of a similar sheet from which tbe superinoumhent Btrata have been worn away, and not an outflow in the open air, bscauae remains of other lava sheets are found obove other strata at higher levels, as at e. In fig. 6, a, are shales, b coal, and c basalt, the latter intruded into the coal bed through the dikes d, rf. In this case the ctial is destroyed and the lava, originally black, has

PROSi'ECTINQ ANB YALUTNO MmSS,

been altered to & whitish look by the aotion of tbo coal on the cooliog lava.

In othtir oftses tlio lava hs forced its way to the eur- taae, through the tifisuredi rockB, and overflowed from the ilike in immense sheets, or has beeL ejected from Yoleauio cones iu huge streaniB which have traveled many euIIjb, filliD up vullejs and even continuing their coume under the aea. Similar eruptioQB take place on the sea floor. YoJcauic emptions are alao fre- quently accampanied by the formation of vastfla&urea on the flanks of the uiouiitaiu which becoroe filled with, lava, and iiU tbeee exhibitions of deep-eeated lieat pro- duce profound changes in tbe rochs which tbey traverse, tbe heat of lava streams being preserved for many yeara after all volcanic activity has oeased, so alowly do they cool when once crusted over.

It iH thus evident that the same body of lava may cool under very different conditions, and these have more or less effect on the appearance of the rock, so that tbe determination of the dierent kiiids is often & matter of difficulty even to experts.

ORiaiHAL Compound Euoksj First Gkotjp (wholly crystalline).— Adopting: tbe simplest though arbitrary clasaiflcation for tbe suke of convenience, and disre- garding for tbe present purpose dillcreueea of origin, the compound "originar' rocke (iuchiding both plu- tonio and eruptive rooks) of tbe first group embrace such species as granite, syenite, felsite, elvanite, iraehyte, basalt, etc.

Grauite ia a mistjre of iiuaifca, feldspar and mica. It may be either fine-y;rained or coarse, and vai-y iu color according 60 tbe color of some one of its constit- uents. If the inica is white, we have a neai'ly white or light-coloi'ed granite; pink and red granites tak their oolor and names from the tint of the feldspar, just as very dark or even black granite results fronj the abundance of black mica. When the feldspar ib white and mica black in moderate (luautities we have

Roceforminq Minsuals Ab Hocks. 53

rarious tintR of grny- It is often traveraed hy dites of younger age, usually paler in color and more com- pact than bbe rock which they cut; and though caJled the oldest rock, it is fregoently found as Teios (con- nected with the main mass) which penetrate both the stratified and uustratifiod rooks above it (as shown in pi, 6, fig, 5), which are uaually much altered thereby. Granite belongs to the group of rooks called "plu- tonio, " wbioh have not broken through the surface of the earth's oruat, but have consolidated at some depth beneath it. Sometimes hornblende is present in small quantities along with the mica, when it maybe termed botnblendic eranite, on the prinoipJe of nemg aa a descriptive adjective the iiAme of any peculiar mineral present in a rock but not esaentiai to its coDipoBition,

Granite geems to be the underlying rock of the entire serieB, and if thin be the case it is not strange that all the rocks which have been derived from it ehoTild show a tendancy to return to it, in appearance composition, during the lapse of time, through the ageneiee of heat and pressure,

Felsite fehiie-porphifry and elvanite are orystalline mixtures of quartz and feldspar, usually bo intimately mixed that in felsite the crystallization is scarcely vis- ible, while elvanite is more diatinctly granular. The latter rock is of frequent occurrence in the mining dia- triota of Cornwall, and the dikes of it are known by the miners aselvniifi/' from which term the saientiflo name of the rock has been derived.

Trachyte and EhyolitG. — In many respects trachyte resembles granite but may he easily separated by the feel of a freeb fracture, which iseiceedingly sharp and rough, sugrgestinff the surface of a cat's tongue. It oceyrs a& dikes and large eruptive overflows, belong- ing to the aeries of modern lavae. In color the rock has a wide range of variation from gray to pink and brown. In composition the feldspar predominates over the quartz and is usually accompanied by horn-

PKOSPBOflNG AND VAL UING MINES.

blende, mica or audita- It may be considered the niodtii'ij eqnivalsnti of tbe older granite, but differing from the latter in being a volcanic product. Ebyolifce is auotber rock bo cloeely related to trachyte that the beginner will £nd it burd to separate tbeui. As the mode of otcurrence and general associationa are entirely similnr to tracbyles, the distiuutiou is not at eeaential consequence.

Syenite. — The foregoing rocka have quartz aa an esaeDtial constituent, while in syenite and basalt it ia absent as free or visible quartz, or nearly so. For- merly syenite waa considered a crystalline mizture of quartz, feldspar and hornblende, but the term is now used for a rock tnarie up of crystalline feldspar and hornblende, with mica ils an accesury or accidental mineral. In appearance it strongly resembles granite (but the knife i.vill abow the absence of quai-tz), and oocura in much the same way. The feldspar haa a different compositiou from that found in granite.

Bamlt is the last of the wholly crystalline seriea which need be noticed here. It is usually a very daxk, blackish, Bne-grained rock, ooneistin; of feldspar and augite, with a variety of associated mincralSj such as olivine, occurring as small olive-green gi'aiBS, of which the oxides of iron and manganese form about 15% of the mass, making the rock unusually heavy (ap. gr*, 2.95). It has been ejected from modena volcanoes in immense quantities, covering hundreds of square milea in the States of Washington and Oregon, the suc- ceasive eruptions or overflows from dikes forming a series of layers, resembling atriitu, and having in the fljgregate an immense thickness. It is also the rock now being ejected by the volcanoea in the Hawaiian Islands, and, from ita fluid character when molten, forms perfect rivers. It was such iava streams whicli filled the mountain-valleys of California and oovared the Eold-beaiing gravels during the second outbreak, as the tracliytea bad previously done at a mucli earlier

ROCS-FURmNQ MINERALS AD liOCKS.

period. When cooled rapidly as on the auifaoe of a new outbreak, it becomes full of bubbles formed by the expansion of the steam eoutaiued in the lava (to 'which it owes its di]idity} and it is in theee critiea thfit ojials, calcite nnd similar minerals have been foriaed bypeiuolatiug watere. The porous lavas, with the bubbles so fiUeti. are known aa amygdaloids (from a wordmenDiug almond). Below the surface the preB" sure haa prevented the expansion of the steBm so per- fectly, so that the bubbles got smaller and smaller till the maaa becomes perfectly firystalline. Very fluid lavas may be no filled with theee air, gas, or steam cfivities that they look spongy And will float on water as "pumice stone,** or they may be drawn out by the violent winds eddying round the crater into fine threads like spun glass, in wbioL form they are known as "Pele'a hair." Pele being a goddess associated with tha HawaiiAu Tolcauoes. Basalt frequently crystallizea into a columnar structuire, thepillttre being fire or six- sided, -ith ball-aud-tfocket Joiuts. This oolnmnar structure is always at right angles to the sheet of la-va, BO that in dikes they forim more or less horizontally from 'Wall to wall, and in overdows more perpendicularly.

Second Geoup (porphyritio). — In this group we bave quartz-porphyry and a whole series of other por- phyries in which visibte cfuart is absent and which for the purtJOBes of the miner we may designate siraply as "porphyry/' using the term as a general one.

Quartz-poTphyry or dadte conaistB of a paste of feldspar whieb shows no Bign of crystalline structure, the color of whioh may range from dirty ivhitetopink, purple, hrowu or slate-gra}'. In this paste are scat- tered -email grains of tratieparenb quart:;, making a very obaracteristio rock whioh occurs in large masses, the rock belonging to the series of old lavas. It is largely developed in the Gomstook mining region.

Porphyry, — Under this head may be clasfied all the rocks iu which the pasta just deaci-ibed uontaina difi-

Prospecting A 29 D Yaluinq Mines.

tiQct oryFtBlaof feld8pnr,giviQe tbem n spotted appear' anoe. They loay contain iiiica liorublettde or aujjite aa an additional mineral, and it ia the presence of tbes6,Hloiig 'n'itb differences in tb€ coiapOBitioD of the feldapsrs whioh conatituteathe basie for a new name.

They occur aa dikes, veins, intruded sheets, or as Burfaoe (lepoaits, and iuolud sucb species es porpby- rite, diorite or greenstone, andeeita, phonolita or clinkBtone, etc.

Thied Ghottp (non-cryBtfllliD6).In this group we h&Te pumice stone, alrendy described, and aB the prin- cipal rock —

Obsidian, "which is a lava cooled Tery rapidly, look- ing like coarse bottle glass, and hence frequently called "volcanio glass." It is of various shades in greenish black, blaok or red, and the red varieties are Bometimea marbled with black streaks which are drawn ottt in the direction of the How of the lava stream while yet hi a pa&ty condition.

It is not pretended that the foregoing descriptions are absolutely scientific. To lead the miner into the myBteries of orthoclase, plagioclaee and triclinic feld- spar would be to hopeleesly bewilder him; yet many of the distinctions between the various eruptive and intrusive roeka are baaed on the one or other of these feldspars being tbe predominant cotnponent. The use of a powerful microscope ie often necessary to settle disputed QuestiouB, and all rock-atudents know bow many of these there are. If the descriptions will enable a person to distinguish a granite from a por- phyry, a felaite from a basalt, or a trachyte from a quartz-porphyry, they will serve their purpose; in- deed, they would! almost do so if they will separate an eruptive or voicanic rock from a ecbiat, and a schist from a shale- The student who once begins to take an interest in rocks will soon discover that their varieties are almost infinitct but that they resolve themselveg into a few tolerably well defined groups, and will in-

nocE-FoRMmG umEnALS and hocus.

evitably he led to examine into tlieir diflerencea and perpetually to aek himself the reason wliy. When tha eye i& tbtia trained it is tiiU6 enough to name tlieas sliUtOT difiereuces, which are pusaliag enough to expert observera.

A general term for many of these eruptive rocks ia "trap," from a Suandiuaviau Tvord meaning steps or stairs, in allusioQ to the forms in which they often "weather." This wwatberingj a term applied also to the changes which take place on the surface of rocks espoHed to the deatniotive action of the elements, is Bometimea of great assistance in doterminini the true character of the rock especially in those with a fine grain and dark color;, as the feldspar on exposure, instead of retaining the glassy look which it may hve in the ruaaa (making it hard to reoognize), becomes milky white and shows distinctly on the surface of the bowlders, even though in a clean new fracture the latttr ma.y bs neatly uniform dark bluiah-gray or almost blaok. Ia other cases the outer surface may be pitted with little angular holes from which the crystals have been dissolved, thus readily separating the rock from the stt-atified serieR to which it may otherwise liave much resemblance. If depending on the pitted surface, however, care must he taken to ascertain that the pita are not "caats" of crystals of iron pyrite, as this mineral is abundant in all rooks whether eruptive or stratified, especially so in the former wheii decompo- sition of the luioft or horubkude has set in,

Seoosdaky Compound Eocss, Stbatifieu Sehies. — -The character of the rocks which are in process of dooay aud are being swept into the smaller streams and theuee through the rivers to the ocean, plays an im- portant part in the formation of soils and the Bedi' roenta cairied away by water and deposited to form rooks. If granite were the only rock being worn away hy a stream, aud the diaintegration were complete, we fthould have clean deposits of Band aud clay full of

riiOSPECTlKQ AND YALUmCf MINES.

coiofi and lioinljleud*?. Bvit Tvlien the stream began to cut irito other roeks terti would ensuG a oljoiige in the cliaracter of ths depoeitSj which would become yet more Htrou<fIy lUQiked if the deetructiou of the rooks had extended iuto groups already stratified. It ia, therefore, eas.r to pee that the conditious surrouud- ing the forinatlju of stratilied rocks are very complei, and W6 iiiut loolc for great fooal diifersnces even in rocks madd at the snrae greologic period. So great ia this diflereuue ftt times that it would ba impoBaible to place juauy locka in their right chronological order if it were not for the fossil remaitiS with which they abound, so thfit the prospector should religiouely pre- serve all such fosisils as he may find, or take such a note of the locality that he may direct others to it.

The ultimate flnalyatjj of the foregoing compound original rocks gives approsimately the percentages ahoffn in the following table, compiled from Geikie, from which it will be seen that they resolve them- selvea into three groups chemically. The large per- ceotage of iron and manganeae in the porphyries and basalt ia largely due to the presoDoe of grains of mag- netic iron in the porphyries, and the oxides of iron and manganese in the basalt-

CHEBnCAL COMPOSITION OF OEiaraAL COMPOUND BOCKS.

Ouaitnlte

Sj'esjtCi,

TrachyMJ

Ptn?pliyrieH... BOElJt

gUlca.

Alumiim.

Lime.

Iron, Man- ganeae, etc.

14. Q Ico

Fotaali.

Boda.

S,S

Mogned*

The potash, soda and magnesia, being soluble, aro carried away on decomposition,, and foi'm the alkalina matter which aooumulate in lakes without outlets.

MOOK-mBMINO MIN&*BAL8 A2fD R00K8, 59

such fts \Vslker, Mono, Pyrnioul, and other lakes in the Great. Bqbiu between tba Sierra Nevada and Bockj Moulitaiu raugeg in tlie Uuiteil States, giving tbem their inteuBely ealine cb&rfioter if ibe rocke fuiniBbiiig the material, contain but little magnesia, tind a hitter taste if there be much of the latter present. Thus the draiuAgo of a basalt regitiu should furuigh maguesiaD and'of a trachyte couuti*y saline waters.

The silica, alumiua, liiiie and iron are thus left to form the aedinientary rocks. The iron plays its part chiefly as a uojipouut of the clays and a cementing tuaterial for the flaudstones, to be aftenvaid leaebed out and accuinnlated in local deposits as bog iron, which by the chany;eB of time becomes the source of other iron dpotjite of vatioue kinds. The lime, being leBB Boluble than the alkalies, in Blo'cv-ly leaclied out of some of the rocks, especially by water containing car- boDic aciil, and redepoeited on exposure to the air as tt Bediuient by the springB which hae dissolved it, or is carried to the ocean to furuisb material for the coralline structures or the shells of its multitudinous life.

The quartz and clay, the chief constituents left, fur- nish the bulk of the aedimentary materidl, which, with the addition of wateriTorn fragments of undecomposed rock imturally rttsoWes the depoeita into two series, to tbe first of which belong the conglomerates, gravels and sands nd to the second the muds and clays (derived chieHy from tfae alumina), shales and slates.

All material wasbed into a stream by tbe rainfall on the adjacent hills, and falling therein by the under- mining action of the current on tfae banks, becomes a source of sedimentary deposits. If the frai;:!inent8 are too large to be moved by the current, they remain in the fiti'eam bed until gradually worn away by the attri- tion of smaller rocks and sand over them; if smaller and movable, tbey are onb' carried along to the first dead water, whether it be a lake or the ocean, and thera

€0

PBOSFEOTlJfG AND VAL UIMQ MIMBS,

deiiosited, and this cleposition inTolvea a sorting of tbe inaterifil. The larger and heaTier pieces will be depoaited firet as coar&e gravel, theu finer giiftvel, then atid and tbe linest Bediiueiit Leing carried the fur- thest will be lait doivn as mud or silt, unless the lake be ao small and the current of the etreani so awift that it is Swept into tbe outlet beyond, leaving only a deposit of sand and gravel. It will thus be seen that the eame material may appear as gravel atone place sand at another, and mnd at another. But Jarge etreanjs npiially carry only the finer sediments when they reach coKiparatively level country, having left the larger particlea at tbe foot of the mountain slopes, and as in the case of the Amazon they may spread this over a sea bottom hundreds of square miles in extent. A similar procesa ig carried oji at tbe sea beaches where the refills of the tide may carry the finer material sea- ward, leaving the coarser at tbe foot of the blufEs.

"While Bti'atiflcation usually occurs horizontally, it is not necesaarily so, as in tho case of mountain streams the coarse gravel would accumulate the moat rapidly, formiug a sloping bant, on which the layers deposited in successiTe flood times woidd take the fiame iiiclinntion. So, in like manner, the ashes ejected from volcanic cones, falling on the sloping sides of the same, woukl accunulate in layer after layer, preRenting all tlie appearance of deposits made in water, but retaining the slopes of the flanks of the cone.

Conglomerates are largely formed on sea beaches by tbe rolling of the rocks washed out of the shore bluffs into rounded fragment?, whjob will naturally be of various kiuda of rock, according to the material of tbe hills wbicl] ale being worn away. Deposits formed by rirer action are apt, from the circumatanoea under which they are formed, to be miicb more limited in extent than those made along ahore lines. They con- sist of rounded pieooa o£ rock of various kinda

ROCK-FORMlJS{ MtHSHALS AND ROCKS.

oemeiited together either with hardened cUy or silica, and Bometimes with iron oaides deriveil from percolat- ing waters or the black sand. They may be fairly fine if made of jravel or excessively coat'e, Andj if made up chiefly of oue rouk, xay be known by the toaiae of that if it ia specially desired to distinguish and sepaiute them as quartz-cougiomcrate, or trasbyte-uoDglomerate Buuh as iu iouud in (lonnectioD with the lavae of the California gold-gravel chauneJa. tome of the sehigis contain bowlders, leading to tba coDclnaiou that they are, in thia caee, merely altered or metatiitorpLio oonlomerstes; and in otbr cases the ceineotin process is so perfect and tlie consolidation of the mass bo complete that the pEibbltJB wiU break in two on a general line of fracture, without becoming removed from the inaKS. Guttinga thi'ougb conglom- erate beds stand, %¥ith nearly vertical walls.

Sandstones consist easentially of sand cemented to- gether ivith irou, each grain being ooated ith a thin film of iron oxide> which imparts the general color to the maBB, as in the red Bandstoues. The grains of sand wbeu cleaned of the coating maybe either tinted or colorless. Mica forms a ootamun additiun to many flajidstones, aa well as Hme and clay iven they may be distinguiehed ns mica-sandstone etc. The lime and olay are not readily discernible to the unaided eye. Flagstones are oniy aandatoues which split easily Into thin slabs, suitable for sidewalks, luhrstones ora Baudetones so thoroughly cemented that they are very hard aad rough enough to furnish the grinding Burface required in millatones. "Freestone" ia aome- timea a sandutone vbich cuts freely in any direction,, eitbei' with the etratilication or across it, but hardeua on exposure to tbe air. The term is howeTcr soine- times applied to limestones and other rooks which present the same c b ar a c tori sties.

QuartzUe ia a sandatone which haa been subjected to tbe action of heated waters which have aggregated

Prospegting And Valuing Mines.

the grains of sand together itb a Hilicioue cement, probnbly derived from a partial solution of tbo grains of eantl tLeiBBelves, until the rock has loat its granular structure, nd to a large extent resemblea maigsive quartz. It ia a comaioii rocli. 'fa tnining regiotis and occurs with other metamorpbio roots, but also in situ atiouB where the associated strata hare undergone uo

Clayfi are formed out of the alumina in the feldspar and other minerals silica excepted of the eruptive or volcanic rockB, and are the iQnesfc of the sediment car- ried in suspeijjjiozi hy water, varying in color and com- position according to the rock to which they owe their origiDj, and the particular stage in the journey of the stream at which tliey were depoaitotl. They may he exceedingly pure in which case they are called 'fat" in the language of the brickmaker and potter and from this range downward to a clay loam, in which there may be a very larg esoea& of impurities, of which iron forms a large pai't. The richer cJaya renuiro the addition of sand to make good hrick, but poaaeBB the advantace of a more uniform composition, which enables tbe manufacturer to regulate the addi- tion of sand to a nicety and thus produce an article of uniform quality; the poorer kinda make only the most inferior gi'adea.

Fireclat/. — A good fireclay has a composition of aliioa 73,82%, alumina IS.SS, oxide of iron 2,95%, water 6.45, with traces only of lime, sulphur, mag nesia, soda and potash, which is very nearly the chemical corapoaition of granite, with the lime, potash, soda, and magnesia eliminated, so that aucb claj-s could easily be formed by the decomposition of that rock. Fireclay is largely associated with coal aeama, the clay floor retaining the waters which made the tangled swamps in which many coal beds were prob- ably formed.

Kaolin or porcelain clay is derived from the decom-

ROCK-F<mMING MINERALS AND EOCKS.

pUBitioa of the IsldsparB of tbe granitic rocliB and por- pb.vries, and is tniacntial].' a aumpoiiiiid of oxides of silicon and ttlumiunm mixed witb water, tba oompoBi- tJon wLen pure being silica tifi.li,, aluniiiia 3t>.8%, vrater 13.9%. Iitipuritics are froqiieutly prflseiit, the principal one being iron derivod from tJie other mlQ- erals present in the rocJt ftoin which it waa foi'med. When pure it whiie, raujiDg through yellowish to brownish red, wheu irnich iron is preseut say h% or upward. The preparation of the clay by grinding washing and settling ig n slow And tedious iirooesa.

Shales nre only hardened clays which have been de- poBited from time to time in thiu eheetsj so that the resultiug naaes splitB readily into thiu layers along the lines of deposit; but while they uU retain thie common character, they vary greatly in composition, and may be distinguished from each other by the nRmes of the minerala which may give a speciul appearance to the rocks aB mica-shale, horublende-sbale, siliciouB ahale (wheQ aandy) or simply ciay-shale. In color they vary as much as in coxui>oitiaD, from pale gray to blaok; in the latter case they are usually colored by small scales of graphite— black-lead or plumbago- — derived from the carbon of the organic matter washed down with the clay sediment and buried with it. This organic matter may be so ubundaut that the Bbales may b6 called bituminoua or oil-shales.

Siatea. — For all this series of rocks the term elate IB aleo very generally used, ss clay&late, mica-slate, etc. ; but, strictly speaking, the term slate is applied only to those rocks which have lost their shaly char- acter by end pressure on the strata, aud now split on the lines of cleavage as rreviouslj" defined such as roof- ing slate (pL 1, fig. 4). tn these latter rocks the particles have reairaneed themselves at right angles to the line of preeure. This effect baa been repeatedly produced exprimeutally and the Btudcnt must early relinqnish the common idea of the absolute rigidity of

64 Prospecting And Valuing Mines.

Tockfi. Aa a mstter of fact, tLey.are plastic or m&.v be molded to an extraordinary degree, nianj of the shales and slates buviug beeu folded and wrinkled like sheets of paper aud this uot only ou & grand scale, but dowu to tbe most miuiite plications. Samijlee of this fold- ing are shown in pi. 12, fig. 8, iivhere the folding eltimeut has been the iutrusion of the dike rf; and in pi. 4, li. Gj where the cause has been general lateral preasure, crowding; the rocks into a amiiUer amount of apace horizontally, Kot only can cold kad under a sufB- cient pressure be sciueezcd as a jet throng:h an aperture suitably provided, but cold IroL also be pressed so aR to penetrate into the augles of suitable molds. This facility with which rocks can be modified in their structure, and bent and folded, has nu iniportartt in- UuencG on tJie filling of veins, as intense heat is developed in the pro(.:eBs, and this, in the presence of water, will decompose and rearrange all the eompo- neDts of the rock, disyolvlrig some which are replaced by new combinatione and producing metamorphiem.

Segokdaet Group, Metamorphio Series.- — All the shales and elates may be thus converted into schists previously described- As in the case of the shaleSj each variety may be distinguished by the predominat- ing or cbatactBrifitiu ttiiiiertil, as mica-sckialt which gradually shades off into gneiaSi which ie a rock hav- ing a composition exactly like granite hut without the uniform orystalline cbaraoter of the latter, or the foliated Btru<::ture of the achiste. In gneiss there is a tendency for all the mica to be laid in horizontal or more strictly speaking parallel lines, while the quartz may occur in pure baudsj and there in & teodeney of the mass when viewed on the large scale to look like a coarsely stratified rock. Prom this chai'acteriitic ap- pearance there may be a gradual change until it is hard to aay whether the rock should be called gneisai or granite, leading us to the conclusion that many so- (tailed granites are only the laat Htage.of the metamor*

ROCK-FOnMlNG MINSRALB AND ROOKS, 65

pliisni of au original sandy "bed of olay oontainlLg mica, such &9 are oommtui eyerywbere.

When hornblende is the chief mineral, we hare hornhletide-&chist a tough, dark greenish rotsk, which shales o£E itito a rook so essentiaily compoged of horn- blende that it loses the schttoide characiter od be- comes what is called hornblcrtde rock. When the sbadiog ciff ia in the dire<:tion uf a more ufyBtallme structure, tho gradations may be toward a hornbtende- gneisSf and from that to syeuite, juat ae the mica sohiBts grade into grauites. It will of course, be understood that theae changes are not to he seen small sfieci- meuB, but only in tbe large area of & mountain range.

When the metamorphiMiu has proceeded eo far that the miens huve been decomposed, so as to liberate the tuaguesia by the absorption of water, we have a series of rocks all of which are oharucteriaed by a smooth, slippery, greasy feel to the tough, commencing with talcose scf}ids, of a greenish or yellowish tint; inclin- ing to reddish from tbe decomposilion of the minerals containing iron. On further cbnnge we may have mheitos, forming in the seams and joints of the rock, or tbe whole mass may be converted into soapstone, which is a compact whitish or greenish rock, without pronounced crystcdline Btructure, easily cut by the knife or turned in a lathe. From its infusibility and the facility' with which it aau be cut into suitabla blocks, Roapatone forma an excellent lining for fur- naces which are aubfected to intense beat

Chlorile-schiats are similar in oompoBitioB to taloose schists, hut ibe talc is replaced by an apple- reen mineral called chlorite, which not infrequently occurs along with quartz in mineral Teins, ae on the mother loie in California and elsewhere.

Thia series of rock i may be thus summed up, on two lines of progressive alteration, acoording to the start- ing point:

(1) Sands, saudstoneSj quartzite; (2) muds clay&i ahales, schists, gneiss, ayenite or granite.

rnospiaCTmo and VALumo mines.

Secoseaey Gkqup Fbaqmental Sebieb. — Besides the rooka previoualy described, all of which ahow evidence of depoHition in crater and soinQthmg like a regulai' order, there are still a few vbich cancot strictly be olaesed with tbeia. These are either voleauic or glacial. Volcanic Products. — Volcanic outburets are often acoompauicd by the diachEtrge cf euormous quautitiea of dry duat and stonea, aome of which arerouDdedaud others angular, or the dust may be an impalpable powder. Some of these may have been deposited under water, 'when tbey naturally have a distinct strat- ification; while in those laid down in the open air this structure may not he so ivell defined, though the alteruatii]g cbaracterof tbe material ejected may have formed apparently stratified layers on the aides of quite steap mountaio oancs. The discharges may consist entirely of lava fragments, or may include pieces of all the rocks traversed by the uoloanio vent, and in many caeB tbey have been cemented together by a lava paste. The various conditions in \vhicb tbey are found sug:g6et approprifitfj namee, as ml{:anic con- glomerate, where the pebbles and bowlders are rounded; volcanic bfecfia, ivbere these are angu* lar; volcaidc agglomerate, where there ia a mixture of the two foregoing, UBuaUy without any distinct strati- fication. Tbe finer materials are called tvfag or tii9 aud ae a rule are distinctly etratided ; aud while of volcanic origin may contain organifi remains or fos- sils, equally with ordinary water-formed sediments. The term lapilH is applied to the coaraer portion of the Tolcanic duet, so largely ejected prior to the ap- pearance of lava at many volcanic vents, to distinguish it from tbe finer volcanic ah, which may be a powder 80 fine thiit can be carried hundreds of miles by tbe wind before finding a final reBtin place. This finest ash forms a large part of the sediment brougbfc up from the floor of the deep sea, where it gathers as slowly tmd silently as dust in a deserted room.

nOCK-FOBMWQ MINEUALS AND ROCKS. 67

Glacial Products, — While all the material dis- charged by glaciers into rminiug stieams is undiafcin- ijujfihable from other sediiueutary deposits, those dropped by meliiug ice preaect only faiut trnces of sediioeDtatJon or iioue at all. Where lloatlug ice la dropping; its load of earth, saud, gravel, rounded boTf]ders and angular fragmentB, on the top of strata which ara forming under the surfaetj of laikeE or sbaU low seas, vte may tiud immense bowlders or bumiheg of graTftl irregularly niissd with such dejiosita, which, while they betray the condition of the climtita at the I>eriod of their forixiationj do not justify any special name to aucb accumalations of sediruent. But where the glacial deposits are laid down by ice in deep waters, where the deposit of river or ocean sediment is forming very slowly, we shall have an irregular ao cumulation of material, without the regular stratifica- tion of river deposits, showing only what may result from the more rapid descent of the largest pieceB, which, if they fell on a surface already smoothed lay the more slowly descending liner sediment, would pre- sent faint traces of sedimeutatian, but the lines would not be traceable for more than comparutivey abort distances, the succesaive deposita fading out laterally and overlapijinjg each other. Such also are the d6~ posits of bijwlder day which have also been formed by the grinding action of an ice sheet. There ia nothing to prevent such deposits carrying ore, except the irreg- ularity in their compoBition on account of the wide area from which they may be drawn, and the uncertain distribution of the valuable metals iu the earlier rocks.

GfiOLooic SuccESsiois OF EvESiB.— It is scarcely with- in the scope of the present volume to enter into a deacription of the geological succeesion of the rocks, AB it would require a volume by itself and he of little practical value to the miner, except as regards coal and iron, the character of which ia largely influenced by their geologic age owing to the changes which

6S FROSPEVTIe AND YALUINQ MINS8.

bavo taken plaoe m their oompoaition 'witL the lapse ' of time under the influence of heat and pressure.

The acoompanying; table grlTes the outline Bcbeme adojited by the V. S. Geological Survey. The pro- jfreeeion ia from the bottiom upward, the order beiuyr as eho'TCn in the stratified rocks nuTvaccegsible, though the whale Beries does &ot appear in any single locality. Below the Archstsan is the granite foundation. *'Era*' and "period" relate to time; "system" and "group," to the rocks. Subdivisions of periode and groups are called "epochs" and '"iormationa" (according to time and I'ocks respectively). The names for theae smaller divisions vary in different localities, and authors differ in classifying and naming tbeni, so that a more oom- pletfi i>resentation here would only he confusing.

Order Of Succession Of Geologic Time And Sock. Forma-

Tion.

Em or Syttem, Period or Grovp. Em ot Kaa Quaternai?.

( Plioceof, Cenozolc cP'rTertiarT oi MioceDC

( Eocene.

(Triftssic rPermiaji, i Carhon'itnnaa.

Fidfflozoic i DflVDalAD.

Siluxiaxi. (.Cambrian.

Arcfiffitui J Haronifts.

[See also tbs omulmeDt proponed by LeConte and Dana, pp. 332, 823.]

Chapteb Iv.

Physical Oearacteb Of Mineral Deposits.

Muterai. deposits may be roughly clBBsed uncler three heada : Bedfl, veins and raasees. These divis- ions oorrespond to differentiGS in form, and, in part, to diflereaoes in origia.

Beds. — A large proportion of the rocks met viith Consists of BiibBtaDcea arriLuged in distinct gtratiiied layers. If any of these layers aousists of a useful mioerat, or coiutains enough ta make it valuable it is said to be ft deposit in the form of a "bed," "aeam," or ''stratum/ aoifietitnea spokeu of as a "bedded vein** or'* blanket vein.** The moat important of all bedded or stratified deposits is coal; bnt in addition there are beds of iron ore, copper-bearing shales or elates, lead- bearing sandstones, silver-bearing aandbtonea* gold, tin and platinnm-bearing gravels, as well as beds of rock salt, clays, slates, linDestcuEis, gypsnin, oil abales eto. The chairacteristio feature of a bed is that it ia a tuember of a series of stratified rocke, and rb such was laid down or formed after the rocks on which it rests, aud before those which lie on its top. This peculiarity at once distinguitihea a bed from a true vein.

R'jof and Floor. — The layer above it is called the *'roof"of the deposit aud the one below it the"floor," whe it remains horizontal or nearly bo, but 'hen highly inclined the terms "hanging wall" and "foot- wall/* appHed to true veins, are equally applicable to beds but less expressive.

2?iickm!s.—Thia ia the distance from the roof to

SPECTING AND VALUING Ml

the floor at n'ht angles to th& inclinatioD of the floor, being tlie ahoiteafc distance between the roof and floor, aud this Eaay be vary much Jess than the length of a croascut run through the deposit on a horizontal line, the two bacominc nearer in length as tb© bed ap- proaches more find more to the vertical; in the latter caee they would be equnl.

Dip IB the mcliaation of the floor from a hori- zontal plane, and may be apoken of either in degrees of a circle, as for esample ten degr&es (10°) ; or ex- pressed in feet, as 1 in 10, 1 in 20, etc. Other equiva- lent terms are "slope," "pitoh" "underlie" and "inclination." Dip, of course, ie due to the disturb- ance of tbfi cjeposit byeloTation or depression, flnusing tiltiDg: or beading, aincB ita formation (a horizontal layer having no dip); but as such disturbance baa been almost universal, nearly all bedded deposits b&ve more or less dip, at the present day. Sometimes the beda may be nearly horizontal, as in Staffordshire. England; orraisedtoan aule of 50° aa in the Cumber- land coal seriea in the Skagit Talley, Wash. {pi. 2, fig, 10); sometimea they may be vertical or even folded over as in pi. 4, fig. 6, a structure which is found in the Appalachian mountains, and in some of the Franco- Belgian coal fields, where a vertical shaft passes six times through the same bed, because the folding has been ao complicated.

Strike. — The strike or courae of the bed is the di- rection of a horizonSal line drawn along the floor of the deposit, such as the bottom of a tunnel folloTving the mineral, without grade. This direction will clearly be at right angles to the dip of the bed, and will consequently vary ag the dip varies; so that, if it ia desirable to run a tunnel on a deposit in a perfectly straight line, it must have a course or direction as nearly as possible at right angles to the general dip, instead of to the dip at any particular localiti'. But thia is not alwaj's possible.

Physical Cbaragtbr Of Deposits.

From the above it will be clearly seen, by referenae to ph 13, figa. 10, 11, 12, 13, that while in tig. 10 the strike would be east, in fig, 11 it would Tary from northeast to east atid thence to Boutheast ; in fig, 12 it would be north, going tound by east until it waa BOUtb; while in £g 13 it would turn to all points of the compuas iu succesaion and iudiciitea aaucerebaped basin. From what has been previouBly said it will be obvious that even when the bed may be covered on the surface its positioci, if it esiiBts beyond the point of discovery, should be traceable by tbe rocts with -which it IB aBSOuiatedj but a search in this manner should be governed by the rock which forme the roof, BB this must lie comformably above it, while it is pos- fiible that the deposit may lie on the upturned edges of a great variety of rocka as at E, ph fig, 1.

The thickness of workable beds varies xvitbin verj- ide limits according to their riubness in sone special mineral or its scarcity. Some workable beds of coal ore only 1 ft. thick and range up to as much tiO ft. or over in eiceptional cases. The copper-bearing ehales of Mauefeld are only from 10 to 20 in. thick, while the lead-bearing sandstonee at Mechernioh are no less than 85 ft., aud some beds of slate, limestoDe and salt greatly exceed tbcBe diiaensione. But what- ever the thickusBs may be at any particular point, it dues not follow that this will be maintained over the entire area of the deposit. Sometiines this may be the case over a very extensive area, but there must neoee- earily be e boundary to the depoeit in all directions, and toward these limits it may dwindle away to a feather edge with the probability of the greatest thickness being near the central portions of the orig- inal deposit (not necessarily that part left to our inspec" tion). Toward these edges, aa in the case of coal and iron deposits, the bed may contain many impurities and become valuelesa; or iu the case of slates and Umeatoues a gradual change may take plaae into

PSOSiECTmB AND YALZTmO MmE8.

another kind of rock, sucli as cjaj'-shales into sand- stones and these into congloiueratea. PI. 2, fig. 1, fiow9 a bed of tiodX, aB origin&IJy laid dowD, tiimning out in all directions. It may consist of a uniforna mass, Tvith impure edgings or it vi&y be divided into several layers, by tLin sheets of clay or waste matter, called "partings/" in which case it often happens that the character of the coal aboTs a parting is different from that below in important particulars, attd should bo mined separately. Partings are not neoessarily a detriment to a deposit as they frequently facilitate ruining.

Outcrop. — It is not always eaaj' at first sight to dia- tinguish the outcrop of a bed from that of a true vein, but it will ufjually be found mora continnous and more uniform in its composition.

Yeins may be described as comparatively thin aheeta traversing what are called "conntry rocks," which were formed e&rlier than the veins theinselves; and occupy crevicea formed by fracture of the inclosing rooks, or have been formed along the lines of junction of such rooks by changes in those adjacent. It is this origin at a later date tban that of the rock formation which constitutes the essential difference between a vein and a bed.

jDilces. — The above deBcription includes all veins of porphyry or other iutruded rocks, such as granite or basalt, fts well as thoso containing the useful or pre- cious minerals. Veins filled with porphyry or similar rocke of whatever kind are usually called '*dikes. "

True Veins. — The term ' ' vein" is more properly rsatricted to those which are more or less filltjd with useful minerals, whether in workable quan- tities or otherwise. Building atone should be Gieluded from this definition, as many valuable varieties (besides those found in beds) are the prodoft of dikea, In the United States the terms *'vein/' "lode/* "lead" or 'ledee" are used indiscriminately in different

Pmtsxcal Character Of Deposits.

localities, but aU have the same meaiiiiig: \vlijle id Australia and South Africa the terca ''reef" ia often applied to mineral 'veins as well aa to bedded deposits like gokl-beariDg conglomerates. For the purpasesof the U. S. land oificea the deacription of a lode as given by JuBtioe Field in the celebrated caHe of th@ Eureka Cons, vs, the Bichmond Co* is accepted viz. ; "We are of opinioDj therefore that the term [lode], as vised iu the acta of Cougreas, is applicable to any zone or of mineralized rook, lying within boundaries clearly Beparating it from the neighboring rocka." This. definition evidently aoTeiB both true veins and all bedded deposits.

Mineie often speak of coal and iron veine, but this ie a miBapplication of the term. When a bed lies an the upturned edges of much older roeks, as Id pi. 2, fig. 1, E, it sbowB oonclusively that before ita depodtion long periode of time had elapsed, in whioh the lower strata bad been raised above the water, uplifted into new poaitions, vfova dowa to a new surface and again do- pressed below the water level] and we can form some comparative idea of the relative ages of bedded veins by the thickness of the strata which liave nccumulateil ' above tbetu. In the caae of true veins we can ouiy judge of their age by knowing that they must be younger than the rooks in which they lie, and the comparative age of tb€se is judged by the fos&il rnaina found in them.

Dip. — Like beds, veina have dip, strike and walla. As a usual thing the dip of true veina is apt to be steeper than that of the majority of beds, though auch a distinction is not absolutely necessary. The dij) is meaig'Ured from a horizontal line as in the case of beds, and is sxpreaed in degi'ees. If the vein is vertical the dip is 90°. In pi. 9, fig. 1, the veioa A, B, C, and have respectively* dipsof 47'', 68' and 86', while vein E 18 vertical (90'). In some cases the dip may be so flat that when the vein is exposed by the wearing away

PHOBPOrnfQ ANJ} VAL UWQ MINS8

of the hanging wall it may appear almost like a bed. Such caaea are often ternied "blanket-veiES," but a very alight examinatiaa will show, in moat caaes their true origin.

Strike-, — Owing to their different origin, the strike of trueTeins is more likely to have a uniform direction than in beds as the inclosing rocks have not usaally been Bubjected to so muob movement aince the forma- tion of the fissure ad has been suJ£ered by the strata containiug the beds; or, if moTenteit has taken pUca, the wenkness of the fisaure has directed the motion into that plane and simply oauaed a reopening of tho fisaurej and not infretiuently a refilling of H with a different cIhs of mineral deposits. See pi. 6, Bg. 6, where the thin slabs of rich gold ore 5 occur on each side of a large central core of poor or barren quartz A. The oouclugion is equently irresistible, taking into oonaifleration the great amount of motion of the walla of the lode as shown by their shattered condition, that on a reopening of the fissure the oontenta of the lode were concentrated in the w&y shown, to the im- pOTeriahment of the main body of quartz.

Outcrop of Ffiits.— The Outcrop of a vein, sometimea called "croppings," ia the portion of the vein espoaed on theaurfaoe. It does not follow that the visible out- crop florresponda with the true strike of the lode. This flan only occur when the vein is vertical, or out- crops in a level plain, when it would show a compara- tively straight line and the true course, whatever the dip might be. It is not often that auch a case occurs. On the contrary we find the bulk of mineral veins in rough and broken mountain regiona, and in these caeea the tracing of the outcrop beaomea a more di£Scult matter, espeoially when the vein crosses ravines or val- leys filled up with gravel or debria which hide its presence. All veins with A pronounced dip have a crooked or serpentine outorop, and the Hatter the dip the more aiauouB this outcrop will appear. By refer-

PHYSICAL OBABAOTEn OF 3EP0SITS,

n

Gjice to pi. 9, figs, 1. 3 and 5, these reculiarUies will be easily underatootl. Tbeir great imiiortaDce be- comes apparent when making: locations oB a Tsin and Id the legal aspect of these loc&tioiiB. Fig. 1 is a ioDgitudiua]! section along the bed of a ravine ehow- ing tivG veins -d, i?, C, D, E, and their outcrops ascend- ing tbe bill on the side furthest from the observer, as from f7 to Sj A to r, k to p, I to o, and jre to n. All the veins are supposed to run north and south. It is e-vi- deut that on the crest of the ridge the outcrop of tbe Tein dipping east, will be west of its position in tbe giilcb by the distance while in tbe cases of the Teine C, B, dipping west, the oatcrops on the ridge will be east of the position of the veins in the bed of the gulch as shown at fc and by the distanoea-frr c]}, and do. It can also easily be seen that on de- scending the opposite side of the hill, the outcrop of A would awing back again up the ravine, while all the others would swing down, producing, if the outcrops were continuous an appearance sometblng like that iu tigs. 3 aud 6. In tii. 8 we have detaits of the out- crop of two veine J?, _fl, and 0, 6', running north and Boutfa on the two sides of a ridge, and both dipping to the west; and in fig. 5 siniilar details of two veins yi, and A A dipping eaet. The outcrops in fig. 3 are shown by the black lines A, A, and A A and in fig. 5 by the BiMilar lines A B, and C, C A little study of these figures will make the juatter clear, without elaborate de- Boription. All the peculiarities of the outcrop may be illustrated by takings large sjuooth potato, and cutting iiinto halvealengthwise. Lay the two halves' fiat side down on the table side by side and we have two minia- rture hills with a ravine between them. Now if a cut be aade serosa both hills inclining from right to left we 'shall have a vein in tniniature, and if the pieces be drawn slightly apart so as to show the white of the inside in contratt with the brown skio, the pale line thus madfi visible will indicate the outcrop of the

vein, &nd will be found siniiJflr to figs. 3 aod 6. By zuakiDg the first cut fiat anH Bubbequeut oqgb steeper the gradual approach of tbe outcrop to a straight line ae the view becomes more and more vertical will be quickly apparent, until the vertical cut will represent the vein E in pi. 9, fig. 1.

Tlie outcrop may either be a very conspiououe object standiBg many feet above the enrrouoding sur- face or barely visible on the hillside; it maybe merely outlined by a sijrface depression, or form a deep gorge, according to the relative hardneBS of the vein matter and the country rock, or the difference in the oontents of the vein at diEPerect points in its length.

Dikea, which have a nearly uniformi composition throughout their length, often traverse a country for miles, standing lip like ruined walls, as at the Devil's Slide in Utah, on the Union Paoifio railway, and at other plfloes which nearly every traveler can recall but such uniformity very seldom exists in mineral veins. On the mother lode of California the bureri portions are largely made up of threads and atringers, Nvbile the valuable portions consiat of jmineuse bodies of solid quartz, wbioh Lave protected the present bills from -wear and tear, while the ravines have bean cut out alongside the lode (pi. 7, fig. 6) or through the barren portions at right angles, or nearly so, to the vein, as in pi. 9, fig. 7, where AA, represent quartz bodies; B, the barren iutermodiate ground and c,c, the visibJe outcrops. This structure is continuous for many miles. In Mariposa county especially the heavy white quartz crops out from the eresta of one hill after another, orossing their summits like the comb of a helmet, in a most conspicuous manner, with deep intermediate ravines. In these cases the ravines are due to the absence of ore in the outcrop, but in other casea the ravines are due to the presence of soft, friable, easily decomposed ore in the lodefl, 'orm along the veinSj in gorges of varying depth aooording to the

Peyswal Crabagtmr Of Deposits, 77

dogrr of difference in hardDea between ttB lode and ita wall rooks. A good illuBtratiouof thiH strucfcure is found in the Monte CHsto district on the west slope of the Cascade range in Washington, where the abrupt bluGfs forming tbe walls of an ancient glacier baaiu, are furrowed with deep, abrupt t;;orgaa, similar to pi. $f fig. 6. The reins here cut aaroBs the elates with a dip of about 60°, and haTing undergone extenaive alteration, besides being mineralized with friable ores, fire now softer than the metamorphie elates, so that as the vein wore away tho overhanging wedge of roflk B, broke off from time to time, leaving a steep dope to the footwall aide of the ravine, and a nearly vertical bluS above the banging wall, from which large frag- ments are annually detached by the action of frost and Bunshine, widening the ravme, while at the same time the melting snows deepen ita bed along the course of the vein. In auoh oases the foot of the blufEe ia cov, ered with an immenfie "tfilua*' or broken rock slope, consiating of anguliu* frost -detached fragments broken from the olifif above, which have buried the outcropB in the lower portions of the valley, roughly indicating their poa.ition, however, by wiurowa of immense bowl- ders which have been datachecl, for want of support, from the overhanging wedge B, aiid have rolled down the slope without being more than partially broken up in the fall.

In other caaea the Lardnesa of the vein matter and that of the incloaing roek may he ao nicely balanced that they both wear down at about the @ame rate, and the oroppings may be covered with earth, etc., or aa the prospector gays, "blind;" that is, hidden or hardly visible ; or the vein maj- become blind because aince the time of its formation new atrata or volcanle over- flowa have been laid down upon the containing rocka, && in pi. 15, fig9. 13 and 14, which ahow such a case in longitudinal and orosa section. In this case ii ravinea ha7e out down through the "cap-rook" the

Tela may be seen oroppiug on the side of the ravine &b at Af fig. 13, "being loat uuLler the cap JS, but reap- pearing at Con the other gic3e of the hill.

This cap may be eitLer Bedimentary or eruitive rock, or it mny be Ihe cousoliJated enow (nere) of a Buoweld both fortDB being aeen in the Monte Cristo riegfotii BU thiit the impocttmae of determining accu- rately the strike aud dip of therein, so as to recognize it on both sides of the mountain, becomes very appar- ent.

But in whatever manner the outcrops may occur the same rule will generally bold good for quite an exten- BiTQ district or group of veins, and a recognition of this fact may save the prospector many a weary mile, of travel and bard climbing.

If the vein has a very tiat dip and is Jocated on a more or less conical hill, it may even crop etttirely round the somruit of such a peak, aa shown in pL 7, fijs. 10, 11, m -which fi. 10 i& a vertical aection and fig. H a ground plan of the Banie. We have here a aeries of trap dikes with bedded nunrtz veina lying between granite and slate. The drawiny;a represent the Yauderbilt mine near Silver Peak Nevada, and show a similar atructure to that of the Tyndall mine in Colorado.

Spurs. — Jt not infrequently happens that a vein pre seute more than one outcrop, the main lode preaenting itself at the surface with several minor lateral branches, as shown in the cross section of the Dol- coath mine, pi. tig. 1. These are generally more numerous on the hangius wall side of the lode, and present in the greatest numbers when the dip of th© vein is flat, as was the case in the Comstock lode, of which a general idea is presented in pi. 2, fig. 2. These 'spurs'* may ruu nearly parallel to the main lode, Bnd standing more vertically unite with it in depth, or they may run out into the general beddint: of the rook, as Bhown in pi. G, fig. 2, jss.s. In the

PHYSICAL CEARACTMR OF DEl'OSITS.

former osbb it is easy to uBderstand how the cracks in whioli they are formed were made by tho weigbfc of the overhanging wedge breaking it across from time to time, or the sliding of the hanging wall on tho foot- wall pulling it apart, a cause which might al&o give rise to the epurs which braiich out into the bedding.

Hora.es. — In other caaea, especially in very large "veinH, these spurs after leaving the vein may reuuite with it in all directions, resnlting in a mass of barren xock entirely surrounded by veiu raatter, to which the term "horee" is usually applied. Thesa are fre- ctueutly spoken of as masaeB of rock which have fallen into the liasuro, but they hove usually moved but a Tery slight distance, if at all, from their original poai- "tion.

Walls. — "When the vein is vertical the walls may be iistinguished by the points of the compass, aa the north, south, east or west TFall, but when the vein hna a slanting dip the lower wall ia designated as the "foot wall" and the upper aB the "hanging wall/' as in pi. 7, fig. 7, where the granite forms the foot wall, and the slates? the hanging wall of the quartz series B. In England the term 'cheeks" is Bometimef? applied to the ft'sUs,

Gouge. — Not infrequently there occurs between the vein matter and the country rock a ficaixi of clayey uiatter called "gouge" or "selvage,* which may be of extreme thinnesa or reach a thickness of as much as 30 ft, as in the Potoai mine on the Crorastock lode. Tbia IB appareutly the result of a grinding or crushiug movement of the walls of the vein upon each other, Qncler enormous pressure, and where a portion of the ein has been mixed with material from the walls the goiage is often rich enough in mineral to go to the rediiction works. Mine clay may also result from cheiuieal decomposition of the wall rooks.

Slickenmdea. — Where the motion has been oonsider- , aad the walls or vein are hard enough to resist

80 PROSt'EGTING AND VALUING MINES.

the grinding actioD and reduotiom to clay, both the vall and the Tein matter beoome murked witli paiallel lines or strice, called "slicJieiiBidea/' or 'sliokens," which iDditiBte the direction of the oiotion and fre- quently the quartz or wall Las taken a polish equal to anythiag which can be produced artificinlly,

Ffozeii' Veins.- — In other cnsea it may happen that tbeire is oniy one well deSned wall the vein mat- ter being firmly attached to the other, and gradually fading out into the barren country roflk, as shown in pi. 6, fig. 3, where C, 6', may be slates or any other rock; A, & dike outtiu tbe game, nud B the ore Tein with a well daficed on the right hand but "frozen" to thei dike on the left side. The condition of thd walls is a matter of much interest to the miner. If the ore ia frozen to its alls on both Bides it is almost a positive indication of uncertainty of continu- ance in depth, but heay claj' aeanjs or gouges are taken as favorable indications from the evidence they supply of a deep-seated fitisure.

Vein Ma.tler. — The material with which the vein ia rilled !b known as the "gangue" or "flaatris," usually by the former term. It is not neceasarily quartz. It may be limespar (calcite, c&) duurspai-, barytes, or even the decompoaad remains of a porphyry dike. The term matrix alludes to the filling bein the mother of the ore. It does not follow that all this ijangue carries ore, or that it is of uniform thickness through the entire length of the lode. Th© movement of the walls may have brought two swells opposite eaeh other, as in pL 6, 2, at -Sand in pL 2, fig. 9, and the vein is then said to "pinch" or "peter out;" or the ore maj' be confined to slabs on the walls, as in pi. fi, fig. 6, where B may represent ore and A the barren auartz gangue. Fig. 5, on the same plate, ia an exaggerated representation of a condition fre quently seen in the softer kinds of granite where instead of the vein pinching completely, as in g. 3,

Physical Cuaracter Of Deposits. Si

the motion since the vein was filled with quartz (black) has been able to reduce the partions of the wall rook between the swells B, B, to a condition of gouge or uearly sOj and a new wall has been eBtabltahd as

Ore Chutes.- — It tao happen that all the gangue or matrix is charged with ore, but thia is seldom the case. In the majority of cetaes there are wide and lon barren spaces in the lode ood the ore is con ce nitrated into 'chutes" (also spelled 'ahoots"), aa shown in pi. 9, fig, 7, A, A, ThesG may vary greatly in ditwen- sioDS, being sometinoes ao short b or iioii tally in iiro- portion to their leugth that they are called " pipes/' Id addition to the dip which they have in oominoD with the vein, they have an inclination to th right or left of a line drawa on the dip at right angles to the Btrike, which bis called the*'rake." For inatance, looking down an ioclioe ou the vein, the ore may go off to the right or left of this incline, and this feature ia usually cominon to all the veins in a district which have the same strike aud dip, and the rake is usually the greatest in the flattest veins. In pi. 9, fig. 2 (a cross section) shows the clip of the vein, and fig, 4 (a longitudinal section) the rake of the ore chute O, which is estimated from the true dip line, in this case 37°.

Mabseb.— Under this head are included irregular deposiiU which cannot be classed as either bede or ToiDB. Their forms are various and sometimes they are merely' indefinite impregDations in permeable ground, leached out frotn dnely disseminated mineral in the surrounding country rocka. Some iron and manganese ore bodies, formed in troughs or cup- shaped depressions, are best describttd aa 'iuasees/' as also are ruuny segregated deposits of tin, copper, and silver ores. The most pronounced type is perhaps to be found in the large isolated bodies of lead and zinc ores in liinestciie. Small deposits, of whatever min-

83 R08PEGTING AND VALUINa MINES.

eral, are called 'pocketB*' or "bunohes." The main oharacteristicB of maBses are irregularity and iBolation ; but these do not prevent their being, in many instances, very valuable. If their shape is decided in any direc- tion, they may be said to have strike, dip, rake or pitch, roof and floor, or walls, eto.

Chapter V.

Origin" Of Veins.

All Teina of -wbatever kind, -wiiethBr beariDg Talua "ble minerals cr not, are the result of luovemQuts in the upper portions of tbe earth's crust, producing crackg or crsTices, which have been siibaequently enlarged and tilled Tvith jsom© uiaterial different in its physical and chemical qualitiea and appearance from the rocks ill Nvhicb the fracture has taheu place. I These movetaents, -vvhicli may be the result of earhb' quakes, or the reudjuetmeut of the pressure caused by the thinning of one portion of the crust by denuda- tion and the thickening of another portion by the deposition upon H of all the material brought down from the mountains by the action of rivers, are inti- Diately connacted with the process of mountain build- ing, and consequently show themaelvBB most strikingly' in mountain reions in which also volcanic agencies taTe played a most injportant part,

Fis3UaE3 AND Fat7ltb. — Such fractures in the rocks ffJien they have been accompanied with more or less iictiou of one side of the mass upon the other, or of woth on each other, are kno-wn as "fauUe" or disloca- "ODB, They niaj'" show themselves onl' by a mass of wokeii material or the break may be comparatiTely Iftsn cut, and may be i?eiy short or exteud for many toilea, as in Iew Zealand, where one eartbquate (1845) Jiodticed a fissure in the southern island which aver- IS in. in width and was tiaceable for a distance

Prospecting And Valuing Mines,

of 60 miles parallel to the Bxea of tbe mountain chain, wliile the earthquake of 1855 gave riee to a fracture which could be traced along the base of a lino of cliffs for 4 distance of about 00 milee.

But whatever the cauee and however lou tbe fissure Tjany be, it must terminate at each end Romewhere, otherwiae it would cut the world in two; and it ib evi- dent that however great the elevation or dejjreesiou of the bounding wuUb at anj one point, there can be uo Buch uioiion at its two extremities ; and that tbe grinding action of tbe motion, which preparee the fis- sure for the fotnintion of a mineral Tein, must be nothing at either end, and gre&test whei'e the displace- ment of the walls has been moet extensive.

It does notj however follow that all fisBures will produce mineral veiua, fur there must be a combina' tioD of circumataucGs to muse such depOBitions; but as these Jaulta may have heen and often have been, formed subsegueut to the formation of bedded de- posits auoh as those of coal, iron or gold-bearing gravels, it is therefore necessary to know Bomething of the features which these faults present to enable ub to ogain find a broken bed or vein when lost in the cGUT'se of workiug.

Throw, — The HimpleHt fmni of fissure is shown on pi. 3, fig. 4, A B, ivitb tbe greatefit motion at n,o; CJ3 in the name fifcCuro (after Geikie) ehowe a fissure Split- tiug at the ends iuto mioor branches, the amount of "throw" or digplaeemeDt of the walls being given in figures, which indicate the greatest movement in the middle, as before explained ; while £i shows one in wbioh the walla have been drawn opart at right anglee, or nearly ho, to the main fissure, forming "spurs." A similar structure is shown in id, 6, fig* 2, InCD, pi. 3, fig. 4, while the greatest total movement has been say 30 ft. it does not follnw that all this movement was on one aide of the fissure, for one side nay have been raised and tbe other depressed in varying proportions.

J

oniGiN OF vEma.

S5

Theee figures are horizontal plans. PI. 1, figs. 3, 4, 5 G, show the Bimplegt kind of fault in vertical croae section if the break were an abeolutely etraigbt Itne which, however, is liot often, if over, the case. Fig. S showB n fracture iu a series of bed(l€:<l rocks without any apparent displacement although it m possible tbut there might have been such horizontally. Figs. 4 and 5 show a movement of either or both of the two wal on eqch other in the direction of the arrowheads; but there would be nothing in Huch a case, as the fracture is clean cut, to indicate the directiojj in which the movement had taken place, whether the foot wall had been depre&Bed ae in lig. 5 or elevated as in £g. 4, or the revarfle in the case of the banging walls; but in fig. 6, 7, the movement is clearly shown by the bent and broken edges of the Btrata to be an ordinary fault or depression of the hanging wall in fig. 6.

Jieuerse Throw. — Elevation of the hanging wall (or depression of the foot wall) is shown in pL 1, fig. 7. Such a throw is also seen in pi. ll 5, from the gravel pit at Laporte, Cal. The direction of the throw ia called the "hade."

Pockets Fanned by Faulting,— 11 a fault instead of being a clean, straight cut, has a sinuous or wavy form, as in pi. 2, fig, 7, the reewlt of aotioa of the walls in the direction of the arrowheads would be very diSerent. producing the form shewn in fi. 8, or a vein of very uniform width throughunt, if the move- ment were a mere separation horizontally ; whereas, if the moTement bad been in the direction of the arrows in fig- 9, the swells of one wall may have been brought against the swells of the other wall resulting in a aeries of lens-shaped pockets, especially if the course or strike of the lode be also sinuous and it has suffered more or less longitudinal as well as vertical displace- ment. On ainking on the outcrop at a, fig. 9, the vein would be found widening rapidly, forming what the Mexicans call an "A" vein; while, if the surface had

R08r£iGTINQ AND VALUING MINES.

been worn fiway to tbe dotted line 6c, similar sinking would reveal a vein rapidly dliaiiiiibbiug in width or a

Very rapid widening of an ore body in this way ia liable to accompaiiied by an equally rapid contrac-' tion, aod vice versa. An easy methoci of getting a thorough underatauding of this important phage of iiBBure structure is to tear a piece of paper in two lialves alon a wavy line Bucli as ie ehown on pi, 2, fig, 7; when, by moving them apart in various directiouB upon a dark background, every phase of the question can be readily studied, particularly if in ono instance the waves are made short and deep, and in another loDg and gentle. PI. 6, fig. 5, 13 an exaggerated illus- tration of such structure to show that when the ore (black) is lost at B the seoi-th for the next eweli must be continued by foUowicg the croBshead or seam which outs the ore body off (this being the original fissure line), and not by following the false wall WW, which haa only been formed by the motiou and pressure crushing the swells of the country rock AB into a shat- tered mass of vein matter; or, yet worse, by preauni- iog that the course of the ore body is the general course of the vein, and foHowiug that direction into the country rock on one of the joints which originally determined the shape and poBition of the ewells on the line of fracture.

Gashes. — "When such fissures have been formed by pressure from below bulging the surface upward as in pi. 2, fig. 4, a, simple gash may have been formed, which wuB later on filled with mineral matter from above or laterally ; or by the aotion of surface waters, became, as we so often find, the line of a watercouree following an anticline e. A sagging in a syncline might conceivably give rise to the opposite efEecfc, aa in fig. 5.

jSVep FoAilis. — In other casas the elevation has been BO great and the strain on the strata so enormous that

OBIQIIf OF VEINS.

'87

when ttey did give way the central mass witli the largeBt base exposed to the elevHtiug force has been thrust furthest ujiwarU, wLil© the masseB on either side have settled down in gradually lessening atepa until the njovement fades out into undigturbed coun- try, producing a serieB of "atep faults/' of which pL 1, iig. 1 IB an ideal and 2 an actual illustration, the latter being taken from the reports of Prof- Em- mons on Leadville, CoL where the drop of 2000 ft, at the Moaquito fault is reduced going westward to ouis' 750 ft> at tlie Carbonate.

Trouijh FauUa. — The faults shown in pi. 3, figa. 1, 2j 3, known bs, "trough faults," are mora compli- cated, and Rre beet explained in the language of Mr. Jukes, who proposed the following eat3sfaotor3' solu- tion of the problem: "Suppose the beds AA, BB, eto., 5g. 2, to have been formerly in a state of tezisiou, arising from the bulging tendency of an internal force, and one tisaure, FE, to have been formed below, -which OD its course to the surface splits into two, ED and EC. If the elevatory force were then continued, the wedge-like piece of rock between these two fissures, being unsupported, as tbe rocks on each side sepa- rated, would settle down into the gap as in £,g. 3. If the elevatory force were greater near the fisaure than further from it, tbe single Assure below would Lave a tendency to gape upward, and swallow down the wedtje, so that eventually this might settle down, and becouje £ixed at a point much below its pre"vious rela- tive position. Considerable friction and destruction of the rocks so as to cut olf tbe corners g, h, fig. on either aide, would probably take place along the aides of the fissures, and thus widen the gap, and allow the wedge-shaped piece to settle down still further. When tbe forces of elevation were witbdrawn, the rocks would doubtless have a tendency to settle down again, but these newly inoluded wedge-shaped and other masses would no longer £t into the old spacea

88 PROSPECTmO ASD VALUING Mil/ E3.

80 that great compression and great lateral pres&ure might then take place/* Ph 4, fig. 5, (after Jukes) BbowB sucli a fault or w>6dg6 cuUing into a bed of coalf which from the enormauB pressure reaialting from the reaettlemeot of the strata ''has beeii reduced to a paste of coal dust and very small coal. "

Very frequently the line of fault becomes the bed of a Tvateroourae auct in time a ravij:ie. This m&y result ' not only from the weaker nature of the rock on tliifl line (as eyidenoed by the faulting itself), hut also froin the tilting of gtrata along the fault plane. Such a fault-formed vaUtej' may or may not at present be occupied by a watercourse. PL 12, fig. 9, eho'a a OBfion following a fault in Death Valley, Cal.

Every mountain region is full of faults, and they abound especially along the great ranges, where the moTomenta have been so great as to bring to the sur- face, alongside of each other, rocka which in the order oE auctiesaion are separated by many thousands of feet; and in these movements vre have an explanation of the sudden change In the character of mineral deposits on opposite sides of lofty mountain chains which some- times seem inexplicable. But almost every vertical exposure of rock in such places as railroad cuttings, and not only of rock but of UDsalidi£ed beds of sand or gravel and clay shows a multitude of minor fia- Burea interaecting and displacing each other, sonae- timee in the most complicated manner, but preaenting evidence of the universality of the process which has opened the way for the circulation of underground waters, without which it would seem that the filling of a portion of the fissures could not have been accom- plished.

There doea not appear to have been any time in the earth's history einoe the first solidifying of the surface when such fracturing and movements have not besn going on, and consequently we find veins of one age intersected and sometimes dislocated by others formed

on fraotureB of Utier date, until in some oases there may result a -very complicated condition, as ahown in p\, 2, fig. 6, wbich a thorough knowledge of the theories of fiiultiug alone can explain, and for want of which loaa and disappointment may ensue from min- iug operationa therein. It does not, however, follow that because one vein may bs apparently faidted and thrown by another, such is always the caae, as at the creasing of AA and CC, where the lisaure A may have jumped along C because the line of least resiat- anoe may have been different on the two sides of C, which would make A younger than O; but where the dragging of the rocks is present, as at the intersection of AA with BB, the presumption is etrong in the abaeDce of other eriduuce that AA has 'beau faulted and thrown by BB.

Slockvx>rks. — The complication arising from these sources may be so intricate that it becomes impoaaible to eay which set of fissures is. of moat ancient date and they mtiy become so numerous and minute that individual miutog becomes an impossibility, and the mass is extracted as a whole, if extracted at aU, under the name of a 'stockwork. "

Eocka vary so greatly in their hardness, texture, oompoeition, brittlenpsa, and facility of splitting that tbey break in very different ways, and this peculiarity must inevitably exert an iiitiuence on the character of the fissures by which they may be traversed, and a knowledge of what may be expected in each case is essential to a clear understanding of the methods to be employed in opening and iivorking mineral veins to £he bt advantage.

"3Vue Fvisure Veina/'— Anyone of the faults shown ia pi. 1, which must ©videutli* eitend downward to an unknown depth, may under certain conditions form what is known aa a "true fissure vein" fan old-time term for what was thought to be the best and most permanent type of a mineral deposit), which is aimjily

m

pRoapsannQ and valuing mines.

a fiBsure, sometimeB miles iu length, coursiug directly fierosH the country iu a more or leas strfliKht Hue, and cutting through tlie rocks iqdiGcrimiuately hut vary- ing in width and character according to the rock in -which it may occur both in length and depth, aud filled with mineral matter other than eruptive rocks-

Strike 'ait/is.— A iault may out the rock formatJOQe at right angloa to their strike or it ruoy run more or lesH parallel with the strike, but cut the rooks on their dip, by being uauUy more nearly vertical than the strata penetrated, -in vrhich case the vein would be formed on & "atdke fault/' and at the surface present many reaemhlancea to -what ia known as a "contact vein."

Effect of Country lioehs on Fissures. — If the iiaaure is entirely in the same rock it may maintain a toler- ably uniform obaracter for its entire length and deptbj but if it cut rocks of various kinds it nuay pinch out almost entirely in those which are tough, expanding iu those which fracture more easily, either from split- ting readily (as slates) or from extra brittleuegf (as certain qunrtzitea). If it traverse a limestone forina- tion it may for a time completely lose the character of ft fissure vein with definite Wftlla, in a comparatively short time after its formation, on account of the ?reat facility with which lime 19 removed by the action of water, especially when containing carbonic acid and the irregular cavernouB structure thus caused.

It therefore becomea an important question when ore is found in a, certain rock to ascertain to what extent that rock is developed, and whether the associ- ated rocks are of ench a character for hardness or soft- ness that a vein, as the miners say, can live in it. The writer has in mind an extensive region where the disregard of these general principles has led to the uaelesB expenditure of large sums on veins which a ver' slight geological knowledge would have taught the miners could not be of permanent value, beoause.

osmm OF vsma.

towGver rich tlie aurfao© orm they were conhained in tlie fragmeDta of a bed of achiatB overlying a tougli bolid syeuite, in which tlie vein esposures were very narrow, and into which the veins found in the achiste would inevitably pass in their lower portions.

If the veia has been formed oq a strike fault, tliere is a yet greater chance of irregularity fi"oni the ten- dency of the break at timeg to follow the bedding planes of the rooks, while at others it cuts through them, resulting in shattered njases which form "LorseB" or barren patches of country rock in the middle of the ore body; or the fracturing may have been so estensive laterally that we have a mass of parallel threads and stringrera instead of a smaller but niore tjonipnct deposit.

Contact Veins, — From euch veins as the latter the passage is easy to thoee formed on the contact of two bodies of rock of different kinds. Such Contacts may he divided into four groups: (1) Contacts between aedimentary rocks such aa elate and quartzite, quart- 2ite and limestone, or eandatone aud conglomerate; (2) contacts between, sedimentary and iutnisive or igneous rocks, such as slate and granite, or lime&tcne and porphyry; (3) contacts between two igneous rocks as porphyry and syenite ; and (4) contacts on the walla of dikea which tu&y traverse a series of either eedimentary or igneous rocks.

When contact -veins of the first two clasaea stand at a high angle or approach the vertical there ia at first flight but little difference in their appearance from ifissure veinSf but as they alwo's maintaLn the same relation to the incJcgin rocks they are apt to Lave a more uniform character both in structure and filling. It ia plain also that they must partake of all the wavy irregularities of shape which have been imparted to the rocks in their upheaval and if followed downward to a BuiSicient depth must eventually flatten ont, as no beds of atratilsed rock can continue to descend toward

PROaPEOTING AND VALUING MINE8.

the center of tbe earth indefinitely, from the "PeraT nature of their origin; still, the contact is usually of grant extent, QDd there is no reason Tvhy the vein abould not be so also.

Thia feature becomee espeoially pronouoced when the contact lies nearly horizontal or only slightly inclined as at Lsadville, because we are able to reacli it "with comparatively shallow shafts over large areas, the e'stent of which in one direction represents the strike of a verticul lode, while the extent in tbe other is practically the same as the depth reached on tbe TertiGBl lade only by deep sinking with all its limita- tions. In such horizontal cootacfc deposits we do not look for horizontal motion, and have only to encounter the troubles arising from subsequent faulting, as in pi. 1, figs. 1 and 2, but in many CAses of steeper contacts there are evidences of vertical motion, in wbich case we shall usually £nd the contact to he local and acci- dental; the lissure being really a strike fault con- tinued to tbe surface on a contact plane which proTed to ba the line of greatest weakness, as in the case of the Coraatock lode in Nevada, which strikes nearly parallel with the axis of the mountains on whose flanks it is located, and presents Tarying contacts in Virginia City Gold Hill, and Silver City, but has been proved; to descend into the syenite at Virginia City, below the level of the Sutro tunnel the character of the ]ode changing at the same time as well as the composition of the ore. Thus evidence of motion in an apparently- contact vein may be taken as prima facie proof that the contact is not continuous, and that the vein really belonsB to the group of fissure veins, and will partake of all their peculiuritiea of structure and'fiUing.

Whan two sediineutary rocks are conformable, but have a nioro or leaa wavy surface of innntion, a sliding movement of one upon the other will give rise to open- ings and pinohca, just as in the case of secondary faults OD warped planes in homogeneous rock, and an

Origin Of Veins,

opportunity for the formatioa of a coDfact yein i& presented, as in pi. 1, Sg. 8. Such a vein might be regarded aa either a eoutact deposit or a jjssure veiiij but is inore naturally coueidered in the former clasB.

As the rocks on the two sides of a contact are seldom of equal bardneas fehe chiavaeter of the vein -will prob- ably be goYeieed by tbat which is inusi liable to decay, removal or fracturing. Tlii is eapeciuU the ease with Blatea and limeatoues, the former on suuoLiut of the faoility with which they split and crush; the latter because they are eo easily dissolved.

GompreiiSion Veiiu. — No person with any eiperi- ©noe in the iQouutaina can have failed to notice the folJe and bends in slate roaka, from gentle waves to minute dumplings, which have beeu produced by foroeB pressing on the enda of the lines of etratiiica- tion, nntil a structure Bimilar to that shown in pL 6, £g. 1, has been reached, a structure which can be easily lixiitated by s;.iuee£ing the leaves of a book to- gether endwise, between the covers, held slightly apart. If such slates are on a line of coutaot, aa at the Keystone mine, Amador County, Cal., and have been eubjected to such pressure, many good miuea baT6 been the result; but where such afition has taken place in the body of a large mass of elate, in the absence of any special uontroUin element such as a dik6> great uncertainty will exiet as to the estent of the movement, which baving full play in all dircc- tiona, may have simply resulted in a multitude of irregular minor foldiuge. In all suoh cases the whole vein does not consist of a continuous sheet of ore, although there may be such at the immediate contact but of ft aeries of lenticular masses, overlapping each other, which may occupy a belt several hundred Jest in width, the broadest portion of one being generally opposite the thin end of another. It is obvious that suob mines wiU require estenaive cross*cutting to make certain that no ore body has been overlooked.

94 Prospecting And Valuing Mines,

Limegfone Cnnlaciff. — In a limeetone contact* wlietber steep or flat, the actual liDe of contact hich will form one wall of the lode inay be oomparatiTGly smooth, while tliut in the limestone miiy be very irregular, depending somewhat on the solidity of the limeatonea or their var.ving degrees of solubility and tbe destruction of the limeetoae by this meuns may be BO complete that the ore body will apparently oouaist of a cemented conglomerate, the pebbles in which are only the insoluble cherty or flinty residue bo abundant in chalk and siUcioue limestoneg.

The remaining groups may be considered together, &a while there may be CAHeB of oontact of two eruptiTe rocks without the presence of a dike, as on the Oom- Btock, the majority of contact veins in purely eruptive rocks are alongside of or controlled by dikes cutting masses of soma other vfLriety as in many Colorado minea. The esBential feature of all lodes formed on the contact at dikes is that the latter have been squeezed from below into the ftsBures bb they were farmed, and that oouHequently their walls must extend downward to the source of the pasty rock with which they were filled and that this source is, in depth, beyond our ability to explore. While auch contact lodes thus present a general similarity to lissure veins in their length and depths they possess one important feature not present in the latter — 'that one wall of the fissure is always of the same composition, a fact which will tend to maintuiu a more uniform oharncter in the filling, at least on one side of the vein. The wall away from the dike will, of course, be liable to changes as the rock of which it is formed varies, but auch changes will be rather those incident to the influence of the heat of the injected dike, as the baking of clay shales into jaspery or flinty products, rather than variations in the shattering of the walls, as the foroing: apart of the wfiJlB of the fiseure and simultaneous filling with a pJssiiG substance would prevent grinding of the faces

t

ORiGm OF ymms. 95

of tlie fisBure agaiDst each other, while Buoh fTAgmenta of the walla as did fall off would be buried in the intruded masa, and carried by it upward on its couree toward the surface if the rent stended that far. lix iiuch lodes we may find a sudden change in the pria- cipal mineral on passage from one rock to another, but u constant admixture of some other ingredient which owes its preeoncG to that of the adjacent dike; the ore on one wall may be of a totally difEerent character from that on the other, as at the Key- stone mine> wh ere, next to the 60-called green- stone hanging w fill, the quartz is massive, white and blocky, while that of the slate foot wall ia handed with numerous parallel blackish lines of slate, making the "ribbon rook'' of the miners; or, as on the Comstock, V?here the nearly Tertiaal ore bodies in the porphyry, as they approach the much flatter syenite foot wall, carry au appreciably larger proportion of gold ; or, aa at a mine in northern Washington, the ore on one wall may be distinctly a silver proposition and on the other, only 15 ft. away, as decidedly a gold one.

In all these cases of dike contacts, the point at which ore will form aud the shape of the depoaita will be governed by the same lEfluencea aa in other con- tacts, whether the lode has been formed by the gradual shrinkage of the masa of the dike in cooling, or by substitution through the circulation of water along ita bounding planes.

Gsah Veins. — Shrinkage of sheets of lava may nlao produce veins which will not extend into the underly- ing granite or other rooks as at the Stonewall Jackson mine, Ariz. Buch occurrences may be claaaed with the 'gaah veins.**

Segregated Veinii. — In other cases, like that shown in pi. 7, fig. S, there may be neither a clean out fissure nor a line of contact nor a controlling dike, but a Miiee of ore bodies arranged along a general line of Bliattering and without definite walla, the change in

PBOSPEGTINO AUD VAL UWG MmE3.

tte ruck becoming gradually less marked laterally until it fades out into the unaitei'dd country rock. Such oocurrenoeB are known as "aegregated veins," by which term it m understood that the mineral has heen concentrated by the action of water into the crevices of n shattBred or eheeted belt of racks from the sur- rounding rocke then]selvea. This "eheetitig" is well Been in mauy mines in granite where an appareLiUy solid and smooth wall will scale off in slabs or sheets, after a short exposure to the air, making it almost im- possible to say where the trne wall maj' he, and ren- dering a large opening nQceBsary to secure a relatively small amount of ore. Many miners make the miatake of considering all the sheeted mase as a part of the veibj thus deceiving themselves with the hope that the ore body may uitijoately be as wide ae the sheeted ror- tioD. A little study will show the falsity of such a notion, as it is quite conceivable that the step faults shown in pi. 1, fig. 1, might be so Duinerous that the spaces between would not exceed the tbicknesa of slabs just spoken of. Mostfaulta through rocks whiob do not break too easily into amall fragments show this sheeted structure, as the result of the dragging of the sides at the moment of fracture. Where there ha been much of thia actioQ we may look for more or less numerous veins parallel to the main lode of a district, which maj' carry more or less ore, but being only inci- dents accompanying the principal disruption are lega likely to afifoTd the conditions which will develop them iuto lodes ofequal value.

General Comcltisioss,— It may therefore be set down as an axiom in mining that as a prior condition to the formation of mineral veins there must have been such fracturing of the rockg aa to faoilitatd the circulation of underground waters vertically aa well as horizoti- tally, and tliat the nature of the fissures thus produced will be influenced by the varying hardnesa, brittJenesB cv solubility of the rocks thus fractured, as well as by

ORIQW OF VEmS.

or

the directiou in which the force may bate been applied. Tka"fil]iug" of the \ein will depend ou other oondi- tiongij but one may reasonably expucit that the structure d veina in granite, for iuatance, will be similar in widely separated txiiulug campa; and so of veias in tough limestone, or easily lissile ahites, and other jharacteritihic rooks; aud we may tnke the geneializa- tioii titili further, aud expect to tiud all the veiiis iu m mitung dietrict, in the sarae rock aad belongiug in the same ayistem, Bimilar to each other in filing as Ttell as structure.

But it does not follow of neceasity that all veins in au}- particular region are of the same age. On the coEtrarj' we frequently find several eysteme, each char- acterized by a general common strike and dip, show- ing that such fegians have been the seat of several &8- sure-foriuiag disturbances, which may have been of 'I'erj' widely varying force, and followed by fillings of ft totally different character; but usually the most strongly developed system will either show a decided parallelism to the general direction of the mountain range, or el:ae nearly atrigbtangles thereto; and, while otieaystemmaj' be a good ore producer, another may be pr[k{!tically valueless. It thus early becomes necessary to identify their peculiaritioa and avoid loss.

hiliB absolute dislucation of the strata or rocka raaj bave been necessary to produce the entire series of Ga lire veins, whether parallel to the strike of the focka or more or laaa at right ungleg to it, simple fold- of the strata may have been sufficient to so far dis- lilac&tbe lines of contact of two sedimentary rocka as

open the way for the formation of contact veinaj or lloaiifar rupture a belt of rooks without actual dia- placement as to permit the formation of segregated reiiis or deposits, or to rupture horizontal beds of t'ffieatone suffieiently to allow the percolation of water Llitouh them, with the consequent excavation of urjfuJai' chambeis.

Prosper

vn VAi

Mines.

These changea are common to all mountain regions and are not uuknowu even m comiiarativeJ.v level cauntrieB, but they have not resulted in the formation of mineral veing in all localitieB. Thera are extensive mountains areas Almost entirely destitute of valuable mineral deposits; andtherefore T\'hile the preliroiEary fracturing of a country is absolutely eeaential to the formation of mineral veiua, their subsequent filling with valuable cantents must be explained by the operation of agencies which were local in their action, and at the moBt very audirectly connected with the agencies whicij formed the original fissures. The frac- turiug of the rocka simply made the formation of the veins possible. The formation of a crevice did not necessarily involve the formation of a vein, but only governed the physioal aspect of such a vein 'whidi formed.

Chapteb Vi

Filling Of Mineral Veins.

Ign&)U8 Theory not Tenable.— It is a popular idea tliftt all iciiiiei'ul veius have been filled from below by tbe luateiial being forced into them wbile iu a inolteQ condition, This would involve intense heat, Vi'"bile tbeie cau be no question that the porpbyrifcic and baualtic dilies h&YQ been tilled in this ujannef; a multi- tude of facts coiDpel us to look for some other explana- tioD for the majority of inetoUiferous Teins.

That the intruaion of dihea has been accompanied with beat is abundantly proved by the changes which have been effected in the roeks throDnrh which they paBB, or into and between which they have been squeezed qs Bbeeta. When cutting through cobl beds or penetrating tbem, as in pi. 5, fig. G (after Jukes), which covers a length of nearly 1,000 ft., tbe coal haa been deprived of its volatile matter and becomes what 18 called ''blind coal/' or is even reduced to a small quantity of blaok Boot. Sandstones become fused into a tclasey quartzite ; elates are hardoiied into a flinty Bub- stance with change of color, while other rocka have become porphjritio, as alongside the great trachytic dike which cuta across Onion Valley in Plumae Coun- ty, Cft], This dike has a width of about SO ft and staiids up as a wall on the hillside to a beigbt of 90 ft. in places, and is apparetitly eontieeted with surface aheete which overflowed from it. The country rock is a blackiah green slate, but close to tbe dike it bas been BO altered as to look like a porphyry,, being spotted

SFECTIIfG AlfD VALUING MIMES.

with white feldspar ory stale, which gradually become leas conspicuous as the vicinity of the dike ia left, until tbey fade out entirely in the plain -colored, unaltered gieneral oountry rock. The same lava ilow contains large fragmente of the country rock which haT© been torn from the aides of the fissure during its fonuation, and altered in esactly the same way, just as we con- vert clay into brick by the action of heat, From these well eetablished fjicts wa would be juetified m looking for similar changes in the walls of mineral veins, if they have been jiroduced in the same way. We do find changes in the wuUb, it ie tiufi, produced, by the action of heat, but tbey are such as result from the action of hot water and gteam, and not of molten inat- ter. The latter when once injected will gradually cool off, and when once cold will produce no further change while the hot "wter may continue to circulate for aes, bo long as the suurce of heat remains ud~ changed, and produce ohangeB much more extensive and more widely disseminated than the action of injected lavas. i

A few illustrations may render the discussion of tbie question more intelligible, and lead naturally to the important inOuence which rocks have on the nature of the vein materia!.

It ia well known that if -we melt copper and silver together we produce an alloy in which the silver is indis* tiuguisliable except by assay or analysis, yet in the Lake Superior copper tnines we find blotches of white silver in the heart of solid masses of native copper or crystallized on the surface of the copper, showing that m the latter case plainly, and in the former by infer- ] ence, copper and silver were deposited in the veiti alternately, some of the silver at least after the forma- tion of the copper had ceased.

At the Head Center mine, Tombstone, Ariz. cryetale 1 of gold are found planted on the surface of horn silver (chloride of silver) yet when melted together gold

FILLING OF MTNEn A L VEINS.

lof

and silver form an alloy with tbe greatest facility, and tbe affinity of the metals for flflcli other is so great that native gold aHwaya contains more ox" Ifiss silver.

At the Alston Moor lead mines in England, irhere galena in a matrix or gangne of Huorsptir is worked, lead crystalfl (gralena) ai'e bedded in tluorspar, with lime QrystalB (calcite) planted on tbe lead crystals, and oryatala of "blackjack" (zincblende) on the lime crystala — four minerals superimposed on each other, one at least of them (inchlende) volatile at a low tenoperature and another (lime) practically infusible.

In tbe Sierra >fetftda mine, Virgrinia City, Wev., a seam of broken rock and clay whioh has been made eince tbe formation of the vein, ie filled with minnte crystals of red oxide of copper, formed by the coppery waters which filter through it from the higher levela.

In the upper part of the waah of Furnace creek, on the eastern side of Death Vnllay, Cal., is a beautifully regular vein of fibrous limestone (satin spar) cutting nearly Tertically through beds of coarse conglomerate, which show no signs of alteration (pi. 7, fig. 8), Fig. 9, same plate, shows quartz veins in tbe same ceigh- borhood and similarly located.

In the ipines at Batopilas, Mexico, native ailver oocure in eics of oalcepar* which have an extraordi- nary persigtence, frequently dwindling down to a mere eeam often less than 1 in. wide for long dietaaceH, and then opening out to a width of several feet. In places probably 90% of the ore ia crystallized native silver, a large proportion of the remainder being cryatallized ruby silver (arsenical) and crTstnllized black sulphide of silver, the latter often in branohiug flakes like moaa formed in the joints of the rock alongRide the veins.

Near Yankee Hill, Eutte County, Oal.f beautiful gpeoimeDS of crystallized gold are found in the joints of tbe porphyries, usually in thin nkca taking the shape of combs, fern fronds, etc. Id this case there ia no indication of veins or vein matter.

303 PliOSPEGTING AND VALUINQ MINES.

At West Point, Calaveras Coumtyj Cal., gold occui in tlie solid granite- At Drytowu, Amador County Cal., gold ocunra in limGtoue; aQd in Mariposa County, near CouUerville, both iu tlie black clay slates and aerpeutines. At Fiddletowa in Eldorado County, gold is found in the iron, pyrites which abound in th slateg. Tba crystals are often of considerable Bie, chiefly cubes, and the gold oau be seen projecting from the smooth faces of the crystals.

It would be possible to extend the liat of similar oaaesof crystallization indefinitely, but it is not neces- sary to u]nre than call att<ntion to the fact that in many casca, if not in all, these crystals are formed ini cavitiea, juuiiy of tbem of such aize an to be oalled caves or caTerna, which are not char acts rietic of any of the dikes which we know to be the result of injec- tioQ from below. Good illustrations of thisforaaatioQ of oryatala in closed cavities may be aeon in the hollow balls filled with qiiartz crystals, called "geodes." The mineracall the amailer eavitiGB fouud in veins *'.TUgs."

Metals also occur in ash veins which must have been filled from the surrounding rocks, having no con- nection with the interior of the earth.

Galena occurs in irreiular deposits iu limestone, where there is no evidence of vein structure.

Chrome iron occurs iu isolated ruassus iu blackish- green hornblende schistR; while platinum, iridium,. Gsnaium, etc.. occur chiefly grains in sHud or gravel deposits, which have probably been derived from ths decay of rock strata, and not from veins, as their occurrence iu veins is unknown.

In the case of the "compression veins" in slates, aa at Amador and Sutter Creek, CaL, pi, G, fig. I, the ore bodies, carryiat gold, are often completely- sur- rounded "with slates identically the same as the black clay slates to the westward of the vein, which show no trace of alteration by beat either as ajiidied by molten lava ox hot water, although they have been 8ubjectedl

Filling Of Mtneral Veins.

to irQCQQnse pressure and hnve been folded in every direction.

1q Cornwall the remarkable oase ogcutb of a vein producing copper for many hundred feet in depth, while anoased in slates {called *'ktllAs"), but chang- ing to tin when it pasBea into the underlying granite, as shown in pi. 8 and pi. 7, 3g. 1, whiah represent a longitudinal section aqd a cross section of the Dol- euath mine.

Again, we have thoe© peculiar veins in which the minerals are arranged in bands parallel to the walls, as JQ ph If £g. 4. This cane is similar to those in wbiob cr.8 of different minerals haTe been clepoaited on the top of each other in euecession.

In pi. 7, fig. Gj we have a ens© in which a hand of rook has been altered, and contains more or less jjarallel ore bodies (shown in black), wiEh uiimeious threads and stringers conneoting them, the whole "stoekwork" fading out into the inploaing rock with- out any positive definition or walls.

Many other cases of interest might be cited, but these are sufficient to show the difficulties which surround the theory of igneous filling of mineral veins from below by injfictioD in the ftirtn of raoUeu or pawty uiattei*.

la the case of the limestone deposits there is no con- nection by well defined fissures wich the interior of the earth, through which the filling could have taken place; and in the case of the Batopilas mines it is in- couceivahle that a mineral so lufneible as limespar could have been injected into fi&stiren, h'equently leefl than an inch in width; while if we admit the possi- bility of the lime being fuaedj, the heat would have been bo intense that the adjacent rocks would have been fused into lava, and the minerals found in the injected material would have heen volatilized and entirely eliminfited, unless retained by condensation ux the cooler surface rocke in which case the ores -fi'ould be found ouly uear the surface and Id the coun-

104 PR08FS0Tm9 AND VALUING MINES,

try rook aa -well aa in the lode, and the latter would be barren or unproductive in depth, which from actuaL exploration we know is not the case. Tbt hat does operate in this way we know Irona the quioksilver Twines of Lake County, Cal. where the surface rocks are filled with minute globules of mercury, which have been brought up from below by the action of hot springs and eteam, and condensed near the surface, where the temperature fell below the yolatilsziiig point of the njercury.

Similar difficulties meet us in the case of the lime vein on Furnace Creek, and indeed in all cases where minerals occur intimately associated with limeBtoue, either in the body of the rock itself, or in the creviceB, or where it becomes the gangue accompanying the ore.

The occurrBuce of gold in porphyry, elate, lime, granite and serpentine, outside of veins, is also inex- plicable on tbe theory of upward injection; as also the presence of minerals in gash veins and the slates of the mother lode in California.

The Bame appears patent of all those oases where minerals are found which readily form alloys and have a similar melting point, in close contact, yet each re- taining its individual character; as well in all caaes of puperimpoeed crystals lining cavities or vugs ia the vein, especially where the cavities are of auch dimen- aioDS aa to become worthy of the name of caves.

That crystals do form in dikes or veins of igneous (or rather of plutonic) origin ia not denied; but they form a compact mass, the various minerals crowding each other to distortion, and mied in tolerably uni- forra proportions, as in granite and the porphyries, in which cavities are almost unknown ; while such crystals as they do yield outside of the mass are found in crevices formed at a later date than the origin of the rock,

"We have-atill the case of the Cornish vaina, which ta only a type of many others, where the imagination can

FILLING OF MmSBAL YEINB.

hardly realize how a vein can be filled from below, during tlie same operation, with copper in its upper portion and tin in its lower, and wby tlie change in the character of the inieoted material should have taken place jiist at the junction of the two rocks which were traversed by the fissure.

In cases as the ocourrence of flakes of horn siWer in the joints of quartzitea at the Isabel mine, near Globe, Ariz.j which can be scraped off, leaving the quartzite abeolwtely barren of silver ; and the same ore in the joints of limestone west of Tucson, Ari., where the surface of the joints gives good assays, while the silver penetrates the blooke of limestone in steadily dirainishing quantities for only a few inches, leaving their interior entirely innocent of ore, we can- not invoke the igneous theory because there are do veins to be injected.

The same may be said of the hem silver found in the Leeds mine, near the southeast corner of Nevada which in many respecte ib one of the most remarkable occarrenees of silver on record. There is no true vein; the matrix or angua in this case is a nearly horizontal bed of sandstone, in which are found large qiiantities of vegetable reniains, auoh as wood, twigs and Jeaves, and it is these which carry chloride of silver in quantity sufficient to make working oi the not only possible but profitable. In this case there cannot be a suspicion of injection.

More doubt bangs over the silver ores in the trachytes or rhyolitea of the Calico district, San Ber- nardino County, Cal. , which occur in the crevices of a truly eruptive rock ; bat even hero the ores may lie in fissurea formed subsequently to the eruption of the trachyte.

We are thus compelled to look for some other method by which the fissures, now called veins, have been filled with their mineral constituents. Among those familiar with the subject the ignoous theory

106 PRoaPEorisa anb VALuma- mines.

which bald sway for many years, haa been generalljr abatidotied sb iticapabld of explamiug: the grfi&ter poi- tion of the pbQomena.

Aqueous Tlieory. — The diBtributian of ore iu Teina ia of the moat irregular obaraoter. In Bome of the gold veins of CBliforula the metal ia colleoted In -well- defined pookets, oontaining all the \Tay from a few pounds up to half a million dollars, surrounded by barfen white quartz in immense quantities. In other mines we find the ore in threads and atringers, more or ieB8 parallel to the general direction of the walla, fad- ing out into the country rook which evidently forma the general mass of the vein in fact constituting ita ganKue, These and other allied facte suggest the modern explanation, which attributes the filling of veins to the circulation of heated watera in the earth's crust,

DisiribuUonof Metah, etCfin Nature. — Of late yeare researches into the constitution of Bea and min- eral waters has revealed the presence in them of a long list of elements in the form of salts, establlBhing the fact of their solubility in nature as well as in the chemist's laboratory. In mineral waters the metalairon. arsenic, lithium, CEQsium, rubidium, copper, 2inc and mauganeae have beon detected, along with the elementa of earthy minerals which form the gangue of veins such as silica;, magnesia, lime, alumina, fluorine and baryta; besides soda, patash, boron, chlorine, iodine, bromine, phosphorus and sulphur, many of which latter form aalta which are exoesBively aoluble.

Sea water, according to Prof. Forcbhammer, in addi tion to the oblorides and sulphates of sodium, mag- neeiuD], potassium and calcium, contains silica, bono acid, bromine, iodine, fluorine as aoid, and the oxides of nickel, cobalt, manganese, aluminum, Kino, silver, lead, copper, barium and strontium; and arBonic, gold, lithium, rubidium, and caesium have been dis- covered since Forcbhammer wrote The experiments

VlLLtNQ OF MINERAL VSmS,

To?

Prof. liWerBidge on tbe sea water off the coast of Australia give pasitive reauUB aa k) the pieBentie of gold. Other in vest i gators also have detected gold in aeft water,

Daintree reports the oociii'renoe of gold in the aer- pentineB aod pyritic dioritea of Queeueland, and the pyritio granites of New Houth Wales.

The ziodulos or coDcretions of EDanganeBfi dredged from the ocean lloor by the Challenger expedition showed the presence of nickel and cobalt

Prof. F. Sandbergfir has announced the diacovery of small quantities of silver, lead, copper, nickel cobalt, bismuth, arsenic, antimony and tin, in aiHoatea As olivine, augite, borneblende and mica, -whioh are ooQstitueuts of igneous tooks.

Prof- Dana recorda the occurrence of nickel in the VeBavian lavas, aud also the chlorides of lead, copper, iron and manganese, as forming on the lavas at the craters from the heated vapore; and situilar results would probably be obtained at other volcanoes had they been as carefully studied. He also notes the presence in minerals which foric a portion of gneiss and granite, of manganese, lithium, cerium, lantha" riuui, didymium, yttrium, zinc, berylium, titanium, luolybdeuum and cobalt; the latter metal also in nqica schists with arsenic.

J. S. Curtis determined the presence of gold add silver in the silicates of the rocks adjacent to theCom- stock lode, the silver chieily in those of the hanging -nail diabase or porphyry and the gold in those of the foot wall syenite; and when writing on the quicksilver deposits of the Pacific coast of tho United IStates, Prof. G. F. Bsoker reports the presence of antimony, arsenic, lead and coppeT in the underlying granites at Steamboat Springs, Nev. ; and records the fact that these springs are to-day depositing quicksilver, gold, fkntimony, arsenic, lead and copper.

Daubree gives the following list of elements, ax-

108 Prospeotinq Anb

ra MINES.

ranged somewhat in tlie degree of their impqrtaBioe (Maskelyiie adcle lithium aud aQtimany); irOD, mag* nesiuiD eilicoD, oxygeD, niukel, cobalt chrocaiuDJ, mangaueaa, titanium copper, aluminuni, potasalum, sodium, calfiium, arsBnic, phoaphorua, nitrogen, sul- phur, chlorine, carbon and hydrogenj eeveral of the corapouoda of which are peculiar to meteorites. The majority of the met-fiDroids with Tvhich the earth cornea iu contact are exceedingly ginall, and a "weight of 1,000 lb. is probably nncommon, but when the daily number encountered hy the earth, estimated at 20j000,000j is naultiplied by years and centuries it ia eTident that the addition of their contained minerats to the earth's surfaoe is worthy of notice- These miuerale, forming part af the sedimentary strata, could find their into veins without even the intervention of volcanic agenoy. It is more than probable that the cobalt-nickel-manganeBe nodules of the deep sea ara derived from the meteoilo duet falling on its surface.

Outside of the eruptiTe rocks ws find ore minerals disemiQated in secondary or stratified rocts, such as elates and sandstones, as well as in liirieetones, and it is from all of these sources combined that the metals have been ooneeotrated into veins.

Underground CirculaiioTi. — -It ia evident that water is the active factor in all tbeee changes. We must remember that a considerable portion of the water which falls upon the surfane of the earth does not pssa off promptly into the rivers, but is absorbed by th earth and rocks, and by the action of gravity pene- trates to depths practically unknowQ. Of this we have absolute demoDstration from its presence in the quartz orystala of deep-origined eruptive rocks, as numerous but exceedingly small bubbles, only visible under a powerful microscope; and from the enormous 'volumes of steam which are given off by volcanoes in eruption and which continue to be evolved from the lavas after their ejection. We must not imagine the

Filling Of .Mineral Veins.

{trust of the earth as a sulid znasB, through only the crevices of which water may find a [laasage; there is abundant GvidtiQce that every partide of the earth's crust to depths of which we have any kuowladge and presumably far below, ie oLiyged with water, and tliat thete is no subBtauce known which is not permeable by ii* Under pressure it oan be forced through iron, appearing aa a perBpiruttoti on the outer surfaoe of the Gonliuiug flask, and with auch a practical demon- Btration we are compelled to admit the fact as stated.

Beat — While thia water at the surface may be cold, we know from the evidence of borhiga and mining works that the temperature iocreaees with depth from that point near the surface at which it remiJiins sta- tionary through aumruer and winter alike so that in the Gomstook lode, at the 2,300-fL level of the C, &C, shaft, the thermometer Teg:istered| about 150' Y., and at the 3,000-ft. level of the lellow Jacket shaft 170°. There is no difficulty in iiuflginimi this temperature iuereasing to the balling poiut of wuter (212°') and risiug greatly hisbor, until it beoomas bo intense the water may he said to be "white hot." This heiit ia not the product of actual firea. It juay be paitly caused by chemical action, but is more exteuaively due, iu all prob:ibility, to the pressure on the earth's cruet caused by its eteady aud coni*tn.nt noutractiau as It QOolst and to the friction from the wrinkling move- anents. The rocks become hot during compretieiuu and movement and impart their heat to the coutahied "Watar, which, aided by hydroafcatic pressure, bringa it to the surface and it is dissipated in hot springs; or, if euch a vent is not made, by volcanic eruptione, or the iutruaioD of lava into upper aud colder strata.

Solutiotit TranajXiHation and Deposition. — We are 31.01T prepared to understand the action of water in the Bubaequeut procesges. We Lave the waters penetrat- ing tho rocks everywhere, the cooler waters descend- iDg, the heated ones tending to riue or being forced

no

And Valuing Muses.

to tba BurfncQ along the linea. of leaat reBistatice, &tic}i aa the ffkult tiaaureB by tlie pressure of other tvaterB or steam.

The ability of water to decompose rocks depends on the presence of carbonio acid and alkaline material such as the carboaatea of soda and potash and its solvent powers are inoreasfid with a rise of tempera- ture. Its fii-sfc carbonio acid is derived by rain water from the atmoapbere. and the moment it touches the earth it begins work of decompoaitiou and rear- rangemeut, picking up and dissolving one mineral and depositing another. Water traversing an open fissure would thus leave a portion of itg contents on the walls, both sides alike as it giradually cooled in its ascent, just ae sugar candy will crystallize out of the sugar solution aa it ia cooled or evaporated, the process of cooling: producing the same result as that of evapora* tioDj in both caeeB the liquid being unable to caiTy ao great a lod drops it at the tirafe opportunity. In thie manner bavs veins like those of the TVheal Mary Ann lode in Cornwall been formed (pi- 1, fig, 4), e, being chalcedony (silica combined with water), &, glassy quartz terminating in crystals; c, galena; and the oentral core d, ohalytite (carbonate of iron), the depo- sition on both walla being similar and indicating the origin of the minerals. The change in the deposited luiueral may have taken place either because of the eiibaustion of the locality from wLioh it had been col- leflted by the water, or from such divergence in the coarse of the underground flow by disturbances like earthQLiakea that the material was drawn from a new series of rocks. A similar incrustatiou of small ostI- ties by waters abounding in ailiaa has formed agates, the banding being due to the changing presence of the coloring material. Compact and close-grained as these agates may fifiam, they are in reality porous, for it has for centuries been a common practice to boil them in suitable materials to iiutrtia.sQ the brilliancy of

iifQ OS' MmEUAL vsim

the coloringof the batidfi, the chftuge being diis to partial abaorptioQ of the material %\'ith which they have been treated. When the cavity haa not been completeJy filled, it is either left with a amooth sur- face of chalcedony (which does not crystallize) or lined with cry&tAls of quartz, calcite, eto. In auch manner ako have opals aud other minerals been intro- duced ixito the oval cuvitieB of baaaUic lavae, and tLua we haT© also an explanation of how minerala can deposited as crystals on the top of ench other by juRt Buoh changes in the character of the circulating waters. Source of the Ore. — The source of tho juiuei'als turns deposited is to be found in the country rocks of the legion, mainly tlie eruptivea, which, aa we have Keen, contain nearly all, and probably would he shown to contain quite all, of those known; or even from the eeeoudary or stratified I'oekg derived from older jgueoua I'ocke, into which the mineral oonatituents of the latter must uuqueetionably have been carried dur- ing their deposition aa sediment. That lavas baTe been deprived of their valuable mineral oonetituents iu this way ijs fairly proved by the experiments of Prof, Backer and Dr. Cavl Barua, on the Comstock. The hanging wall of that lode is diabase (in Virginia City), known by the iniuera aa "blue porphyry," a term which well expresses its appearance when freshly broken. The Sutro tunnel has espoaed the structure of the east country (that is, on the hanging wall aide) for more thau three milea, and developed a series of bands ehowiii* pJaiuly the retiulta of solfataric action (by heated waters), with alternating bauds of hard blue porphyry. Outside of, and nest to tha lode, the rock is hard and auggestive of no cbunje, except by the presence of iron pyrites, which is neai'ly always a product of decomposition, but under the microscope it becomes evident that extensive chauEes have taken pUce hi. it, Its crystalline strut;turs haa been modi- £edj the hornblende and ugite (gilicatea) have been

h

Prospsctwo And Valuing Mines.

altered pyrite havitig beea made out of their iron, anil the Bil\er which ia present in them further avf&y from the lode has diBappeared, the natural couclusion being that it has found its way into the lode through water.

Form of Deposit, — AU veins were not formed ia the manner described! as occurring at the Wheal Mary Ann lode and others similarly oonatituted. This presup- poses an open fisHure, and it does not eeem possible that all fissures in which veins havs been formed re- mained open during the procesB. lu many it is plain thfit such v/aB nob the case, because they show uo true walls, as in the Great Plat lode, Cornwall (pi. 7, fig. 6j and ph fig. 3), where the ore B is frozen to tha dike A, and there is only one wall ; or in pi. 6, fig* 1, whore the mnsaes are lenticular and not counected with each other (Keystone mine, Cal.); or in pi. 6j fig:. 2, ivhere there is no trace of banding, and the hanging wall shows many feeders or stringers not seen on the foot wnW, The wainteiiance of an open saure in the case of such a structure, as pi. 2, fig. 2 (a generalized cross laectiou of the Comstock lode in Vir* giuia City), would have been an impossibility for the three or fuur miles of its length, the foot wall having a dip of only ; but it ia equally plain that a elijht sliding of the hanging wall on the foot would produce just euch cracks aa a, fe, c, rf, accompanied by an im- mense amount of broken material. In many such cases there is no true gangue, the ore occurriiii? in the orig- inal country rook decomposed it is true, in hands or Btringers more or less parallel to the walls, or strike of the rocks which have undergaae decomposition, but fading out into the unaltered country rook on either side as at the Great Flat lode, or only on one side, as in pi. 6, fig. 3 ; while m fig. 1 there is one true wall at the contact line. In tbeae cases we can only account for the presence of ore on the supposition that as the percolating water dissolved and carried away the par-

M

FILLING OF MINERAL VEIIfS.

tiolea of the rock it left in their place partioles of ore* simply making an oixchange, and. it can easily be undeTBtood bow ihia substitution would go on moat rapidly and moat extensively ia those portions of the lleBiirewhicb had been moat shattered during Us forma- bioD, as the material ould have been more largely ground into powder at such poiEts, not only allowing more "water to find ita way throuy;h those partions, but preseatiDg vestly greater surfaces to the action of the water. 'Thus a cube with faces 1 in. square has a suffac© as 6 to 1 of bulk, whilii a cube with faces 2 in. square has a surface of only 3 to 1 compared with bulk. It ia at such places that tbe largest deposits have taken p[ao@, atid it is thud that "hordes'' have usually been formed ia tbe lodes; not by masses falling into an open fissure, but by the water circulating through crevices, completely surrounding a block of country rock. Wc ooiistaiatly find pieces, of country rook in veins completely incloaed in ore, and these are only horses on a ?ery small scale. The Savage mine, at Yirginia City, afforded abundant spectmena of min- eralized porphyry, suggeatiug this origin, and thoaa of Monte Cristo, Wash., offer many mors illustrationa %¥hieh are totally inexplicable on any theory of large open fissures. Many such veins have acquired slicken sides andgougeby sub&6<iueatmeveraent3 of the rocks, which would naturally fallow such lines of weakness, and may even have undergone a partial rehlUng and reconcentration of their own constituents, some por- tions having been impoverished to enrich others. That auch movements have taken place is shown by th crushing of the quartz in some of the larger bodies on the Comstock lode so that it was known to the miners as "sugar quartz.'

These examples suggest an explanation which will account for nearly all cases of vein Btruoture, and at*' tentiou in the field will nbow how beautifully the cyole of changes is constantily in progress, beginning

114 Puospecting Asd Valuing Mines.

with the earliest fraetuhag of the roots aod the first rainfall, with uo oeesation to the fireseiit iime.

nationality of Natural Frocesses. — A moment's thought will ahoiv thut under any cir<:umatant;ea some Buch reiiilta as have IjGeD outlined munt havo beon tha outtiomo oi tlie surface changes of the earth- Even had the oritinal veins been solid masBee of gold, silver, copper, etc., their contents would, as they were worn away, hava been scattered ffir and wide through the rocks which were formed out of the earth's first cruat, even if that cruet itself did not contain them, and the condition of the rocks which we have pictured would have been one of the first results of eroaiou, and the formation of veins by segregation or substitu- tion must have commenced even in those early days, by the workings of the laws of chemical affinity-* which imply the abandonment by one element of its associate in a GOmpound whea it meets with another which is mora to its liking under suitable conditions for mak- ing the exchange.

How easily these changes are effected may be seen in the ocoasional action of metallic compounds in the cabinet. Just as the iron pyrite crystals, so abun- dant in some of the gravel mines of California (pi. 11, flg. d, shows a petrified tree covered with them) drop to pieces and decay with extraordinary rapidity so specimana of pyrite of the bronze-oolored variety from the Glacier mine, Monte Criaho district, "Wash., after remaining in the writer's cabinet only two months, were entirely decomposed, the pyrites having absorbed tnoi&ture which Gombining with the contained sul- phur had produced aulphurio acid, which in its turn had combined with the gnngue of the specimen (par- tially altered porphyry), forming gliateuing salts and rough concretions, not only on the specimen originally attacked but on the adjacent ones which happeued to be in contact with it, however slightly. The amount of moisture absorbed was so great that what remained

cif the specimeDB oould not be bandied without Atam- ing the haade black. On seeing thti chaage the writer Temembered extraotiug: from the same vein, in a prev- ious year, gamples with the eame appemrance, baling; undergone the same changes in place. If then the &mall amount of moisture which is preeent in a dwell- ing room can effect such chflDt:;es, we are at no lose to uQderatand how much greater cues can be efEected by nature in her vast undyrground workshops, with her bbeolute disregard of the eiemeut of time.

Ore Dfpodta in Limestone. — In a somewhat similar way have the greater parfcion of the deposits in lime- atone been formed percolating Tvaters eating out pas- saea and chambers, which have been eubaequently fiiled with iron, lead or zinc ores by the waters trav- BTaing them. The ability of water to excavate caves, anoU as the Mammoth Cave in Kectuckyi and hundreds of othera in all exteuaive limegtone regions, is so well tnowii as to require no further comment, except that tbe taost remnrkable feature about them is their sub- setiuent filling with large bodies of mineral, usually of only one or two kinds, much Igsb complex in their coiiBtitution than the filling of reins; which suggests a different, probuhly cooler, condition of the percolat- ing irater. Such deposits are of the most iiregular Shape, due to the vagaries of the water which hol- lowed out the chambers, and when the walls are lynched tliey may generally be scraped clean, as the iniueral does not usually penetrate the limestone to *ny depth. PI. 6, fig. 8, is a sketch of such a deposit formed in limestone, on the bedding planes and joints controlled only by the lines of How of the water itidiofited by the arrowheads. Such are the depoaite o( "WJBconain and Ulinois. Fig- 4, same plate shows limestone traversed by the dike B, and the arrow- lieadB the possible direction of the water flow, which if descending, as at might form ore bodies as shown iii black, or if ascending, as at C, either aa hot or cold

116 Peospectiug And Valuing Minb8.

water under presBure would present similaT Btmctnre, Fig. 7 shows the Btrttcture of the teiDs at Tombstoiie, Ariz., being Rxncesaive strata of slates 5, HmestoDG, quartzite Q, and dolomite (magnesiBn limestoce) traversftd by the quaitzose fissure veins A,IJ which ai'e noiinected in the limeetone by the flat bodies of riah lead ore, C In \A. 1, fig. % we have at LeadvjUe, Colo. J leadoreslyiBg between the limestone flour, the deposits being nearly horizontal, and porphyries for a roof.

On pi. 7, fig. 2, we haTe hematite deposited in cavities of the moHntain limcEtone A, at UlverstoEe, Kngland. Subsequent to the deposition, of the ore it is evident that a further portion of the limestojie was disaolved by waters free from ifon, forming a later cave which was filled ivith the clay G, the whole being probably rartiolly worn away before the coTeriug of dirt D was laid down at a much later date. In fig. 3, same p]ftte, we have a similar formation at Altenberg, Germany, only calamine (silicate of zinc) takes the place oi the hematite in the former illustration. is a body of limestone, lyins between the Biatea the zinc ore D filling a cavity of erosion, and the clay C filling a cavern of later date formed after the deposi- tion of zinc ore hod cGnsed.

In moBt Ruoh casfS it ia probable that the filling toot place by waters percolating through rocks of later formation, lying above the limestone in "which the oaverns were farmed, from which they abstracted the iron and zinc, only to redeposit them \vhen presented with a more tempting morsel in the shape of lime.

Ore Po!fi<i}ihj Derived Direetly from the Sea. — Most chloride and bromide ores of silver and kail are found near the surfaoe, in the joints of liiueBtoDes and quartaite; it is very probable that such rocks hare derived the ore found in tbem from sea water when they were a portion of the ocean bottom. In Arizona there are many occurrences of these ores in localities

Tme Filling Of Mineral Veins.

where suoli a oonditioii Las been possible, there being; evidences of the former existence; of on ancient inland sea. A Biiailar explauatlou ia advanced to account for some gold-bearing conglomerates, in whioh the goldia Buppoed to have been precipitated from the ooean near shore. By a eecondury process the gold sparsely disseminated in mud beds at the bottom of the sea might be concentrated in g.uaitiz veins, traversing the shales and alatea formed by the oonsolidation of these bedB. The ocean-formed axe bodies would, if derived directly, be beds or impregntttiona and not true veins.

Electro-chemical Action, — Around many of these phenomena, as around so many of the operations of nature, there hangs a suspioion of the intervention of electrieity. The aetion of electrioat currents ia forci- bly suggested in the case of native copper mixed with native silver, or of gold crystals deposited upon horn silver; but even if such an agency was active in their production there must have been a previous leaching of other rocks to provide the solntioDS from which the metula were reduced and crystallized.

A Cycle of Perpetual Change. — That operations such as we have been describing are constantly going on in ttature, and that no estraordinary processes need be invoked to aecount for the phenomena we Bee, is plainly evident from the changes which take place in the outcrops of veins and elseTvhore. Wo constantly find incrustations of various salts, sush as alum and those of Boda and potaah, forming on tha sides of caves, and even of other minerals on the walls of deserted mines; we secure copper from the waters discharged by copper mines or mines of coppery iron pyrite by allowing it to run over scrap iron, which is destroyed by the acid in the water and copper released; the pyrite in the outcrop of veins is decomposed under the joint action of air and water, leaving a deposit of rusty iron- stained gaugusj while the sulphurio acid percolates downward to produce other uhangea; we find surface

118 'PuOSP&OTINa ' J

m MIMES.

pyrites likewise decomiioaing, parting with their sul- phur and iron, ouly to combine with oxygen, and form tha red and black oxides of copper, whiGh are richer than the original ore, and in. fact &re merely ooncen- tratea of oree whieh may even be too poor to work vhen the limits of the changea are reached, which is usually where the preaence of permanent water pre- vents Goata{jt with the air. Ye also find that many carbonates of lead have a core of galena, which is the sulphide, and know that the con-version has taken place since the deposition of the galena; and if we look carefully around U9 wevill meet everywhere with alterations going constantly forward. Brought up from the unknown interior of the earth by lavas, the minerala are collected from them into veins, only to be again scattered as the veins are worn away in the general deatruetion of tho earth's surface, and mingled with the fragments of the lavaa in sedimentary de- posits, which, as we have seen, ultimately return to granite, only to be intruded into the overlying strata, the wearing away of which uncovers the granite, and the circle ia completed. Formation, rearrangement, destruction, reformation and return to the original are the perpetual cycle of the changes in veins, and not only of them but of the rocks in which they are con tained.

Local Limitations. — These views afford a natural explanation of the reason why mineral veins are con- tined to certain regions and are not found in all areas of dialocntiou. "We have no knowledge of the appear- ance of the original crust of the earth, as it was formed under conditions which we can uever hope to see, but it is evident that all minerals, except meteor- ites, now upon the surface of the globe, in whatever condition, muat have been derived either from iter from rooks which have been ejected through it. At the moment these began to decay we have the oom- mencement of the whole stratitied series through

The Filling Of Mineral 7 Sins.

irbicb is some form or otlier, all the mineral coDatii- uenta of the origiDol rock must be scattered, accord- ing to the size of tlie particles, except those which Tvere perfectly soluble; but always on lines deaoend- lug seawards. In the course of time these sediments t01lld be agftin brought to the surface, to be again Nvorn away into new sedimente, mised with the debris of a new series of eruptive rocks, the process being repeated with eyer-increasing complexity, but with a constant iucreaBe in the metallic contents of the crust, if auch were brought from below by the eruptive rooks from time to time.

But just as soon as fracturing begao and with it the circulation of heated waters, the concetttrfttion of the minute particles; into veins would beglu which as they in turn were eroded would furnish pnrtieles of larger size to the sediments, and in time these might ccmtain eufficienfc minerftl to form l&rg© deposits when concentrated by the circulating waters, even at long distances from the seat of the original eruptive rooks from which the mineral was derived. Such sediments, still retaiuiug the mineral fragments, like the lead and copper-bearing shales acd saudstones, con be goU'- ceived to be still forming.

We can now see why all fractured regions are not metalliferous. There must have been an original area of eruptive or volcanic rocks to start the metal-bearing series, for without this no amount of folding or dislo oatioD could have produced an ore Tein,

We can also understand the spotted or pockety charter of many veins; and why there should bo often be in a district oue strong "mother" vein, as the dkiin fisenre would offer more unimpeded channels for the circulation of water than the smaller lateral GrevicBs; and why veins of different geologic age in the 'same district should be filled with different min- erals, as the source from which the first series was filled mayhnve been exhausted befora the formation of the next.

CHAPTER Vn.

INFLXJENCE OF ROCKS ON VErN FILLING.

It Ib e'vidtiDt that if there is any relationebip be- tween ore minerals and rocks, or if, in other wordB, the useful minerals are more particularly found aaaa- ciated with some particular rock in preference to others, tb© knowledge of the facta would be of great v&ltie to tbe prospector, for when he had gained an idea of the rocks of any particular district he would have a general idea of the minerals which he was likely to find there, and could familiarize himself with their appearance, from hooka or otberwiBe and not only know what to look for, but bow aod to recog- nize them when found.

The following imperfect table, compiled from reoog- mzed authorities, while far from being aa complete aa could be wished for, undeniably shows that there ia puch an association of minerals with certain rocks, the reasons for which we may not at present thoroughly understand, but which i& not only of interest but of practical importance.

The greatsat difficulty in preparing such a list is to give equal prominence to all parte of the subject be- cause while a certain ore may be found at two separate loGalities ia two diflerent rocks, it may be of no eepecial value in one of them and ol Tast importance in the other. It is almost impossible to correlate Buch differenceH. One might quote 20 minea in a single district, all having practically the same character, and only one in another district of different rock

Influence Op Books On Vein Filling. 121

Btruoture but produoing the same metal thus giving undue prominence to the former mode of occurrence ; and it is not alwayB possible to estimate the "personal equation" in the variouB published accounts, which phrase is understood to include the amount of knowl- edge and accuracy of the writer and preconceived theories unconsciously coloring his views.

To overcome these difficulties, and yet keep the table within reasonable limits, a limited selection of oases where the information was full enough has been made from the literature of the subject. The selec- tions are for districts, not individual mines, and though insufficient for a thorough scientific discussion, will be sufficient for our purpose. It does not include iron ore, as that is chiefly found in bedded deposits, not subject to the same influences; nor the minor minerals, suoh as nickel, cobalt, antimony, bismuth, etc., as they are usually the accompaniments of other ores, and do not form the prominent or controlling mineral of the deposit which imparts to it its positive ohar- aoter, although these may have a preference for one mineral rather than another, and occur most frequently in combination with it.

Influence Of Rocks On Vsin Filling, 131

The rocka in the foregoing tables may be further claasiBed aocordiug to the amount of silica or quartz which they contaiiij into three groups :

1. Highly slUcious: Granite, Kneias, mica Bchiets, sandstonee, coBglomerates quartzltea, eruptive rocks, and some limestoDes.

2. Moderately silidous: Chlorite, talc! and clay schiata and shales, Qonglomeratea m part, and some lime- sfcoQea.

3. Scarcely silicious: Limestones and dolomitea. amining the metals in the foregoing list 'we find

in the cane ol —

Gold. — Twenty-six occuiTeneee in rocks abounding Id quartz (ailicii) out of the 34 localities, and id some of the remainder the game coi]ditioQ& probably tiziat, AS many shales and conglomerates are highly dlicious. Only one oocurreuce is noted with limestone and in this case the foot dll of the deposit is granite.

Gold aitd Silver. — Ail three oocurrences are in rocka abounding in gilica.

Silver (aBide from silver-lead ores 'which are clasaed as lead) occurs in 13 very quai'tos© rocke out of 13 instances, and the renjaining G are probably silicious, fig many limestones are highly ailicious.

Copper also oncura with 18 very quartzose rocks, and X'robably with 19 out of the 21 localities, if not more, as the Clifton deposits are differently deaci'ibed by two writers, and the other limestone locality may carry much quarts.

Lettdi however, occurs in the quartzoee seriee in only 10 ont of 25 locaiitiea, the remaining Id being in nasociation with limeatoneB, while some of the former may have lime to some extent as a minor eonstit- uent.

Zinc shows 6 out of 8 times as an associate of lime- Btone and only twice in the quarUose group.

Ti?i. — All 8 of the occurrencea are in quortzosa rooka.

132 FROSPmriNG AND VALUING MlUfSS.

Chrome. — All 7 localitiea are in serpeDtiaes, usuAlIy associated with gueiBsic or Lornblendic rocis.

Monganfise ie aseociated witL both estreiues of rock,

Meyvurij. — All 10 localities are in highly metamor- phos€d rockB of various kiQcIs, hut uearly all are aeso* ciated with recent eruptive rocta and hot gprirgs.

The relative imporhmce of tbcse occurrences ia beat tested by tbe output coiaiuercially of the different iiietiils. Tented iu tbie way the highly siliciouB Toeka produce the bulk of tho gold, eilver, copper and tin; the non-BiliLdouB or true limestone rocks, the bulk of the lead and zinc, and rocks 'which on decom- poeitioQ yi&ld both silica and lime, giTe complex orea of gold, silver, lead, copper zino, tin and manganese with taany other less prominent metala.

Mftah Assoditied With Each Other. — Gold and silver are eo intimately associated in nature that all gold may be Baid to contain some eilver; and most silver orea carry gold, from mere traces up to impor- tant values. Gold containing a large proportion of silver is pale in color and is soBaetimes called "elec- trum ;" wbila eome native gold-ailver alloys are almoBt white.

Lead and silver are also so related that lead ores as a rule caiTy eome silver, if only a trace, and froEa that up to large amounts in value, though not in bulk, without any special change in their outward appear- ance- Lead and zinc are also intimate associatea, aa are also lead and antimony.

Copper and silver, or copper, silver and gold, often go together.

Iron and manganese, or iron and chrome are fre- quently aasociated.

Nickel and cobalt are closely related, both ohemi- cally and in ocourrence,

Arssnidea and anttmonides of other metals are often found together and either or both with aul- phides.

mWL UENGE OF ROCKS ON VEIN FILLING. 133

Coixntry Rock and Gangue, — -The ore minerals proper usually compOBO only a frnction of the wbuls -vein filing, tho gauue mineruls being present m larger, often very much larger quatitiiy. The rocks through which the underground waters pass luuat qod- tain material euHable to form this gangue — silica for the quartz, lime for the calcite, tluoriue for Huorepar, sulphur for the Bulphute minerals, etc. The gangue mineralB are ulusely relateJ to the metals and truo ore minerals (as quartz to gold oalcits to galena, etc.); hence the connection ia really threefol<l — country rook, gangue ore.

Helalioji of Eruptives. — -While eruptive roclsB are frequent accompauiineutB of ore, they are not aheo- lutely essential to ita presence either in thesilicioua rocks of Otago, Nen Zealand ; or the sandstone reefs of Bendlgo, Auatraliaj, or the non-ailicious limeetoneB of the Central States in America, In only 60 out of 137 caaea are eruptive rocks mentioned in connection with the ore deposits as being of possibly prior origin, or about 3(15", while in 68 cases, or about 50%, there is no apparent connection of either eruptive rocks or granite. Possibly eruptiTes existing in the neighbor- hood of ore deposits, but not actually contiguouBj are somotimea overlooked or not reported.

There are cases in which the metal in the depoaite undoubtedly appears to have been derived from them. But outside of these instances there are others "where the outbursts of eruptive rocks have simply produced the necessary uonditions of heat and fractured rocks, f urniBhin waters of the requiaJte tejuperature and pro- Tiding ample facilities for their percolation through materials so crushed as to be easily soluble.

Similar results have been obtained in other places, without the aid of eruptive rocks, by the enormous prPBsure involved in the complicated folding which aee iu such casee as the sandstone reef at Bendigo, Austialia, or the abruptly folded strata in Kova Sootiaf

334 PmSPECTING AND VALUING MIJfBB.

eo that it ould appear auy cause which will pro- duce heated water and fractured rooks is sulfficicDt to furnish the condition b for vein filling, the material for forming the deposit being drawn from any one or all of the rocks indiscriminately through which the water has been circulating, -whether aboi?e, below, or along- side, near to or at couaiderable distances from the point of final deposit; and that this place of final deposit is krgely determined by the character of the rock through which the water may be circulating at the time it is compelled to part with some portion of its mineral burden, and not by the character of the cauae which produced fche fissuree or the nature of the associated eruptive rock, unless the ore is deposited in tht.t rook itself. The following e:£tract;s strike the keynote and indicate a line of ciamination which will explain nearly all, if not quite all, the phenomena of the aasooifttion of minerals with each other, and the rocka in which they occur. Speaking of the ore de- posits in the Potsdam series of rocks in South Dakota, Dr. F. B. Garpewter says: "Tbeee ores are in some sections almost exclusively gold-bearing; in others, they carry partly gold and partly silver, and again in other places the silver predominates." seems as thoTigh the porphyry at Bald mountain brought mainly old; at Ruby baain, only a few miles distant, gold and silver in nearly equal quantities (in value]; while at Galena, 12 miles distant, silver-lead predomi- nated. That is, broadly speaking, gold predominates in the quartzites, but gives place to silver as we ap- proach the more caicai'eous portions forming the upper parts of the Fotsdnm ; while in the massive limestones such ore bodies as are found, Jike the Iron Hill, carry fiioluaively lead and silver, yet the porphyry is in all inatanaes the same."

yariations in ike Mineral Solviions. — But in foUowiDg up thia line of argument we must remember that all waters will not be charged with the same mineral.

or the same wnter always ipitli tUe same mineral, as their oontenlia must vary ivith the nature of the rocka from which they draw their aupply, and consequently they can only deposit what they hae in Bohition for the time baing aDd may carry that for long distances for want of a Buitable precipitrttsng agent. They may have only one or many minerals in solution, hut at any rate "we are prepared to uoderstacd the occurrence of gold in the joints of porpiiyry, of silver in the joiute of quartzite, of lead and silver in the seams of lime- stone, and why the character of the orti shonld change ao BUiJdenly when a vein paases from one series of rocka to another, os for iuBtance from a eilver-bearinf galeba with zincblende and iron pyrite in decaying porphyries with lime feldajmrB, or a gold-bearing arsenical pyrite in the underlying granite; from copper in silicious elates to tin in a Htill more silicious grsDJte, where also the charaoter of the mica {white mica being common in tin-bearing rockg) appears to have an influence, or to be, like tin, a result of the same influence; or from ileposits of galena in limestone to barren material in the intercalated beds of "toad-

I stone" {an ancient eruptive rocli), as in the lead depoaite of Derbyshire, England. hijluence of the C'omUrj/ Hods. — The practical mioer, however, is not so much interested in the seientific explanation of such endden chaugea, but he Ib very materially iuterested in the fact that they do occur, as they may involve eerie ua and costly ohantea . ia the character of the reduction plant, or a loss of the vein altogether, aa at the Stonewall Jackson mine, Arizona, where the native ailvur found in the surface W porphyry disappeared altogether when the underlying granite was reached; orj, as on the Comstoch lode, when the fissure left the syenite-porphyry oontaot and paaaed into the underlying syenite, where it presented only oQcaaional bunches of gold ore, instead, of the silver deposits of the eruptive contact levels.

Prospecting And Valuing Miner.

Th© lesson inculoftted ie the deairabijity, to s&y the Jeaat, of a thorough examination of the line of outcrop of the ulepOBit uuder tionsideratfou, before erecting reduction works, not only to avoid the neceaaity of obange, but to determine the probuble extent of the ore-bearing ground ; for if the ore be confined to a cer- tain class of rocka in any particuJar district, the extent to which such rocks are developed ia em impor- tant element in the f ature of a mining camp, mid must largely govera the amount of tuoney which it will be wise to inrest in means of transportation eto.

The viewfi here set forth also explain why long belta of country produce similar ores, while parallel belta at no great diatauce — often only a few miles — may pro* duce a totally different seriea over a like extent of country ; or why the ores on one aide of a nountain range should present a totally different appearance from those on the other, where both aeries hare been subjected to the action of the same eruptive rocka, or to no suofa action ou either aide. Itia simply because they occur in parallel belta of rock of di£fering com- poaition, the outcrops of which are presented to us on the flanka of the mountain rangea in which they lie, more or less paraUel to the general summit of the range or Bxi of elevation. Thus below the free gold belt of the mother lode in California — which, however, ia not a lode in the true sense of the Avord, but a beU of gold-bearing rock6 in which many deposits ocour roughly parallel to the general strike — there lies in the foot hills a band of copper-bearing rocks of equ al estemt north and south, while higher up in the range there is a belt of limestone country with which are aasociated orea of a more complex character, galena as might have been expected making its appearance.

Again, just as the ancient schists of the Carolinas and Georgia furnish ores of the same character, over a distance of many miles, so do the ancient metamor- phoaed rocks of the Cascade range, in Washington, fur-

Influence Of Roves On Vein Filling. 137

Dish for miles on the 'western slope complex ores of very UDiform character iu oacli member of the rook Reries, but differing entirely from those on the eastern HAnk of the eanie range.

It is for such reaaODB as these that geological surveys may be of very great utility, if they can be maile be- fore the dJBtricte have been eshausted and all the thonsand and one experiments and failures have been tried and Tnade; but of no direct and local value what- ever if undertaken when the mitiiQg camp is wellnigh deaertfid, although perhaps useful in showing a com* pariaon with other locolitiea.

OHAPTEE Vm. BIIKBRAL DEPOSITS OTHER THAI VEINS.

Succession of Formations. — Aa we havo seen in dis- oua&ing tbe filling of veins, it vias not neaesBory in their case that the liliiug should have been derived from rocks Tvhich lay at a greater altitude than the deposits ivbich Trere beiog formed, although without doubt 8 larie portion of them may liave been so situ- ated, but in the formatiou of bedded deposits in atrat- ified rocka only a very iuaignifieent portion are derired from springs, thermal or otherwise. Depoeita are laid down on the top of rocks fUready formed and covered up by others of a later date. WhiJe these latter must of necessity lie conformably on the deposit, or cover it horizontally, those on which the deposit lies were uot neueesarily qo. A mineral formation may follow in orderly succession as one of numerous layers, or it may be laid down on the upturned edgea of older strata, which have been tilted up aud largely worn away before they sank again beneath the water and received a new coYering. In pi. 2y fig. tbe strntB E, Gf i>, lie conformably on each other, but un- oonformabSy on the tilteJ series A. If there be also suoh a series as // we infer that it was laid down on A; that a gradual horizontal upraise brought B out of the water and permitted tbe destruction of most of tbe series; and that a subsequent depression, vithout tilt- ing, allowed tbe deposition of E, C, D, which are also said to bo unconformable to B; but it is evident that it will be much more difSoult to trace the true reia-

Mweeal Bepostts Other Tban Vetnb. 139

tionship "between E,CtD and B than between -Band

The jiioat iiijportaut deposits to uis, outside of clays and those wbiGli have, formed building stones, mb those>of coal and iron ore; salt, gypsum, carbonate of Bodn, niter, and tbe allied mineraJe. The action of water ie evident in tbe formation of all these, ae the agent by which the material bftB been collected, except in tbe case of coal whether thej' have been ruade by tbe ocean, to which tba contained mineralB have been carried by atreams frouj higher altitudes, or in inland basins long since dried up, to the lower portions of wbicb other rivers have carried in solution the mate- rials derived from the ridg:es bounding tbe basin, and which are now in prooeee of decay,

Solrent Capacity of Water, m\d Evaporation.— We have seOQ previously that heated waters have tbe power of holding in solution a lar;er quantity of any given material than those of lower temperatures, and that in cooling they ars compelled to deposit a portion of their loadj as in tbe esse of hot aprinia, which build up masses of sinter around their oriticea. Tbe quantity of mineral matter which such springs may bring to tbd surface will be better understood by tbe Htatement of Prof. Ramaay that tbe hot springs at Bath, England, discharge annually sufBcient solid matter to male a column 140 ft. high by 9 ft. in diameter. But whether hot or cold there is in any cate a point at which waters have abBorbed and bold in suspensioD tbe juasimuin Quantity possible. This in called the auturatiou point, and such a solution is aaid to be saturated. If more solid matter is addecl to such a solution it falls to the bottom UTidieaolvod, or if tbe amount of water be re- duced by evaporation the same result follows; a por- tion of the diaaolved matter is squeezed out of the Bolution as ita particles contract on each other, and falls to tbe bottom. Tbe iocrustation on boilers is the result of juat such a process, and the principle ia

nOatBCTlNG AND VALUING MlN£!S.

applied artificially in the produotioDof salt from brii Id nature we see it in the drying of the jvound after rain by the wiuds and auuahinej th grouud loBiug; aud the air ab.sorbin the moisture; but few personft realize that the losa froia large reserioirs is equal toi 3G ID. annually over the entire surface; and ie stil greater in shalloiv 'vfa.ters, There in excessively hov aud dry climates, the io&& by evaporation may rise toj ae much aa I in. in 24 houre, atill going on even dur'*' in the night. So great indeed ia this evaporation in! the deserts of the Great American basin that all tbei; rainfall ia taken up in this manner, the numerous lakes having no outlet, but varying in size fram noBth' to month, and day to day, ae the raiufall or aunabina gains the mastery, shrinking in hot and day and ex-' panding in cool or wet weather, and always maintain-i ing an area which is just large enough to enable thai evaporating agencies to take up the exact aniiount of "water ilowing into the lakes. The popular notion of subterranean outlets for this water has no foundatioi in fact, as evaporation is BuflSdent to account for all! the phenomena- 1

But in this process it is only the water which is lost;! whatever minerals or eolid matter it brought downi from the mountains into the lakes ia left there, accu-' mulatiug slowly but surely, no matter how Bmall tha) amount may be per gallon of water, until sooner or' later the situration point is reached, and a deposib, begins to form of 'whatever salt may be least easily held in solution if there be more than one. For %. time the annual influx of water may be able to redis- uolve the precipitated portion, during the more rainy' part of the year, but in the course of time this precipi*; tate will exceed in quantity the amount soluble in th' annual inflowing water and a permanejit depoflit will| begin, the surface of which will suffer a partial re: solution annually, but the tuass itself steadily increas-' ing in bulk. In this manner have gypsum, rock salt

Minebal Deposits Other Than Veisb. Hi

and carbouBte of soda bsen deposits d from saLine waters gypaum from Bea water saturated with the sulphate of Uiae, but able to bold a,ll its chloride of Bodium (conamon salt) in golution ; salt fiom siiuilar waters by evaporatiuQ, the in eucb cases contain- iDg the small aiuc>unts of Bulphate of lime and othur miDerals which may be in jolutioa aT]d whiub consti- tute i tg imp urities. Both of these bu bsfcances aro therefore purely mechftnifial prfcipitatee. Natural evaporstioD has in this way produced enormous masses of rok alt, like those of Cheshire, England, and Cracow in Poland, both of which are esteneively opened by underground works; or that at Sperenberg, near Berlin, which has been penetrated by an artesian boring to a depth of 3,307 ft. without the bottom hav- ing been discovered ; or thoae which are exposed on the Burface on the Kio Virgen (or Virgin Kiver) in Nevada, which are described as follows: *'A fonuation exists at this point composed of rock salt resting on, and to some extent intermixed with, eedimeutary xocka, and of such magnitude that it may be said to constitute a notable portion of the hill in which it occurs. More than G0% of this entire maps appeal's to consist of hard rock salt, havinti: the truaapftifncy of clear ice, and containing over 90% sodium chloride. This formation extends along the eastern bank of tho Tirgeit, irBsenting a bluff face to the stream fur a dis tance of 25 miles or more, and reaching in BOino places a height of seTeral hundred feet."

These deposits are so enormous that we might even be disposed to question the power of so simplo a cause to accomplish the results which are still, however, being reached at Carmen island in the Gulf of Cali- fornia and elsewhere, but the following deBcriptiiiu of the Katahoghaz sea (from Sir A. Geikie) will show them to be not only probable but poasible: ''Along the shallow pools which border this sea (the Caspian) a conatant deposition of salt Is taking plaoe forming

gometitJies a pan op layer of rose-colored cryetnls on the bottom, or gradually yettini; tJrj anil covered witli drift sand. This couoentration of tbe water is still mure marked in the great u0!jl]oot called tbe Kara- bogbaz, ia conneeted with tlie luiddlo basiu by a channel 150 yds. wide and 5 ft. deep. Through ttis narrow mouth tbfre flaws from tbe main soa a oonstant current, wbioh Von Eaer estimated to carry daily into tbe Karabogbas 350,000 tons of salt."

Tbis amount if all deposited would cover 250 anrea to a. depth of 1 ft.

Suiib deposits belong not only to tbe open sea, but mostly to inland seas or lakes wbich bave originally formed a portion of it, and coQaegtuently partook of the general diffuaiou of tbe salts Tvbicb are diecbarged into it by tbe rivers through its entire bulk. Tbo deposits wbicb result from tbe Gonceutration of min- erals in isolated fresU water lakes will naturally par- take artn]e\bft more of the character of tbe salts fur- nisbed by tbe rocka uudery:oing decornpositionj and wbicb are gnidaally water-borae to the deepest deprea- siouB or siak bolea, there to be evaporated and con- centrated or deposited. To auob causes can we cer- tainly attribute the lakes furnisbiug tbe carbonate of soda and suljibatc of soda bo common in tbe desert reg:ions of Nevada, Utah and Wyoming, and the Biilinea producing borus, and tbe nitrates of potaaeium (saltpeter) aud oi sodium (Chili saltpeter) iu tbe same rcgJonB and also in tbe deueits of Soutb America; and tbe bitternesB of Mono lake and other waters due to tbe presence of aulpbate of mafneHia (Epaom Bait).

TVitb sucb an origin it in plain that tbe eiilorescence or crusts of these easily soluble salts aie to be sought for mainly in arid regions, where tbe rainfall is not sufficient to re-dissolve tbem after formation, and that chiefly during tbe hottest portion of tbe year wLeu evaporation has done its work most thoroughly, Tbe presence of these salts in streams ueed not be per*

d

MINERAL DEPOSITS OTHER THAN YElUlS. 143

ceptible to the taste, for even good, drinking watsrs may carry au sTerage of 20 grains of solid matter per gallon in aalutian, but the coustaut accumulatioa of even this sEuall (itnount, if carried on for a time suffi" ciently long, will produce all the phenomena we have been describing.

Alternate Bmporated DeposiiSr — It must oot, how- ever, be supposed that these depoaite are always uni- form in quality throughout. In many localities they consist of fllternating beds of salt, gypsum and clays; or carbonate of soda, salt, gypsum. Chili saltpeter and, boracic materials with cJay partings, laid down as one or other of the materials predominated iu the water supply, owing to changes in the character of the rocks from which the salts were drawn, and varying accord- ing to relative solubilities. It can also easily he un- ieiHtood that they will thin out in every direction louud their boundaries, which are also apt to b© tuixed with impurities blown into the lakes from the dry sandy wastes, or forced in by the sudden rush of water caused by cloudbursts.

Sediment Mineral Deposits. — Besides the mineral salts oftrried in solution by water, it is likely that some bedded deposits owe a portion at least of their contonts to particles of mineral brouebt ia auspeneion by dowin-s water and depoaited, like other finely divided suspended matter which goes to form shales, slutes, etc., when the current whb checked and no longer able to carry them-

Beds Iron Ore. — It is evident that in all these cuaes there is not necessarily any chemical action tak- ing pluoe, afttir the water has once absorbed the matei'ial to be deposited, but euch is not always the case in the formation of iron deposits.

WTiile some iron ore ia formed in lodes, or cavities ID limestone as es depiosit from ferric waters (waters tiarrying iron), probably the larger bulk of iron ilepoeitH bayg Ifoen thrown dowa in beds in the waters

144 PROSPECTIIfa ANB

of swamps or lakeg, tlirougli the alaaorption of osygen from plants and diatoms (iafiieoria) sccopopanied by tbe liberatiou of hydrogen and carbon in the ehupti of gas. Bog iron forms in marshy ground in Buch a manuer at the present day, out of waters ivhioh have become charged with iron, col- lected from the aanda and rocks through which they have traveled; andvlKjre the accumulatious of nodules aud concretions ha-ve been removed, the formation of others shows that the process is still in action. Such deposits will naturally be moet impure round their tnaTgine, as in the case of coal and the njinerala just under conBideratioD, and may range from mere miX" tures of sand and iron or ironstone and clay, up to iron oree of great purity, according to the conditions under which they were formed. TruOj, heat and pres- sure have modified many of them eliminating the water from the brown, and converting them into red homatites, which by atiU further changoa may have been altered into magnetites.

Many of these df>poitg covered so large an area that now that they have been uplifted along with the rocks which contain them, and have lost a portion of one of their edges by erosioDj they present the appearance of true contact veins, and can be worked as such ; but from the differenae of their origin they are likely to maintain a uniform thickness formuch greater lengths and depths thnzi true veins, and also to retain a more uniform constitution.

Beds of Gold, Copper, Siher and Lead Ores, — The formation of beds of conglomerates containing gold, as in South Africa, or copper as in the Lake Superior region; of sandstones eontaJniug copper as in Europe, or silver as at Leeds in southern Utah, or Bhales con- taining galena, has in nowise differed from the forma*- tion of similar deposits in wbiah minerals of vahie have not been found. It ifl only the presence of min- eral in them which calls for attention. The native

r

MIJ!iERAL DEPOSITS OTHER THAN VEINS. 145

copper in both oonglomeratea, gandatones and atuyg-

daloidal traps (or aucieDt eruptive rocks) of Lake

Superior may Lave been eabBeiiuently introduced by

the infiltration of waters carrying copper in solution,

from which the copper was abetraoted by the reduaing

and transforming agency of the iron in the rookg, or

in other cases may have even bean introduoed at the

time the beds of sandstone, ete. "were laid down, and

the aame may be aaid of the grains of galena in Bhalea,

but it must be confeased that the true origin of these

metallic or metalliferous grains is wrapped in some

obsaurity as regards the question of time. The same

may be said of the ahloride of silver asiooiated with

the vegetable remaius in the sandstones at Leeds, the

difficulty here being as in the other caaeg to account

for the presence of mineral io one bed of aandstoue

and its absence from other aimilar formations. We

can ouly suggest that in the Leeds sandstone waters

carrying silver in solution were compelled by the

nature of the etratification to traverse the baud of

sandstone, before its vegetable remains had become

petriiied, and in that condition acted as reducing

stents on the argentiferous waters; or that the bed of

sandstone was formed under such oircumatances, from

J'Ooks containing silver, that the sediment was a com-

pound of both mnteriala, which Eiubsecjuently under*

went a chemical rearrangement through the action of

Pexcolating waters, in which the org'ftuic remains

placed the part just assigned to thern just as organic

natter like charcoal will precipitate gold from its

BolatioD in chlorine.

The useful tnetals other than gold, iron, copper and Bcianganeae (which is also precipitated from sea water drganic remains such as bones), axe, however, derived to so small aa estent from ancient beds that tneir occurrence in them ia more of a miueralogical curiosity than an important problem for the miner. is ohiedy interested in being able to distiuguish

PliOSPSCTIJfa A2fl) VAIUINO MIIES.

betweea a bed and a true vein, op aoGount; of the greater certainty of permsnence in the former and the probabilitiea of its position underground.

Dip of ilineral Bt'ds — As a bed belongs to a aeries of strata which may bave been uplifted, so tliat a por- tion of tbem has become visible on the surface as parallel outcrops there is no certainty that the appar- ent dip of the strata (that ia, what can ba eeu at any one point of exposure) will be the permanent dip of the entire deposit. The probabilitieB are altogether agaiJiat such a supposition, and In favor of a flattening out SB the dip is followed downward toward what must be the center of the basin, of which we see portions of the rim only as in the case of tbe strata seen on the left half of ph 3j fig. 5, or the r]|!:ht hand hnlvea of pi. 4, £gB. 2 and 3. It does not, however, follow that all the strata exposed wiU reappsar when the other edge of the basin is found and explored, because some of them may have thinned out and disajipeard in thd intermediate space, and their place be occupied by otherst or the other edge of the basin may not be aeen on the surface at any point, being covered up by rocks belonging to later epochs.

When strata thua dip together toward each other forming a trough or baain, they are said to be "ayu- olinal;" when they dip away from each other, as in the left hand side of pi. 4, figa. 2 and or like the two sloping sides of a roof they are said to be "anti- oliu&l;" In the former case they may rapidly pass out of the limits of a surface claim and enter adjacent ground, in which they may be reached by ahafta. In the latter ease, they may pasa out just aa rapidly if only a small portion of the top of the anticlinal fold has disappeared and the location be based on an out- crop of the flat top of the arch or fold ; but as more of the fold has been removed the dip will apparently be steepert reaching it maximum half way between the top of the fold and the bottom of the adjacent trough

MINERAL DEPOSITS OTHEHtTSAlf YEIIHS. 147

if tlie foldiDg be perfectly regultir; auch, howeTer, ia scarcely ever the caBS, bub the principle iuvolveil is the same, as can be seen by a study of pi. 'A, 5.

Outcrops of Folded Mineral Beds. — The peculifiritiea of the outcrops of bedded deposits, when there has been folding uf the strata, are well illustrated in rl. 4, figs. 1, % 3 {afttir Geikie), and should be carefully studied by those luaking locatioLB of iron or coal doposita, ae they may load to wild conduaiona as to the amount of ore or coal in the surface esposuree. FJga. 2 art d 3 Bhow bow, by lateral jM'Bssure, the beds laid down horizontally haTe been aqueezed UQtil any one of them presents the appaarauce of a piece of cunuRuted iron, or the troujbB and ereats of b aeriss of waves, the wearing away of the aurfaoe of euch a folded mass the edges or outcrops of the different atrata would be exposed as in iig. 1, of which tig. 2 is a croBs section, on the line G H, uud fig, 3 on the Hue C D B. B forms the synclinal and A, A, tije apticlinal fold of the exposure, the diiierentbeds of which are numbered bo as to be recognizable m each of the iigures. The dotted lines in £tB. 2 and B indicate the position uf that por- tioii of the folds which has been worn away. Noiv, if weeuppoBS the heavy black lina betweBU 12 and 13 to be a depoait of iron ore, it is fnorally certain that the naikiority of pros*ectors would report two veins forking at if, pi. 13, tig. 1, when Juatead of two Teina, preanm- ably dipping into the ground to uuknowu depths, there is merely a trough lying between the two out- cropa, the boundaries of which can be absolutely measured and the area calculated similarly at A 4, fig. 1, two veina would be reported forking in a aimiiar manner, whereas it is merely the saniG sinuous dipping ftway in all directions to unknown depths, and conse- quently more ex.tenBiYe tban the beds B,B but more difficult of access, and to be found below B, B if not buried too deeply under the atrata B to 12 inclusiTe, to be reached by shafts. Th<!se remarks are intended

PnOSPSOTHfG AND VALUIIfG MIUfES,

to direct the Attention of the prospector to the necea- Bity of aBcertaiuiug the dip of such discoveriee at the earliest possible momint, as ft ixupk mattr of self- proteatioj], no tbat he may locate the requisite adja- cent grouud and prevQDt others fiom gathering the larger Share of the fruit of hiu lahora. Even the Bimplost ti]tii:ig of a series of strata, camblned with exposure of the outcrop by one stream running with WiH dip and another across it ms.y present the appear- ance of cross veins, particularly if some portions of the outcrop are covered with dehrie in such a way that it is not visible for its full length.

Caves, efc— Where ore in found outside of fiBSura Ttiina or contacts, the influence of the rock on the form of the depogit is yet more strongly marked. We have noted the intiuence which slates exert on lodea, con- verting them rather into metalliferoua bands of rock, LimestoDes stamp their character upon the ore bodiea by the formation of chambers connected together by thin aeams or pipes. HoweTer irregular the seraea of chambers may be, they must have been formed by cir- culating waters (descending in the example shown by the arrowheads in pi. 6, Jig. 8) which followed the bod- ding planes or jointa, and we must conBetjueutly take these as oor guides when searching for the ooutinua- tion of an eshaUHtcjd chamber.

In this connection it is instructive to note the great similarity between a map of the workings of the lime- etoue contact lodea of Leadville and one of tortuouafl chambers of the Mammoth Cave in Kentucky, carved " out of liraeBtone by the action of water, the only apparent difference between them being that one set of chambers ban been filled with ore and the other Lhs remained open. The latter fact is further of interest as showiuj that it is possible for underground open- in'a of large size to exist, as opposed to the theor.i' advanced by some writera that Huch caves are impois- sible along the lines of a fissure on account of the

Chapter Ix.

Pbospectinq.

Discretion in Taking iip Ground. — Fortunate is the man who Laa the iustmctive ability to recognize a "mino" when he Bees it, and the courage to forbear locating every little seam of ore he may encounter. Nearly every proapeetor ia "location poor;'* loaded up viiih so-called mines, the bulk of wlueh should never have been located; which be Is confesaadly unable to "work, and many of which were simply coDBidered "good enough to sell" when the notice of location was pasted. Ab a general thing, uothiug ib vortb locat- ing, and it is only in esoeptional cases that anything is 'worth working which has not a £rEt-class surface showing either in duautity or quality of ore. "Es- tensions" of good and proved mines may be excep- tion s.

Accurate Observation and DescrJpiion.— It is a com- Taou remark among prospectors when the aurfHoe shoTving is not particularly proniieing that it is only .necagaaryto gain depth to make a mine. We ehaU 800U aee that there is no foundation for such a state- ment, when we come to consider the lesson oi the out- crop. Bat first let ua look at the points wbieh a pros- pector should note about each of hia locations as they are made, so that he may be able to intelligently explain their oondition to thoae wboee aid he may desire to develop them, remembering that all ques- tions which can be answered positively should be ao answered, and that on all other points an underesti mate is infinitely better than an overatatemeut. If a

Jk

pmspEormo.

man examinijig a mine for inveatment finds the repre- sentatioiia honestly and aoourately made the first im- pression (Always an important one) is fRvorable aud likely to rsiuain; but if first one discrepsitey and then another is encountered, a feeling of dietrust is created 'which may break off pending negotiations, while at the same time there has been no iotentioQ on the pt of the owners to make a miBStateraent of facts. The trouble frequently arises from the use of terms in a loose way, so that they convey to the hearer a totally 'different impreBsionfrom that intended by the speaker; or it may be altogether from a of kno-jrledge or misapprehension of the nieaning of certain facta.

POISra TO BE DETEHMINMI.

1. Distance fob which the 'Vets oit Defoset cks bb Traced.-— Not infrequently we are told that the -vein can be traced a mile when in reality there are only a series of isolated outcrops in a more or lees straight line, with intermediate barren or aitparently barrea spaces often of coDsiderable extent. Strictly speak- i icig.the diatauoe for which the outcrop can be followed -without a break is all that should be called traced, but if the vein lie at the oontaofc of two different kinds of rock, and on following this line of junction, even when no vein matter ia visible a second outcrop be found on the contact, both outorops may fairly be con- sidered as on the same lode. The same will be the case if the Ysin is formed on the wall of a dike, in hich case all ore bodies lying on the same side of the dike may be caUei3 parts of the same vein. But ae it eeldom if ever happens that the vein for its whole length is ore-bearing, the distance the vein itself can be traced ia of vastly less importance (except as indicat- iag its strength and probable oontinuanae in depth) than the distance the ore body, the really eeaeutial part of the vein, can be followed unbroken. This length ahould be determined even if it takes some trouble.

152 PnoSPBCTlUfG AND VALUllTG MWES

Following Bikes and Oontmts.- — In tracing an out- crop, or ratbr a vein, nnture oSera itidicatiODB. If foUowlDg a dike, the latter ia generally much larger than the vein and not iofrequently harder than the rocks which it traverses Etanding uj) above them, and can be taku as a guide. If the vein in on the contact of two rooks, and covered ini jilaces ivith earth or debrie, it is only necessary to locate outGrops of the rookg on each Eide of tbe contact, nod the search may safely be confined to the space between them. Nar- row trenches through the Burfaoe dirt, run across the generali line of the lode, will easily locate the contact aud disoloBe the ore if it esists. The process ia called *'ooateftoing" by the Cornish miners.

Vegetation as a Guide. — Sometimes tbe Tegetation on tbe two different rooks, especially when decidedly unlike in composition, is bo different that the line of contact may be traced by it alone. In open countries free from heavy timber, like Arizona, this is strikiugly tbe case. Probably the mo-st distinctive vegetation in those lo{!alitiea )8 the various forma of '*yucca, " of which the "Spanish bayonet is a sample; and the "ocotilla" (o-ko-te-ya). Tbe yucca ia confined to the granite or quartzite rocks, evidently liking a aoil abounding in silica (quartz); the ocotilla ia aa de- cidedly confined to the clay-state regions, the line of contact b&icg often drawn on a hillside by these two plauts as if defijied by a fence; while the aactua fre- quents the limestone outcrops and the areas of erup- tive rocks, in other Tvords, for succesaful growth, the yuccas require quartz, tbe ocotilla olay.and the cactua lime. In the broad washes or beds of summer tor' rents, called 'arroyos/' where the rocks are mixed, all three va&y be found growing if the debria is of a auitable character*

A. fi,BSure may also be defined by th6 vegetation growing on it being different in character, or & line of contact may be traced by the same means, aa in Caji-

WSPECTWa.

fomiH, where tlie rim rock of the gravel channels, even where covered and obeenreii by denae brush (chaparral) can be followed aloug the niouatain aide "by the elderberry bush as, the white flowers of which are very coDBpiciiouB in the gray brush in spring. These buahea require permanent water and have located tbetnaelvea along the bed rock riin where the water in the gravel fion's over it or on the top of the pipe-clay just below the lava cap.

Springs.— A. loat vein may not infrequently be picked up again by examining the aprings along the line of its general direction, as the extent of the fie- Bure couvei'ta it into the moat available underground Tvater-courae, whioh gives up its supply as a spring, if a ravine has out down across it, to the peimaneat water level of the lode.

2, Thickness of the Veik, — Here again there is olten a confuaiou of the vein and the ore body. It is the thickness of the latter which is the important item to the intending investor; the totad width of the fis- sure is only of interest as sugegting a possibility that at some point or other it may be completely filled with ore.

How Measured. — While the thickness of the ore body may be accurately measured at as many pointa as may be deemed desirable to get a fair average,, the width of the veiu (by which is meant the distance be- tween the walia at right tinglea to them, not horizon- tally) may be very difficult to aacertain, and many atatemente are mfide on this score with the best inten- tions, which are misleading, because the parties have no true idea as tu what really constitutes the vein.

Total Width and Ore iTtiokness. Oa the Comstook lode the distance between the east and west walla on the surface In the Savage mine was fully 1,000 ft., of which only a small part waa quartz and of that only a portion was available ore. The width "was about the Mme at the Choilar-Potasi iniue, some IjfiOO ft, to the

3utb, vtith several qaniiz bodies cropiiiu parlel to other, of ivliich pi. 2, fig. 2, will give a fair idea in cTOBB section. These were at fii'st euppoaed to bs separate veins, but at about 330 ft. below the croppiugs the Savage mine was reduced to a width of 800 ft,j nearly all waste matter atid the OhoUar-FotaBi mine to a width of 150 ft., all quartz, of which about oue- quarfcar waa ore.

Veins on Diken.-lTi oases where tho ore foriQB on th walls of a porphyry dike (aa in many of the miues of the Monte Cristo district, in Waabitigton), the pi'oepector generally calla the entire dike the vein, giving it a width of ttom 20 to QQ ft. or over because he may be able to £ad traces of iron pyrite in the more decomposed portions of the dike, the bulk of which ia, however, unaltered rock. Obviously the vein is only that portion of the denomposed dike which has been replaced by ore. To give the entire width of the dike as the vein, will create a very seri- ous misuuderBtaudingjaa it ia scarcely probable that it will have been couverted. to an ore body for its full thickness, at any point of its length.

False and Indiatinct IValh. — Id other cases, where there has been much motion in the tiasure, ite walla may have become much shattered and rotten, forming a series of slabSi eaob of which may present the smooth face of a true wall* even to the slickenaides, but which will peel off one after the others, after a ishort exposure to the air, laaking it diffioult to state positively when the true wall is reached.

In slatey rocks there may be one wall well defined (if the vein is a contact) while parallel bodies of ore or barren anguft mny lie in the elataa for Beveral hun- dred feet from, the contact (pi. 6, fig. 1), as in the mother lodo of California. Under these circuQjstanoes it ia better to give the width of tbe ore, and if there is a decided difference in its appearance, the width of each portion, taking samples as desorihed in Chapter

n.

PRosPEornm.

If the length and width of tbe ore bodies as they ahofv on the gurfucG were aBcertained in this manner, a large number of ]uaatioiisvould be abondoned, having failed to stand the tst of working \alue; and while the prospector would have fewer locations on hia bands, be would be saved the burden of the annual aBBesameut work on ivorfclile&B properties, and he could Lonestly ask capital to aid the development of those so carefully selected.

3. fcJAMPLEs OF THE CouNTRy EocE. — While a study of the chapter on rocks will have enabled even a beginner to speak of them with something like aoou- racy, it would be well to take a small hand sample of the rock on each side of the vein. "We have seen what important diSerenccs there are in the shape of deposits Iq diifferent rocks, and one of the first questions an expert will ank is on this subject, as. it aCfects also the cost of working moat eeriouslyj a drift or shaft in soft slate Gostiug very much less than one in hard granite. Should there be a doubt as to the judgment or knowl- edge of the proEx>ector the specimens will speak for themselves, and are nearly as important as the ore eamplos. These samples need not be taken immedi- ateJy from the vssWs theiuaelvea as in euch places the rocks are usually greatly decayed and unyecognizable in small pieeee. It is better to take them a little dis* tuuce from the yeiu (say from the nearest outcrop iu place), as these are likely to be solid, being harder than their neighbors, and while taking these samples to note whether the outcrop of the vein ocours in a country' which ia badly broken up, or wbethear the hilla are large and smooth. The latter appearance promisea better than the former for a solid contiuuDUS vein without displacements. In selecting specimens the prospector should also ascertain whether the vein runs parallel to the general direction of the rooks, or whether it cuts across the formation — features whioli have an important iniiuence on the probable perinft*

pnoBPEcrmo and valuing mines.

nence of the lode in depth, the latter structure almost necessarily iuvolving a deep fissure of considerable Itnth tiB well as depth.

The namea of even the common rocks seem to be a continual stumblitig block to most proapectors, appar- ently fur no other reason than a failure to r>6ali!(e the fact that Bach kind is made up of a definite combina- tion of a few micGTfllB. It would seem as though the ti'oubie of learniug to distinguish from ten to twenty kinds, which is about all that ie necessary, ought not to be such a serioue matter. Every business has its own language, and those who ivisb to ecel must necessarily learn to apeak in a language hiob will oomrey the same idea to all bearers, and each ord of which will convey a positive idea, instead of a hazy nothing. The writer recently met a prospector who bad some fair-looking sijecimens of ore, but when questioned about the mode of occurrence and the lay of the country, in an effort to get an idea of the facili- ties for working, in reply to a question as to whether it was a granite country he answered ''Yes.*' "When asked if there waa slate, "yes" was the reply. And to fully satisfy any further inquiries which might be msde for other rocks he added, "There is s regular jumble of tbeml" If this wbb really the case he had condemned his property, as such a condition QGcee- aarily involved a badly broken country, but it was evident that he knew nothing about the subject under diacutjsion, while he simply casi a doubt upon every other statement he had made, gbowiug that he wag not a good observer. To make things worse he subse- (luently inquired what basalt was worth, and when in- formed that it was merely a black voleanic rock with- out value for any of the precious metals, he gently intimated that his ijiformant tmight know what he was talking about, but that he had his own opinion on the subject. His basalt proved to be orpiment, a yellow compound of arsenic and sulphur.

L FAOiLiTiEa FOE WosKiMG.— The faculty of locality,

whioh muBt be well developed in a proftpector to

dnable bim to dnd his way through the wiidernees,

will usually also enable him to deHcribe the best

routes of ftcoess to hie property aud ivhut ran be doue

or baa been done in the way of truilH aud roads. It

nil! also euable bim to answer questiona as to the

Hupxdy ot tiiuber for miuinu imrinjseB (a taoat itnpor-

tant item) and for fuel if coal ie uut accessible, so

that the wuter supply and the chances fur economical

<l€Telopment are the only ijueBtioDa to -which we need

allude in detail under thia heading. If fuel is scarce

nd water abundant, the latter may furnish thetuotive

t:>OTver if the supply can be used undtji preesurej either

3lireotly or through the usa of electricity, and to enable

he prospector to readily eetimate thia power, a ehort

<=bapter has been devoted to the measuretnent of

'Xvatsr, and the method of calaulatin the horse power

"rhich a given quantity will develop. This depends

on the quantity and the fall which can be secured,

:xDoditied Bligbtly by the distance it baa to be taken to

eequre the fall so that the proBpector should be able

to acswer tiieao queBtions approximately, A mfcaaure-

3uent of the supply taken in the dry seaiion is most

desirable as giving the supply which can be depended

on all through the year without the use of reservoirs,

which are costly and often impracticable.

lu not a few miQing oampa water is scarce during the early stages of development, but while this scarcity may iucreaae the cost of the earlier work, the defect is oue that usually remedies itaelf before any (WDfiiderable depth has beet attained, an abundant supply being generally secured from the ehafts and tunnels, oven if the quantity does not prove excessive — as in Tombstone, Ariz., which in early days was a notoriously dry camp.

The manner in which the vein can be opened to the best advantage wilt depend on the shape of the conn-

PliOSPECTIIG AND VALUIIfG MIIfES,

try and the way the Tein croases ib. If flat, shaftt must be reaoi'ted to; if hi]\y, it maybe better to adopt tunnels if they chd ha run on the veia, and the pros- pector should iuforLQ Jiiuiaelf thoroughly whstlier this can be done to advuutage wliich will depend ou tbe positiou of tbe outcrop. This question is more fully treated iu Chapter XII., on early developtuentj aud attention is mereJy called to it here, as one of the things ou whioh all possible information should be acquired.

5. LiaaoN op the Odtcrop. — All the foregoing remarks apply only to the eurfaoe obgerrations, but in stutlyijag the outcrop we may gain some insight into the probabilitieg of depth.

Fr.iient Appearance nol ike Original — The first necessity is to disabuse the nDind of the idea that the veins were all formed after the country had assumed very much its present shape and appearance. The remark so commouly made, that a vein which shows poorly on the surface will improve with depth, is based on thin fallacy, the underlying idea evidently being, although probably not even thought out in the mind of the speaker, that the ore at that particular spot had not been able to reach the surface, a notion aa- Bisted by the other false iJea that all the filling of the veins had been squeezed into them from below.

As a matter of fact there has been an immense change in the surface since the majority of the min- eral deposits were formed. In the case of coal iielda originally laid down horizontally and subsequently tilted to steep angles, whole sectiouB of these fields have been worn away along with the inclosing rocks, or we should have no outcrop of them. In California we have absolute prtjof that the rocks which carry the gold veins have been worn away In places, even since the eruption of the basalt lavas which tilled and cov- ered up the old river channels to a depth of fully 2,000 ft.j aa in the cations of Slate Creek, Canon Creek

Prospeutinq.

and otilieTS in SieiTa aud Plumas cauutieB As theeQ old river chaonela cany gold, in fully as great a quan- tity as the luoderD placers, which must have been derxTcd from the wear and ter of tbi3 bills ivLicb formed their tianka, there mast have been exteneive erosion before the flow of the lava, to carve out these ioiiQeDse valleys, &0 that ivo may add au uiikDown quantity to the known 2,0U0 ft., and i.rohably be irithin limits if we estimate the degradation of thG Daountaina carrying the gold veins at 4,000 ft. or over. Vritere on AbyBsiiiia state that in the approach to -llagdala gorges 4,0€Q ft, deep have been cut down "tlirougb the basalt into the underlying rocks, Jeaviug itlie basalt as table lands, much as in California, and ii gold veinB traversed the rocka of the Grand Cafion of the Colorado we should have their secrets esposecl 3,000 ft. below the top of the plateau, tbroub which "tlie river has carved its stupendous orge. It is there- fore evideiit that in the great majority of cases the <Z)utcropa of veins may be called purely accideiital ex- pOBureB, which Lave been constantly changing in their *ippearatice for thousands of years.

Increase or Decrea.e in. Dep[k. — The erosion or

"wear and tear by air and water may Lave proceeded

3uat far enough to xinoover the top of the ore body, or

at may have progresBed bo far that nearly all of it maj*

ftve been removed. Are there any evidencee in the

utoropB themselves as to 'which stage has been

leached? Before entering on this questioti, however,

let s\& look at the probable mcreaee or decrease in the

value of the ore in depth.

In the ease of veins which oany large quantities of Bulpburetted ores which are easily decoiuposed, such && iron and copper pyrites, we may espect a deorease in vftlue on reaching the permanent water level of the mine, below which the decomposition will not have extended. If tbeee iron pyrites curry old, the gold will have been liberated by their decomposition, and

160 PHOSPEUTrnG AUD VALUING MINES.

will accumuUte in the CBTitiee of the ruety quartz; ami ae the ora after the removal of its enlpbur s,hd part of the iron is lighttur, bulk for bulk, than the UDdcuonipoeed sulphides below 'n'e hsTe s, greater bulk to tbe ton aud also an eDrichcd iDaterial. so that awaaye of the eioppings are likely to be better than CHti be had aftei' tlie waki' level is readied-

In coMJer veine tbe decomposition of the copper pyrite regiilta io tbe foriuatioD of tli6 red and black uxideH of copper (juat bb iu theformar case tbe product of decojuiiositioii was oside of irou) both of wLiob are richer ill copper ptr ton than the etulphide; and aa they are practically concentrated surface deposits, not extendiiig below the water line and may result from the decay and leaching of very poor oreSj we bave another instance in which the vein would be poorer in depth.

But where no decomposition bas taken place there Ib little or no proof of continuous improvement in depth, and more probability' of impovtjrisbment of the veiji. If tbe former were the caee the improvement ought to be coutiDuouBand there "would be no limit to the increase of the deposit, vbicb wo know Biot to be the case; and it is more thau likely thsit the quality of ore variet) greatly in nearly all instances, laonietiiues improving and sometimes growing poorer as tbe earth is penetrated, being governed very largely by cbacgea in tbe character of tbe rocks traversed by theveiu, and accidental couditious which wb bave not yet learned to realize and understand.

But tbe prospeetor need be in no doubt on tbis point, iia in moBt cases be can satisfy biraself from personal examination as to tbe facts. If, as has been stated, the deposits were formed when the country was more elevated than at present, any ravine cutting acroaa a vein or deposit explores it naturally ab we do artificially by sinkinf? a shaft, and if improvement fol- lows witb increased depth, the outcrop at the bottom

the ravine ought to be richer than one on the fiunj- lait, as a descent of 100 ft, verticsJly below the top of the ridge would be equal to the 100 ft. level of a shaft sunk on the outcrop — 200 fb, would equal the 200 ft- level,and bo on. How little Ihia accorda with eiperi- ance every prospector knows.

Nothing but actual work can poaitively determine the question whether we have merely the tup ur the tail end of an ore body, aa if we look upon the ore body aa a roughly shaped lens two parallel lines til-awn tbrougb it one just below tbe top and the other just above the bottom, would each cut oft a por- tion showiug the game width and length; but if the ore ia aoftnr than the iuclosing rock, and the vein crops in the bottniH of a deep gorge, there is every probability that the sorga haa been formed by the wearing down and removal of the ore body, that the outcrop found, if of small dimensions, is dereb* tb© lower end where the increased portion of country rock resisted the actioo of tbe atruam to a larger extent and stopped further erosion. In a similar way, if the out- crop 19 on a steep hillaide and of only limited length, it tflfiy in many cnaea indicate the termination of the ore body, as tbe erosion of the ravine which has ei- p06ed it has also disclosed some of the secrets of its peuetration in depth, as iuat described in discussing th Liuality. But if the outtirop is of considerable length and thickuea, this q.ueation Deed not trouble us, as there is sufScieut fusti fixation for the expendi- ture of considerable moDey in development.

Tbe condition of the mineral in the outcrop may also furniah a slight guide as to probable pertnanenco in depth. Some of the common minerals in orSj, especially the several varieties of pyritSjare easily de- composed under exposure to air and water, and where there is evidetice in tbe rustiness of the outcrop, or the presence o£ a spongy looking mass from which the orystals have been perfectly removedj we m&y cer-

Ifi3 FSOSPEOTING ASTB VALUING XmSS.

tainly infer that the clraiuage of the vein extends to Bom6 ilerth aud involves a contiuuouB iQsaure, as it is only by the presence of Bucb couditious that the de- compositiaa could have been eHectoJ. But if the pyrites remain in the croppings entirely undecom- posBd, vea may iiifur that the walla of the fisaure nre eo tightly ia contact below as to prevent the percolation or sotipatse of water downward, and this may be taken as an unfavorable sign.

In Boft and easily decomposed ore bodies the removal of the outcrop running along the face of a hill instead of scuobb it may reault iu shallow depres- biohb, iijtead of a conspicuous ridge, in which the ore can only be found by dife;ging; and when the ore is of this ebaraotet, the aearoh for it becomea a very laborious taak, especially in moist and wooded coun- tries, where the vegetation may be eiceedingly rank And tangled.

Fluai. — From what has been said of the origin of veins and the anhflequent curving ont of the ravines and valleys as tliey exist to-day, it ia evident that there must be on tbo biHsides and in thy ravijjes of a coun try rich in minerals, many fragments of mineral detached from the ore bodiee. Ibese are called "float," and it is equally evident tbut the harder the material forming the gangue of the ore, the larger should be the number of fragments which have escaped the destructive action of air, front, water and sun- shine. Such miuerals as decompose very readily, or are escesaivBly britlle njay disappear altogether, or nearly bo, as coal ursome forma of galena; but quartz- ose varieties may survive a long journey aud be found at Gonsidorable distances from their original source. Large fragments indicate this source to he much nearer than ftmall ones. Gravity has constantly car- ried tbtise fragments to a level lower than their source BO that when tracing flout, as eo often dune, we look for this source above the place at which the float has

PnOSPEOTINQ.

1G3

been found- It maj'have reached this place either by rolling duwn tLe hillside iii the iiaiiuediHte ceighboi- Lood, or it may have been carried do%Yii the hed of the raTine hy The position of the Hoat will gen- erally indicate Tvhich has been the method of trans- port, but iij either case we must traee st upward, and if we tiiid the fragmeuta increasing both in number and in size, wo may coucludo that we aio neaj'ing the source of siijiply. Sunietimea these niuy lead to the dJBCOTery of n'eU-Jefiued lodeB, tind again in the case of tiuiartz, we maj' finally lost all trace of it, without eneountei'iog anything of vnluo. This is eKpecially apt to be the case in eliiite countriee, which have been crushed and crumpled and suToaequently filled with innumerable thin quartz seams'. All the float may have been derived fiojn these seams, and the float ceases because we have reached the limit of the slate formation, and enter a new series of rocks without quartz. This structure explains numbers of caes of "lost leads," but while there may be no well-defined vein or lode at the point where the ravine cnta the formation, if h*e been found ia the flout it ehow thut the reiion is worth iiroapectin and the eeuruh should be continued along: the line of cuntiict of the rock which has cut out the metul-beai*iu series. TopO'jraph]} and Wair /S'ysfrnt,— The reverse ia just as likely to be the case where tlte ore body is soft, as nature always carves out a country on the linea of least leiatance, which may ha lines of faulting, or contact of a soft and a hard rock or through soft ore bodies or between coisoHdated hax'd ones. For reason the study of tbe water system of any particular mountain region affords a good insight into its phys- ical structure. If nil rocks were of uniform and equal bardnesa, the face of a country wouKl be planed down to uniform smooth slopes. It is the varying resist- ance of rocks which diversifies the mountain regions, in combination with the dislocations they have under- gone.

Prospecting Asp Valuing Mines,

Genebai, Eistb,

Wht to Looh for.— The importance to the prospec- tor of koowing Bomething about rocka becomeB appar- ent. Iq a granite country it is evident that lie may expect tiu aa well as a Toriety of other jniuerala, and HboulJ cODsc<iU6iitly know the orea of tin (and tfaey often, do not look like metallic ores) bo as to be able to recognizB them. In a iimestooe belt galena, iron anii zina are Bpeuialitiet]. In a country made up of toI- canio and eruptive rocks, it is uaelesB to look for coal; i but in such a country, where a belt of hot springs foKow the junction of eruptiTe rocks, eBpeoially basalt, with a group of sedimentary strata, the ores of quick- eilver should b6 in his miud. In a belt of hornblende rocka he may devote hie energies to aebestos, soap- atone and chrome irODj as well as to the precious metals, and in sandetone aud ehale regiona the out- look ebould be kept for cDctl, fire clays, iioUj rock Bait and gypsum. In a coal belt it is almost uaeleea to eipBct mineral veinSj for apparently no fiasureB made through a coal bed carry ore in the rocks abore the coal, ivhatever tbey may do below. Any one who will take the trouble to put down the mineral occurrences in any extended region will soon discover that tbey resolve themselves into a series of belts corresponding with the rock forroation of the country* indicating moat unmiti!tHknbly tha little understood relation be~ tween them. In the large basaltic areas but little of interest or viUue need be expected, except such min- eralB ao opaL etc. ; nor is it any use to search for the soluble minerals, such as saltpeter in any but exces- aiveiy hot regions of depreaaion, without drainage out- lets, and Burrouuded by volcanic or eruptive rocks.

Where, to iS'rorcA.— Above all things the proapec- tor's aenroh should first be through all the nccesaible regions of a mineral country', for in such districts a much anaaller ore body and a nnich lower grade of ore may be more valuable fiufiuciaUy thau greater size

ricliseaa in leas Accessible localities aioid moun- tain faatnessefi and eternal snovs. It is time to enter itbeae heu all otherB are exhaustei, though, their fas- cination is so extreme that it is to tliuni that tLe hope- ful adventurer firsb directs his footsteps.

.Prime liequisites. — "What ie wanted by the capi- talist IB a large ore body, fair average quality, good working faeilitieB aad reasonably eaej' access, Givea these, there is usually no difficulty iu securing all the capital necessary. Tbe Tant of any of these Qualities in the mine renders the task more difficult.

OutJU. — The extent of equipment will vary accord- ing to the character of the country to be traversed, 'the distance from supply points, and whether tbe lrospector hs any means of conveyance eutib as a taok horee or burro, or has to carry everything him- eelf. It is unnecessary to speak here of clothing, tilankets, food, etc., further than to say that the lined snd riveted canvas suits are perhaps the most service- able, and that comfortable as well as strong boots sxe sn important item.

Among the details of equipment the following may Tbe mentioned. The horn spoon is preferable to the £old pan or batea for prospecting:, as being more con* lenient to carry (it can go in a pocket) and in use requires very little water, and does not fatigue tbe "uaer by causing prolonged stooping. A small bottle quicksilver will bo found useful when testing for 'old in a very £ne state. A computes with folding Bights and a3-in. needle will help in laying off ground and couoecting a location with other monumenta or landmarks. A tape is not necessary, as one cau be improvised from well stretched linen cord, standard- ized by BoniB measure before starting and knotted at 1 ft., 1 yd-, 10 yds. and 50 ft. long. If a regular tape is taken that with steel wire interwoven is preferable to 'ft heavy steel tape, or a small self-winding narrow Bteel tape oan be bad, which occupies less than the Bpaoe of a watch A eiuall bar magnet is useful in

PROSPkCTINQ AND VALUING MINES.

cleaning up panniKis. In tbia conoectioQ it may be noteJ that in tbe abeen<;e of li regular gold pan very good results oan be obtaiaed -with almost any aort of a receptacle, such aa a frying pan, tiu dish, etc For testing Buiphureta and dark iJiinei-alH generally a white aurfacQ is preferable, Buch as that of a eaJicer or Bmall bowU in uaitig which ivhn taking eamples from a wet- crushing battery oare tuuKt be taken to avuid ovetjUow Hud coneeq.ii6Ut coiiceiilration if quantitative results are wanted. When sanapling placer ground two buckets are very huady, to be used by waating from one to the other. To examine ores, float, pnu or horn residues and rock minerals a lens is almost inUispeQS- able, and the amall powerful Coddington style ia pei- hapa beat. It can bu bung to the watch guard.

Every prijspecttir oughfc to have some knowledge of the uae of the blowpipe in determining ores and min- erals and making rough qnautitative asBaj'S, Tbo whole blowpipe kit necessary cau go in the amallest size cigar bos. The cheap black blowpipe an&wera as well as an expensive platinum-tipped one and a tallow candle is for most pui'poses hotter than the alcohol or oil lamp The half-dozen reagents suggeat themeelTes. A small Btreak plate should be included in the kit.

As 60 taols the selection will depend upon meaaa of carriage and whether any real opening work is intended. In prospecting in a bare, rocky country where no diggini is required, a light poll pick, with say a 3-lb. head or even lighter, is generally auffi- cient, as this tool combinea pick with hammer. Eegular geological hammers of peculiar abape and special steel can be bought or made by any good blacksmith, but are rather ornamental than necessary. Of course if there aro two or more in th party each should take a different tool. If there is a pack animal, then a light working pick and small ahort- handled shovel will be taken.

However, rts to all these mattera prospectors of any experience do not need to be told wliat is neoeBsary.

Chapter X.

Making Locations.

The object of making a location on a piece of min- eral grouud 18, in the first plac, to give notice to all 3ther peraona tbat the locfttor has found mineral herein, and lias made a claim to a definitcj portion of ~ftbe deposit and a definite aninunt of ground to work at to the best advatitage. To aecure this object ho 3:)OBta on the mineral deyogft a notice of bis t'lnim, to filed for record with the proper authorities at a 3at6r dftte; Asd erects auoh monumenta as will define tbe limits of the ground claimed Tbia notice and the monuments secure to the locator a possessory title, which is good so long as the requirements of the United States governmeat, liud tbe local laws of the particular mining district in which the cUim iti iooated, iu regard to tbe amount of work to be done on the ciaim a,nTiualI and other coiiditlojia, are complied with. The ultimate object of making a location is to 'Becure a patent to tbe ground from the United States, if tbe property prove to be vortb ths espense.

What is said here applied to the publio domain of the United States, in the far IVeat. In the Easfieru btatee and in foreigrn coimtriea the practice is differ- entt &nd local regulations must be studied.

The basis of all proceedings to acquire patent to mineral ground (see Cbap, XI) ib a duly certified copy of the notice of location and tbe monuments which it deecribes.

Gover/nneni Requirementn. —The in struct ion a Is- sued to tlie deputy luineral surveyors, to whom tlie work of making surveys for patent is intrusted, are of. the moat stringent character. Under theee instrtLc- tions, the surveyor has to report the true pasltion of all the original monuments, or give good reason for their Hbaence which viH De acceptable to the exami- ners of the United States laud office at 'Washington; be must muke the end lines of the claim parallel (if it be a lode claim); and he must not include within the exterior lines M the survey any ground outside the corner' monumauta. "Whether this always does justice to the locator is not the question; it is the ruling of the department and must be re&pected. Neglect to restore monuments in the spring which may have been destroyed by winter Btorme, may result in litigation and endless delay in securing title, as their presence is the only thing which will debar a second party from coming on the ground and making an adverse loca- tion. It is taken for granted that a person making & location will look for monumeute as a sign of previous appropriation of the ground, and their ahsenoe justi- fies the supposition that the ground is vacant and locatable, or if previously located has been abandoned by the earlier claimants. A locator cannot plead igno- rance of the absence of his monuments, hecauee as they are the sole wituea&es of the limits of Lis claim, and the essential meane by which he holds possession, it is his duty as well as his interest to see that they are maintained m good order,

Imperfecl Locations. — The number of locations which satisfactorily fill the requirements — that is which have all the monuments standing and eo locftted that upon survey they will not esiclude some portion of ground to which the claimant feels that he is honestly eutiUed. beoause the location was made and held in good faith — is eiceedingly small- The majority of original locations are very imperfectly made; not from

lack of good iBtentioiiB on tlie part of the loflator, but from want of knowledge aa to wlint is required, or how to do a, or tbelHck of proper instrumeutB. As at present iuterprcited, the instmctioDB iagued to tbe deputy Burveyora really call ior nearly as fj;reat accu- racy on the part of the prospector wbeu making bia location &B they do from the deputy when making the final survey.

Theoretically the regulations are based on the idea that in parting with the absolute title to the mineral Inda (which until a comparati\ely recQt period wsro regarded as tha inalienable property of the crown) the government ia doing so ou suob extraordinarily low and favorable terms that it has the right to demand from the recipient of its bounty what it considers to lie nothing more than a very moderate expenditure of ime and money in return for its liberitliti'. If the oxiginal location has bean carefully inade, and the monumenta equally carefully maintained, the appli- cant for patent will have no dicuHies or delay iu the laDd office proceedinge, as 909 or over of all such -troublea ariae from defeotive locations or the absence ef monuments whioh the government oluima should be in existence. A large proportion of the remainder are delayed by the imperfect charficter of the work on which the right to patent ie bused.

There aeems to be a popular idea that it is within the Boope of the authority of the deputy surveyor to restore such monuments as are missing, at the dlstauce called for hy the notice of location instead of in their original position, and not infrequently an implied feeling that he ought to do so because he had beeu favored by Belection to do the work, and most deputy surveyors can testify to the difficulties bich arise from this source, between the applicant for survey and the officers of the government, in which the deputy receives no support from the government and is very likely to eeeure the displeasure, if nothing more of the applicant.

Prospmctwg And Valuino Mines.

What Can Be Located and in What Mankee.— " Knowing; then what is required by the governmeut, let ug proceed to make a good Talid location, or rather aee wliatiBUQceaaary to make it good,> first at&tiug th&t the etra time iieoaasai'y to conyert a defeotive looa- tion into a good oae is ao smail as to be of no conse- quence wlieu oompared with tbe subsequent aaving- of time money, and annoyance; remembering that if tbe ground ia worth locatiug at all it la worth while to make tbe location absolutely seonre.

Mineral Mud be Found, — No valid location can be made until mineral bae been found within tbe limita of tbe claim in tbe condition required by the charac- ter of tbe location made.

Placer li/catiomi may be made on ground in which valuable njiuerale, suob &s y;old, tin, jilatinunij Iridoa- mine, etc, are mixed with Bind, gravel, clay or bowl- ders, tbe minerals having been removed by natural oauses from theif original positioLi in the rock in place. Placer ground on unaurveyed land luay be taken iu any shape which the locator desirea, provided the ground contains mineral && described, and pro- vided the area does not esceed 20 acrea to each locator or 160 aores to an incorporation- But if the land has been surveyed by tbe government, the claims muat be made to oouform to the amallest legal subdiviaiona (which in tliiB case islOacreB), the limits of f;he placer ground being first determined, and then so adjasted on the margin!) of the location that 10-acre tracts bav- iDg less than five aeres of placer ground are excluded, and those having more than five acres of available ground are included When the final survey for patent is made on unsurveyed land, it will be made to conform to the original takes or monuments, no matter how irregular the shape of the track may bo, regard- less of anything except area, and thia if iu excess, must be cut down to the limit allowed by law. When the ordinary land survey s are extended over anoh

Making Lqca Ti0N3

areas the eecttioii lines ar adjusted to sach eurvey, just as ia the aatae of lode claims.

Lode Locations. — In tlie location of mineral veins or lodes, wbetber they be of gold, silver, copper, lead, iron, tio, quickBilver or -other minerals fouud io lodeBj the United States laws rant to each locator the right to take iu oae location not more than 1500 ft. in length on the lode, and not more than 300 ft. on each ei<le of the center of the lode. A location caimot be made with 200 ft. on one side and 400 ft. on the other. There is nothing compelliug the locator to make his Jocutiob 600 ft. wide, the law simply says he may &o snake it.

Local Regulations. — Within these limits the width da optional with the locator, and by the action of a luly orgttnized meeting of the miners in nay diHtrict, anay bo limited to any quaatity tiot less than 25 ft. on aGb aide of the ceuter of the lode, making a total Tvidth of only 50, instead of GOO ft. In Bodie, Cal., :Jor instance, the width was fixed at 100 ft. on each fiide of the center line.

The local laws of a mining district may impose any other ctinJitions which the miners muy eee fit pro- vided they do not grant better terms than are offered by the government. These miiy be juat as inneh more stringent &h the miners may think desirable for the yolfare of the diatrict, aa, for instance while the United States lawa have been couBtrued to grant the locator otte year from the first day of Jannary succeeding the ate of his location in which to do the SlOO worth of ivork by which he holds hie title, the district laws may 'decide that work shall be commenced inside of 60 or tiy other number of daya, or btipulate for other evi- en COB of good faith on the part of the locator; but tliey cannot legally declare, as is sometimee attempted to be doiiBj that a shaft 10 ft. deep, which only cost 60, shall be considered full value for the required Axbual expenditure of $100. a propositioit is

PROSl*SCTIJSfQ ANJ> VALUING MINES.

always open to oonteBt. As the want of roads often greatly retards tlie opening of otherwise promieing uiiniDg camps, a clause might very suitably be addtid to many local laws, stipulating that each location pay annually a definite sum to some authorized agent to accumulate as a road fund, iu addition to the 1100 work required by the government, but aneh payment could not be made to constitute a portion of tbe annual assesement wafk.

Mineral '"in Place," — As previously etated, no loca- tion can be made which will be of any value until mineral has actually been founds and for a lod loca- tion it must be in the undisturbed rock, or "rock in place." Monuments or no monuments, any outsider can prospect over such a lode location, and it sue- oeeds in finding mineral in place before the earlier claimant, he can make an adverse location and will surely hold the ound- In Leaiville, for inatftnce There the ore did not crop on the surface (Ij/ing nearly horizontally), the ground was covered with overlapping locations, but the &haft which first got down to and struck the deposit took the ground ae against the other claimantH.

Agricultm'al and Timber Bights. — No mining loca- tion, either lode or placer, or for iron or for coai, can be made on any ground for which a patent bas been iBsiiedj unless it can be concIuBivelj' proved that the party obtaining such patent was aware of the esistenee of mineral on his claim at the time of "proving up" and falsely swore to the contrary. This applies to patents to agricultural and timber lands. Alodeclaiu can be filed over a placer claim, as lodea are expressly exempted from placer patents, but across such placer claim, the lode camp has surface ground only 25 ft. on each side of the center of the lode.

Locations can he made on all other olaaseB of land, provided mineral has been found thereon ; but when made on land valuable for timber or agricultural pur-

Making L0Catiok8.

posea, are liable to conteBts before tbe land ofSce ta det6nQ]n6 wljether the ground ia more valuable for mineral or for other purpogea.

Monuvients.- — A monument should be conapiouous enough to be readily found. According: to the char- aotor of the region, it way be either a tree with the side blazed; a email aapling out ofE about 4 ft. from tbe ground TOith the top squared; a iimpleetak'6 about 4 ft. long squared at tbe top, nud driven not lesB than 12 in. in the sfrouud, if there are no rocka ooDTeuient; or such a stake with a rock mound at ita base or even a simple pile of rocks where there are no trees.

Tree or Stake Marlrs. — In all caeee where a tree or etake is used a auflScjent spsoe should be smoothed on wbich to write the dosignation of the corner intended to be represented. If a tree is used it is not suffi- cient to simply bark it, beoause trees in fulling often skin the bark off eaah other in patcbeH, and such a "blaze" ia easily overlooked; but the blaze should be made as in pi. 15 figa. 1 and with a straight uotch at the bottom,, cot well into the wood and dre'Ssed Bmooth to write on with a soft peociL Fig* 1 shows the front view of a proper blaae and tig. 2 the side ap- pearance. Such a mark is unmistakable and immedi- ately suggest the prior presence of men, which the other method doea not.

Sione and stake monuments are easily overturned and destroyed, especially in snowy altitudes JiDd on fiteep hiUeideSj but there woidd not be half much trouble in keeping them in good shape if a little more care were eserciaed in building them. They are usually a heap of rooks, instead of a monument. It takes no more rocks to build a good than a bad one, and but little if any mora time — all depends on the manner of placing tbe stones. If the monnment ia to contain a stake, this should be driven solid, v-ith a rock for a hammer if neoefiaaryj and the criound roughly leveled o£E with the pick which tbe prospector

174 PnOBPECTING Alin VALUING MINBS.

always 4:iarrie&> go as to et a good fouudatioa. This is all iiuiioit;iDt on a hillsiile. Tjie ueoeseaty supply of rocks sbauid then be got togefcber, before startiu] the Btruuturo. Tbo biggest and dattest should be laid in a circle rauud tbo intake at little distance from it in Bucli a way tbiit their upper surfaces slopo inward totvard tbe atnke. By taking this precaution ivith the bottom the aest layer will have a tendency to elide in toward tba stake, thug tuakmt it almost im- poBsiblo fur tbe inonuiueut to tninble down wbile the stake will be wedged tightly in place by tba preaauro; aud if tbis principle is applied uutil tbe monument la completed, imy three courses, with the Itiner apace filled up so]id with small rocks and dirt, there need be no fear of ity destruction except willfully or by snow- slides sweeping everytbiog before them. If the latter are feai'ed it is best not to have the oeutrai post too high, as it will then oSEer less resistance to the oyer- turniug action of the snow. Pb 15, figs. 3 and 4, show ft properly and an improperly built faouument in orosa secfciun. In the latter there is every chance for the momiinent tu h\W apt*rfc and release tbe stiito from its position. Every stone iu a monument should be moved about until it has a pe'fectJy solid bearing, and does not wobble.

Simple lioL'k Monamenls. — In building a monument of rocka alone, the importance of a good foundation is even greater, fur tbe absence of tbe oeutrai stake in- creases the liability to destruction, A moderately large base tapering aomewbat rapidly will give the greatest stability.

Inspection of Monunwnf.s. — To emphasize the im- portance of building well, it will not be out of place to repeat that the owner of an unpatented claim should at least annually examine the corner monuments, and see that they are stendiig, for as they are often the Quiy means by which a stranger can have knowledge of the esiatence of a location ot ita osteutj and tbeJr

Making

object IB to give notice to the world of an esiating claim, their nbsence givos tlie strger b perfect right to locate the ground as vacant lands of tba United States.

Notices of irOcoMJi.— These should accurately de- scribe the monumentis ae Bctually sel Proapactora frdtiuently take out a set of printed blanke in which a "mound of Btouea" is usually called for, and then Bimply fill iu the blank spaces ivith the number of feet located, vheu it ofteu happens that no mound of etonea was made, but a tree blazed, or a small eaplia cut oflEj in places where there is a scarcity of rocka suita- ble for a monument. Frequently the stake called for does not exist, and the writer has seen cases where the monument, bo called was nothing more than a small piece of a broken limb stuck in the ground, without any notice of That it was intended to represent, and absolutely not recognizable as a monumGut, and thia iu the midst of dense timber. Such negligence is inexcusuble attd if trouble arises the locator has so foue but himself to blame. It is, of course, allowable rto use one of these printed blanks to make and post the original notice at the point of discovery, to hold the claim while the diacorercr may be patting up his end and corner nionunieutt:, but the fiaal notice, of which a copy is filed for record should call for a bla;!ed tree, describing its markings, if such were used, a sapling squared, a post without tnound a poet Ti'ith rock mound, or a rock mound only, as the case I may be. Occasion alb' the notice of location calls for ''a monument of some kind, in apoeition which is iuao- cesaible and where none was actually set, so that when the deputy surveyor comes along and reports that he cantiot reach the point called for, there imme- diately arises a question oi veracity between the loca- tor and the deputy, which may seriously delay the proceedings sn the Ifind o£Eice. If the point where the luouumeiit should be set is inaccessible, the location

I7ty PROaPBCTINQ AND VALUING MINES.

notice should Bay so and give the reaBon for not aet- tiog the coruer Qnd if set as a witnee po8t to show thd direotiOD of the end line, the supposed distance to the corner should be written thereon. The absence of a post at any of the cornere, if aucb canuot be set, does not invalidnto a locatiob, if the fact be so stated, aa the law daes cot enk imposBihilitieB, but tbe atate- meut tliat a corner was set in an inaccessible place, when it was not so set, ib Bure to reault in trouble.

Posting Noticee. — Iq addition to fully deBcribing the inonutnents in the notice of loeatioD, ihy shouM be so marked as to indicate 'nbat position they occupy with reference to the claim, aa "north end center of Deadwood lode," **northwe8t corner of Deadwood lode" etc. ; but if a stone monument be used the notice may be folded up and placed between two iQnt BtoneB or in a tin can, with tb mouth downward to keep it dry. Such a tin can is also Tery useful even when a post ia used, as it can be tacked to tbe aame (pi. 15, fig. 5) in a aimilar manner and forms a Tery noticeable and conepicuouB object. If there ai-e trees near the monument, they should also be blazed and marked as witness trees.

The notice should distinctly atate the name of the atate, county and nqiuiny: district in which it is made, the name of tbe miner, the name of tbe adjacent claims if they are known, tbe date of diacoverj' the date of location, with witnesses if possible, and refer- ence should be made to prominent natural objects, 60 as to make the position of the claim ascertainable, if, after ail precautions hftve ben taken, thd nuonumenta should be accidentaUy destroyed, as by floods or snow slides. Such references may be, for instance, "on south side of Index Mountain," *'on the north side of Crab Creek, 2 miles above its junction with Pole Creek," "2 miles northeast of Minergville, " etc.

The exact wording of the notice of location ia of but tittle consequence, ao long as it givea the iuformation

Making Lovationh.

preTiously stated aa a location of lode olaim neces- earily carries with it all the dipa, spurB and angles, !tDd all tbie privileges granted by the vai'iouB acts of OongrGBB,withaiit a reaital of Buch claims. All that is requireil ia suoU a docniueut that no one can misun- derstand tbe intention of tbe locator. If this clearly done, tbe sborttir tbe notice tbe better.

It bns takeQ sotue time to describe tbe requisites of a first-class notice of location;, wbereaB it only takes a few minutes to write it out and secure the satisfaction which ftlwfi.vfl jijoea with a job well done but it ia not intended to imply that a notice not bo complete as iere sketched would be invalid. But very few con- tain every item in detail, yet the nearer it approaches to the correct tbiug tbe more safely can tbe prospector yave bis claim to the tender mercies of tbe elemeuta.

How TO Make a LocATinN. — Placer and Coal. — In tuaking a.louation of placer or coal ground on surveyed Jincl the location Dotice should, describe the ground yiy tbe usual legal subdivisiooa, and tbis will cousti- tute a valid descritition because it can be immediately Qled in the Uuited States laud office and become the t>est public notice obtainable; but if the placer claim Xn on unaurveyed laud, a mouumeut must be Bdt at very change iu tbe direction of tbe exterior bound- aries and tneutioued in the location notice. Coal lands can only be taken in legal subdivisions as platted the ordinary land eurveya, and cannot be pur- <2liaaed before survey of the township hne been made.

Z/odes. — In tbe case of lode claims it customary "fco set the ends of the lode line and the four cornerB of t.he claim, but there have been decisioiis by the gen- eral iand office in which, with only tbe end center stakes eatahlished, the locations were sustained. If hiB method be eiupluyed tbe diacovery stake, aa well Qa the monuments at the ends of the claim, should be most tborouKhly established, and all of tbem should :ciaiiiiy show that the locator claims a deuitely speci-

Its

PliOBPECTlIfG ANl

7m

ch eide of bis lode Hi

Such

fied diitunca on eacb eide ol Itia lode iiDe. iSucti ds* cieioua are baaed on tlie theory tbat tbe Hurface grouml ia gructed ouly to enable the miner to work his claim tu tbe best ntlTantngOj and on tbe further itleti tbat a person finding a lode will naturally follow tbe outt:riiii in tbe course of bia esaniination, aud must coQisequeDitly find aixy moDutneuta already erected on tbe vein, tbus gainiii knowledge of the olaixoB of any prior locatora. But tbis would not oocur if the loaator were followinj a lode parallel to one previously located aud say, therefrom, so tbat it ia very tuucb safer to establish all the corner luonumenta, thii method baTing the additional advantage of dtifiu- ing the direction of tbe end lines, wbJoh is left open to interpretation in tbe other case, unless it is plainly stated that they are to be at right augle,a to the lode line. The following remai'ka will therefore apply only to olaime having all corners established, except where thvy are evidently applicable to other locations aleO',

It may seem a very simple mutter to make a lode location alter finding ore — just meaaure oU 1500 ft. and set the eonier posts — but there are many poiuta to be considered, if we want to secure the full privi- leges granted by the naining lawa. Should there bo any mistake in tbe form or direction of tbe original location, and adjacent claims be taken either endwise or laterally before the mistake is diecoveredj it iviil be too iate to remedy the defect by a new locationi as, for instance ; if tbe direction of tbe 1 ode line as located does not follow the lode, which may be found to run diagonally across tbe location, and pass out of the side inbtead of the €.nd lines. In such a case tbe side lines bcoroe tbe end lines, making tbe location on the lode much shorter than if tbe lode ran lengthwise of tbe claim. To avoid such errors, ivbich may ruin an otherwise valuable mine, time euoujb should be tftkeu to ascertain tbe true direction of the vein before meflBurina off tbe location. After establishing the

%

r

t

Making Locations. 179

initial monument or discoTery stake on the ore body, and posting & notice of location thereoD, so that there can be no doubt as to what vein is intended to be located, the prospector is entitled to a reasonable time in which to perfect his location.

Very often the notice of location is posted at one end of the claim (see A, pi. 15, fig. 10) and calls for "1,500 ft. on this vein, beginning at the post on 'which this notice is posted," or similar language, when there is no vein in sight at that particular point, leaving the intention of the locator uncertain, or to be interpreted only by finding the monument at the other end of the location, and ascertaining what outcrop may fall on a line drawn between the two monuments, which ma,v or may not be the vein intended. As in pl. 15, fig. 11, if the notice be posted at either end of the lode line 1 or 2, a line connecting these points noay show the outcrop of ore to be say 150 ft. from the line, in which case, in strict compliance with the law, in final survey for patent, the line from 5 to 6 should be ran through the point 7, making the distance from 7 to the center of the outcrop not more than 300 ft. By establishing a discovery monument all doubt is ended.

Lode Line and Outcrop.— His not absolutely neces- sary that the location should be made in a straight line, but the lode line should follow the outcrop with reasonable accuracy. This is often a very crooked line if the vein has a fiat dip. If the vein is largely quartz and therefore generally harder than the sur- ronnding country rock, it will probably crop boldly and can be traced without difficulty. If softer than the inclosing rocks, it may only crop on the steep sides of ravines, and be covered on the gentler slopes by earth and debris, in which case it maybe necessary to dig a few cross trenches at short intervals apart, so as to disclose its course. (See Chap. IX., for method of tracing outcrop.) "When all other signs fail it will

180 Prospecting And Taluing Minss.

probably be found to ruD parallel to the eeneral direc- tion of other veina in the district, or else nearly at right BDgles thereto. In the Matter case it may proe to he ouly a Bpur of a larger vem, bb shoru od pi. 3, fi. 4, E. At auy rate a notice at the poiot of discov- ery will hold a claim for a few days, while the true poyitiujj of thfi ud Hues is being eetabliBlied, and Tvith ordiuary diligence and a little woodcraft the direction of the lode amy gatietaWy be deterniined with ft rea- eoiuible amount of accuracy if tbe principles govern- ing the outcrop of a vein have been maistered, and tbe vein is strong eiiougb to be woatb locating.

Ill CHseB wbere tbe vein does not crop distinctly for 1,500 ft., it will be good policy to make two locations, eatablisbing one of the end lines of each location tbrougb tbe discovery stake on tbe outcrop as in pi, 15, fig. df which leaves a portion of tbe cropping on each location,, A and B. Tbia plan bas tbe advantage also of lesaeuing the cbaDceof tbe rake of theorebody in depth carrying it beyond the end lines of tbeclaim oflfers a better chance to develop both locations through tlie same tunnel or shaft. Tbie plan is much preferable to the cointaon one (td. 15, fig- 10) of cov- ering all the oiitcro|> by the location A and making estension locations Ji mid C, in which no outcrop is visible, as tlie latter lucutiona are invalid until ore baa been found in them. lu tbe one case the locator has a good title to 3000 ft. in tbe other to only 1,500.

Length and Eirfrii.ioTis, — Haviiig dfiterEpined the direction of the loJe line, and the manner in which he "will make bis locations, the locator can mensure out any number of feet iu eithor direction for hia claim or olainiB, provided the total length of each one does not exceed tbe statutory limit of 1,500 ft., and tbe end mouuraents may bo established. From theaame point be can take one claim with Ray 500 ft, in one direction and IjOOO fL in the other, or two claims of 1,500 ft. each one in each direction from the discovery. If

lAKlNQ

only ong claim ia laid .off, it is good policy to be sure that the loaatioa is fully 1500 ft. lou; if a little more it will sot mutter, as on £nal survey tbe claim oau be cut down to its proper length if in 67tcesB, but it cannot be Idagtliened beyond tlie oriiginal at&kes, if tbey have beeu established too close together, and tbe claimaiit muy lose a portioti of ground to which be might hara been legally eDtitled. If on tbe other baud, a aeries of lacatioua are i:uade oo the same veiu, it will always be policy to make the locations a less than 1,500 ft, eaoU iu length (ualeaa measured with tbe accuracy of a final survey), so aa to avoid awkward gaps between them, aa will be seen must occur in such a series aa ahowq in pi. 15 fig. 6, where it is evident that tbe end lines of location A must be finally established at 1 and % If 2 has been taken ae one end of B, the other must be set 20 ft. short of the original poet at 3, or at 4. The ends of D can be set at 5 and 6, but if 5 be taken aa one end of C there will be a gap of GO ft. between 3 and 7, making a total of 80 ft, at this point to be relocated, and secured only by an expenditure of $500 for labor, in additiga to the coat of survey and land office proceedings. Under other circumstances the gap of 20 ft. may occur near 2 and GO ft. neard. It is better to make the looatiane safe from this defect by making each of them a trifie aUort and making an aJditioual one, if necessary to cover all the ground desired.

Even in the case of four claims of rather irregular length, but aggregating just G, 000 ft., all owned by tbe same corporation, the laud office would not permit the adjustment of the dividing end lines to make four even aurveya of 1,300 ft. each, but requires strict adherence to tbe original monuments.

Setting Comer Monuments, — In setting the corner moiumente, be sure that thtiy are, if anything, a little farther from the lode line than the distance called for in tbe notice of locatiouj as the distance allowed ou

1S2 Pbospbcting And Valuihq Mines.

final survey cannot be greater than tte poaition of the cumer moaumenta calls for] in other words the jQcnumeuts goyeru and not tbe words of the locatiou iiatice. No ground oaa be included iu the final sur vey for patent which lies outside straight lines con- necting the BQonumanta as they exiet on the gronnd, and the end lines mast be parallel.

Havinii taken the pre<;aution to keep the corner monuments far enough away from tlie lode line so the Anally eatablished side linea Eihall fall within, them, it ia next necessary to see that they are so loeatdd that the end lines can be drawn parallel to each other and yet pass through the ead monuments on the lode line. It is here that the deputy surveyor usually encounters the greatest difficulty. The aitua- tioii can beat be eiplaiaed by such a diagram as pL 15, fig, 7, iu which Z shows a defective Joeation, be- cause if AB repreaeuta the lode line, and C,D,E,F, the four corner mouumenta; the surveyor, to make the end linea parallel, must prolong EB toward aa in the dotted line, and then from G lay o£f a parallel Ijno toward D thus cuttiug the lode line short by the dis- tance A H. He cauuot draw the end line SS through A, because it would include ground outside tbe posts or mojiumanta, namely the triangles SfD,A and A', CA not included in the original location. In the same figure W ahows a weU-mude IticatioDj so far as the prospector's interests are Gancerned, as it is evident tliat the eud lines SS and 00 can he drawn through the lode line posts A and J", without shortening the length of the lode Hue, and can have a variety of di- rections given to them, while remaining parallel, a point of great importanCBj as will bo seeu shortly.

It follows almost inevitably that oue sattafaotory loca- tion must iu common practice necessitate an adjacent location in had shape, so that whatever may be said of the policy of making the lode line mouuments of one location comunon to its esteuBionSj the ordinary prac-

Making Louationb.

iioe of making the comer jDODumenta also comuiou to adjacent claiiua BhouLd be abaodoued by tboie wlio nvish to avoid trouble on linal survey. Independent poets should be BBtablialied as abown oq pi. 15, £g. 8. Iq this figui-e tbe corner uionuments of location A are marked aVa(2 while its corners of location B are numbered 6',i*,i/', and 6'-. The diagram eipjaina itself, being only two locationa Hbe If in lig. T, placed end to end. By adopting this syBtem, the parallel end lines can be located anywhere in the ground covered by the overlaiipjng cornere, as shown by the heavy rarallel cross lines.

End Litiea.—lhQ acts of Congress grant to the locator 1,500 linear feet on the Tein, and call for par- allel end lines, eo that a uniform length on the vein eball be maintained at all depths, aa the niinflrB follow the vein downward on its dip, the end lines being ex- tended downward vertically and prolonged indefinitely in the direction of the dip. If any other policy w-ere allowedj the ownership on the vein in depth would be a variable quantity, diminishing in length if the end lines of the cluim converged toward each other in the direction of the dip, and increasing if they diverged from each other, as can be seen by reference tp pL 15, fig. 12, which shows two locations on the lode a b, the dip being indicated by the arrow. The dotted lines show the non-parallel end lines prolonged in the direction of the dip, and it is plain that the looation C would constantly be gaining, while It would be losing ground in depth. For this' reason the end lines of a claim must be kept parallel injustice to both locators. It is not, however, always an easy matter to do thifi. the £rat locator usually s:etting in practice an advantage over b)s Jater located neighbor.

Surface Length and Actual Lode Lenyth. — "While the grant ay8 "1,500 ft. on the veinit is in reality 1,600 ft. on the line of the outcrop of the vein measured horizontally, and by varying the angle between the

184 Prospkotijq Aud Valuing Mines.

end Hues find the lode line, tlie locator may Hcquiro either leBB timn 1,500 ft. lueaaured horizontally od the real vein or a great deal more. Take for instance the case presented in ph 14, fig, 1, in ivhlch AB gboTve a locution of l,i500 ft. on the outcrop of the vein a tuonel on the vein etartiug oil the otitorop at A and terminating at 0, on the prolongation of the end Hue of the location DE, ivhich is made at right angles to the lode line. The dip of the -vein in the direction of the arrow is 60° from the horizontal, and the rise of the mountain side on which the outcrop is located from A to i? ia 600 ft. Fig. 2 Bhows a croBB section of the lode on the line CDE in fig. 1, and the dimen- Biona juBfc given make the horizontal distanoe from BB, which is vertically under the point B on the out- OTop on the end line, to the tunnel at G 287 ft (ignor- ing fractions). Keturning to %s.. the line AC or the actual distance owned b' the locator on the lode horizontally will therefore he longer thati Ihe length on the outcrop; viz., the scmare root of 1,500 squared plus 287 squared, or 1,527 ft. approsimafcely.

If the rise of the outcrop is 33, aa iB not infre- quent, the height of B above £ifor C witl be 817 ft. anil the dietanee BC 408.5 f i ; and AC will be 1,646.7 ft.

But if the dip of the vein be 45° and the slope of the outcrop ia 33, B will be 817 ft. above C; BC ill be 817 ft. lone. aadCl,708.2ft.,or208.2ffc. longer than the grant on the outcrop.

Hence it can readily be eeeu that the apparently un- important tiuestion of the position of the end lines is really one of great iHiportance to the owner, when the lode has a flat dip and crops on eteep hilleideS;, cut- ting a smaller and smaller figure as the country be- coioeB flatter or the lode more vertical. ' When per- fectly vertical both lines would be the same length; as also in a level plain. (PL 14, fig. 1, fa dieiorted to give better room for display,)

Making Locations.

When makiug a siiigle location on a vein, rect- nngular end lines may be nncloubbedly the best; but tbd rversa may be true ivhere a aeries of such looa- tiona are made, nnleag the outcrop of the vein follows a very airaight line, which is only the case when it is nearly Terticah If ginuotis or crooked, as in pL 14, fie. 3, where a,a'a"a"' is the outcrop and the orrow shows the dip, a single location like if will be satig- fftctory; but if we a.dd QnotIlLiei% as IV, at a latei' date, will take everything in depth between the dotted lines at) and a'b, while Ttwill only be able to follow the vein downward till it encountGis the line a'b, and Btors the shaded triangle between the lines a'b and a"c. If a third locatian be made as shown, no one will own the gore between the lines a"c and Q"e, nor oart title be acquired thereto, because there is no vacant ground on the outcrop at a" on which to bssea location. This h, of course, an extreme case, but if nil the lacatioDs ate made iu the interest of the same parties, it is evidently better that the end lines should bo made as in pi. 14, %. because the distance on a horizontal line between the end lines ab and hh would always remsin the same, at any depth ; whereas in fig. 3 the end lines ah and a"'h uonverge, and would ulti- mately intersect each other and cut out the ownership of the lode completely.

Puzzling Locations. — It may be well to call atten- tion to some other defective forma which result from a Teia with a dip, traversing a hilly country cut up with deep ravines, producing the result's discussed in tba subject of outcrops and illustrated in pL 9, - 3 and 5, and from the frequent want of a coutiuuoua oub- crop. If the ore cbutee are as shown in pi. 9, fig. T, the outcrops would he conspicuous on one side of the raviaea as at cc, but would be acaraely visible on the other, as at dd. In a plan these outcrops would be seen as at od in pi. 14, fig. 5, which shows two ravines with intervening hilis. For want of knowledge how to

1B6 PROSPEOTlIfG AND VALUING MINES.

trace a rem, a great number of locatioQS are iniide by cojitinuiug the Lidb of the vUible outcrop as in the lociations ZZ in a straight liue, but if the dotted lines show tbe couDectiDg portion of the vein, not exposed, it IB evident that it will paas out of the side lines of the locations at U). Tba complications which could arise fram suoh a oondition of thing)?, on workiQg tbe lodes, are almost endless, vairyinK aooordiue to tbe priority of looation aad the direotion of the dip of the vein.

Another form of trouble ariBiog from the aame causes i& shown in pi. 14, Jig. 6, in which Q.a are the outcrops of the same vein, on two sides of a ravine, tbe GOQQeotion between the two Dot being visible on account of accumulated debris in tb© stream bottom. Instead of two locatioas crogsiug each other, a ainglo location should have been made foUoTviug the solid linea but modifying the direotioD of the end lina as shown. Huch a location, while having 1,500 ft- on tbe outcrop, would have a shorter length on the veiDj but whatever this njight be, it woidd remain uniform.

In granite countriBB eapeuially, the ore bodies may be short, lying in the veio aomewhat as shown in rl- tig. 5, where the peculiniity ia exaggerated for illustration, and may present themaelyes as a series of short, more or leaa parallel outcrops, as in pi. li, £g, 7, aaa. These are often made the basis of a series of locations as XXX when the true line of the vein is shown by the dotted line, and two locations, as 2Z, might have covered the property at a saving of several hundred dollarB.

Chapter Xi. Patents To Mining Ground,

In the States and Territories whore the United States mining I&tv iu operative the acqiiiaitioQ of title in fee simple to laiueral laud ia somewhat more com- plicated than to agricultural janda 3a special Hurveye must be made in Eaost cases to aepRrate it fram the iatter except iu the case of coal and atone lauds* which are sold by subdivisions of the ordinBry land surveys; or in the case of placer ground where tbe govcTDmeut Burrays have already keen exttiuded over tbe placer are, in -wbich latter case the land can only be taken iu tbe usual legal subdiviaions except that tbe selec- tion can be made in as mull quttutitie as lO-aore tracts. Bui iu all cases of application for patent to mineral laud a full description by exterior boiindariee, or by legal aubdiviBionfl, nauBt be publiehed, ao as to allow an opportunity for agricultural claimants or others to couteet the application, if so inclined.

Except where special siirveye have to be made to segregate tbe mineral land from the surrounding agricultural area, the proceedinga originate in the United Statea land ofBce for tbe dietrict Id whiob tbe land may be situated; but wbere Burves's bave to be made they originate in the office of the United States surveyor-general for the State iu hich the locations lies. Tbus the United States surveyor-general deals only with those claims which require special surveys; and to these we wiU rst give attention, ad they iQclude the much larger proportion of mineral loco- tioua.

PnoSrEGTINQ ANB VALUING MINB8.

Before going furtLer it will be ell to note the dif- ference bolween a "location" gnd a "c]ainj,"aa tLe worda are often used iudiscrimiDatelyj, aHliongb In land uffioe pi'oceediiita tUey hate dietinet and very differ- ent Uieauioga. A lode location must not exueod 1,600 ft. in length by 600 ft. in Tvidtb ; and a plactr loca- tion must not contain inore than 20 acres, but may be uf au3' sbape necessary to cover the ground Bouglit to be purchased. Ou the other hand a claim may include as many locutions as tbe owner or claimant may bave been able to purcbaBe, pj'ovidcd tbey are adjacent to each other, aud a patent for a aiugle claim may con tain many locations. In auch a consolidated survey and patent tbe aggregate of aay eight placer locations must not exceed 160 aoreSj and no one of the individ- ual locatiotis must exceed 20 acres; if any of the loca- tions ftiU ghort of 20 acres, the lose cannot he made good by allowing an exceBs in some other location.

Procsdu7'e on all Lade Locafions, and such Placer Lonaiions as Lie on Unsurveyed Land. — In these matters a uniform process must be gone through and a rigid adherence to tbe routine of the Hurveyor- general's ofQue, as well as that of the local land ofSce. will greatly facilitate proigreBs.

Duties of the Surm-yor.' — All mineral surveys in- tended to form the basis of an application for a United States pfltent must be made by a deputy mineral sur- veyor. These deputies are appointed by the United States surveyor-general for tbe State, and are placed under bonds for $10,000, with two sureties, qualifying in double the amount, for the faithful performance of tbsir duties, '(V'hicb are carefully defined in tbe gov- ernment iuBtructions, and from which there can be no djvifttion without the risk of Berious trouble both to the suj'veyor and tbe applicant.

Ditdy Burvei/or's Fees. — The deputy ie paid for bis servicee by the aipUcaut, who bae the right to aeleot whomever he may prefer, and the compensatioa

Patents To Minino Qeouni>. 18D

for the work is a matter of agraement betweoD the applicant and the deputy, as there is tjo recognized scale of fees; suoh an arrangement being impoBsiblB on account of the widely different condifciana under which the survey a are made to accee&ibiUty of the locality, roughnesa of the ground and number of sur- veya to be made in any one locality. It ia evident that the incidental traveling exponaes 'will be just aa grub for the Burvey of one location aa for ten, if they ai-e in the eame vicinity.

The following; es.tract3 from tbo inetructioua JgBued to the deputy mineral eurveyora by the surveyor- general for the State of Washington will show the limit of their antihority and furnieh a guide to applieantB for survey in preparing their case :

Fiid Work (T).— The mirvay madi' imd reparrd nniat, fn every care, be nn Bctua] fliirrey of the Rnjund id full delalL rnod'; by ytM in jMr-son afS'-r rJiu receipt of the nrdKr, and vrtthoiit referent* to any knowladgB you lOHy liave pravioiialy acquired by rsasoa of liariniK naade the IsvntioD, euney or oIIjet- wisfl, and must show he hciusI FantH ftxlHting; at. the time, If the Boason of tlie year, or nay other cause, render aucli personal fsamimitinti imptBigibJe, you will poHtpotiB the eurvwy and under no cf'tiumntances rely upon tlie statements or surveya of uttuT partis. Or Upon a former eKOtniHation hy yonrseif-

Tlietenn*'3iirrpy" Iq fheseinstructfons&liSpHefl rtotoaly to th#r uiual SeW work, but al: to tne exaTninations required in the prHparitJnii of 3'our affl- davite of JSOO expenditure, deaurijitivo fesjOi'tS ou plucef claims, and all other r*poT(a.

d] Nq rttirn by yoi] will be rt'i!:oixed ad Dfncidl tmles9 uiaddliLpiirsuB.Q of a Hpecia) oniar from thin office.

jVrjf to Act as Atturney (6).— You are pi''lid'i from aoMii elthc'r dlren'tly or fndirectJy as attorney In mirLoml claims. Your duty in iLcy particulfir CiBsa ceases when yon have executed the murrey aud reti2m-d the Retd notes Uid preliminary plat with yonr report to tli"- siirveyitr i;enflml. You will not be allowpij toprejiare for the mintnKclainiiiTitthe papers in support of his applicatioD for patunt. or othviTwif perform t\w duties of an attorney befom the land office in connection with aminQralcUiiiD. Yuuftrc not prynitlxid to cjimhiDti the duiieR of diirceyor anil notary jiiiblk* in ihe same case by ad- tniniBtoring ofiths ti paritPB iuEerct. 1p eiort, yoii must have Bbsofutely nolhtni; to do with tlio case eKt'ept in your inlflciiiJ capai-ity aa Burveyor. You. 'will makf liO eurvey uf u iiiJDCi'Ii.l cyilni Ju whih yon lioldu ictert.

Survey nnd Lflco/iVrtifSl—Tho survey must bo mad" ia strict. CDnfo]'inity viXhy or lie Hiiihp5K!ii within thf- of thf; i-pporderl l™yitioa njion tbB ordi?r ia based . If thi- surrey and liMiaiiouar i(K"ri[ical, tlint facd muBt beclAflv and die tine tly stateiij In yoisr iltld iiutes. If not, idciitlial. a tar- InjC and dietanc must ba vmn from encJi established come- of thf; Burvey to the oorreapondlnfj eoracp af the lojation. Tho lint-a of tUa location as found upon the BTOUTnl, must, bfi IeUi] down upon rhe preliminary plat in mich a mannor as to contrnst and show their lelfition to the lines of the Gurrey.

(11) In aitordaU'tre with tlie pr1ijcl;ile tJiat courKW iiud dSnliinres iiinnE vb m,j wtieD in conflict with 6km objects awd tnouLments, you will Dut, under any drciuaBtanceft, change the comers of the Location Cor the purpte of

100 phospegting and vALumQ mines.

lUttkinKilTipni cOftfonn to tJne dwription Iti the r>ord. If the dlffereiice Irwii location Iw Blight, it mny Ijp sscpJainEHl in UjefisIdtiDtas.out If there Bhti'iild be a wide dit-rt'jiiiucy. you n'iU ipurt. the facts to ihia oPBce (UHl au'ulL further iniitrii<?tirnia-

From the foregoing it will ba seen how important it iH that eTer.A'tliine should be in good order on the grouuii before tho surveyor is sent on to it. There ia a widely prevaloiit idea tUat the eurveyor cau rectify any irreguluritles which he may discover, and reestab- liah corners which may be missing, without any prob- ability of futuro trouble, but this ie not the case. It is true he can take testimony to ascertain the former iroaition of missing corners, but this inTolvea delay and yitra eirTisB ft>r which, in the very large majority of cases, the applicants are unwilling to pay; and as the entire theory of the mining lawa ia based on the sup- position that a party plaoos no value on a neglected article the applicant should not be surprised if the authorities who have to pass on the legality of bis loca- tion take that view, and make no excuses for thiuga which ought to have been, and might have been, in better aiiape.

The duty of the auiveyor ie simply to report the facts aa ho dnits tbeiQ OQ the ground; if a stake or monument is misaing he must so state, giving such reasons as may apparently account for ita absence,, at the same time leaving the examining authorities to judge whether suoh reasons are eatisfactoryj if the monument ia in existence he must so report, and if not identical with the corner of a survey he must ex- plFkin why it is not; he cannot increase the length of a claim if it has been made Jesa than 1,500ft. originally; and ho must make the end lines parallel, though the side lines need not neceaaariiy be so. In fact he is not llowed to be in any aenee a judge of the equities of the case; he ia simply employed to collect the in- formation by which others can adjusti them.

Duties of the Applicant, — The following extract is from the official instructions;

PATENTS TO MIXflNG GROUND.

(I) . . . Tou are thensf'Ore ladviaed. before (IIlq jaar applicatJoQ, to eeo tlikt your tocatLou tiaa made In compliance wHh law and rfjulntlonB, U]d Cbat it pfeprly deecribcs ihe claim for wliJcb )jatent la sought.'

Office Charges. — There are certain charges for work in the officse of the Hurveyar-geuenil which are indepen- of the contract with the surveyor, and are intended to covr the coBt of examiuiog the led notes of the survey snd the preparation in quadruplicate of the mapB and field-notes, oue copy of which Ib Bent to "Washington to the general land oflBce, two to the ap- plicant, and the other ib retained on file in the ofiSice of the local surveyor-general.

(S) with regard to the plattio oC the clelm and DtTier office work in ths BUrrayor-Ben oral's ofllce, that oiTJiier will make ao estJmA.te of thk ijoat thereof, which amount tho clafraant will deposit with any assistant United States treasureT, or disignat-d dojJOiiiLoi, in faeor of the Utiitfid Si:ttt treafiurer, to be pniiiitftJ Vi the crKdit of the f iiart created ity indirldunl depna- tora for Biim'j's I'll' the public land a, and file with the GurToyor-g&nepal the duplicate eertiilcnt ot auch dejKialt in the usual maaiier.

C) ThB fijllowjn is the iRKtiniatd cost of platting and other offloe iropk in coDDectiou with tiie survey ot ULiuenU clahiis

Lode claim fat W

Placer claim SS 09

Mill sitfl clfliiii BS on

Mill Kite included one survey with a lodecLelm SS (X!

Each loUalaim Included in thestirT4*y ef a placer claim 25 00

BQTerallode or pi ncer claims iu onefiur\'ey, each iocatioa 35 OO

DeaciiptiTH report un placer elaim taken hy iegal eubdiviaionR, 10 00

(7) fihould t.he ottiee work. In any ease. aTuount. to ifiOPe than the RJjOwe otitaate. an additional deposit will Im reLpili-ed.

(H> In districts where there iftno Unitfld States depoeitopy. you'should de- poett with the nercittt JiSMLHtini Uuited States tTeiLiirer, or depository, aad In cases iniiriEriifttely firwanl tin? original i?eniflcate iof liepoeit) to tha Becrtftary of treasury (at Wui'hJtiKtuii, D. Q.) and the dupliuatt t'l tha Uj-veyor-gnt?ral, reia-ininE tint? trjpljci>1<* tor your owia uBc and Becurity. Under no c ire ums tail ces vill the ds'posit be made with the eurveyor-neral. Thti dpptriiK tut a((\i2 wurk Birri Hot tp maild quLjl the appucationa for survey are nsceived. and the parties notiflod by Lha aurveyor-generaL

The order of procedure is therefore aa follows : 1. Application Ulan'S. — As applications for survey must be made on the hlank forma adopted by the aur- veyor-general'fl ofifioe the applicBnt, uoIgbb Lg can secure one from the deputy surveyor should write to tbe survey or -general for a blank form.

ParticulaTB. — This application contains the name of the deputy who has heeo eeleoted to make the surTey,

Tilts ia tJip scale iflsned by the State of Waehlhgtoa, and ia only given Ic cciarey q general idea of cwt.

11)2 Prospecting And Valuing Mines.

and a requeet for an eBtimate of the oiEc© fees. It should also be filled out with the name of the claimant in full, as it is desired to appear in the application to the laud office for patent; the name of the mining claim in full, stating whether it is a lode or placer claim; the name of the nnnug diBtrict, and the land office district in -which the cJftim is located, and if the claim id made up of geYeral locations, they should all be euunieratod in detail.

With this application, there must be forwarded copy of the record of location of the claim, properly certified by the recorder having chiirge of th© records of the mill in fi locations in the county where the claim is situated.'* This may be either the recorder of the mining; diftrict, if one has been regularly organized, or the county recorder if no district has been formed, or the organization has been abandoned or fallen into disuse. "When securing this certified copy of the notice of location a second one should be secured and delivered to the deputy who is to mnke the aurtey, as he has to make the sarvey in conformity with the notice and return it to the survey or-general as a por- tion of his field-notes. The deputy baa also to file Tvith his returns a copy of the laws of the mining dis- trict, if such be organized, and it is important that tha location should conform to these laws and regula- tions. A local miuera' organization may impose any conditions they see fit on a locator, provided they do not conflict with the general mining laws of the United Stntes, and as lon as such local rules are in force in, a district, any application which takes an amount in oe3Gi of the local regulations is liable to be returned fur correction.

2, Deposit; Heceipf; Order for 5rue(/,— "When ap- plication for Burvey has been filed with the 'surveyor- general, he will notify tLe applicant of the cost of the office work, and this Bum must be deposited as previ- ously explained. On the receipt of the duplicate

Fatentb To Mining Ground,

receipt, showing that the charges have been depoaited to his credit the survayor-geiierEil iaeuea his order of Burvey to the deputy iLiiner&l surveyor, who can make no ofiSctal move until he is in receipt of this authoriz- ation. The applicant haa notbiug further ty do until the survey ib completed, and baa been examined and platted by the proper uuthoritieB.

Ab the surveyor has to niakB with has returhe a atutenieut of the Talue of the work done on the loca- tion, suiiported l\v the afGilavife of two digintereHted persons, the apjilicanta ahould be careful that fully $500 h!i.8 be*n expended iq actual mining jjuprove- znentHf as if thia has jiot been dose;, the papers are likely to be rfeturned, involving loss of time and es- penae. Tlie comraoji notion that 85 ahould be allowed for each dny'a work on the location is erroneous; labor should be counted at ita current rate, ivhatever it may be, aud to estimate a man's labor afe $5 per diens for the purpose of securing patent to tbe ground and only at @2 per diem for other purposes auggesta a fraudulent intent, and may lead to trouble, aa it is not carrying out either the letter or the spirit of the law. It is evident that if the location ia worth patenting at it is worth honest returns ns to the value of the improTement, by which is meant the actual amount of money spent upon the ground in which estimate trareUng expenses and auch other items are not allowed.

3, Publication, — "When the returns of the surveyor have been esaraiued and approved by the surveyor- general, he forwards to the applioant two copies of the field-notea and two copies of the ofGcial plat. The applicant muat then moke an agreement with the nearest loaal newspaper for the publication of the notice of intention to apply for a patent* wbioh notice must Qoutain such a description of the ground made up &om the field-notea sent by the surveyor-general, as will fully identify the ground and give notice to all adjacent

194 riiOSPECTINQ AND VALUING MmS3.

ownerB and ofcherB of what ground is alaimed. This notice must be pubUHhed 60 da.vs, or if iu a weekly paper it must appear in nioe consecuti've issues, "When this publication \s, decided on the applicant mUBt post one copy of the map and 6eld-notea upou the claim, in some conspicuous placS;, in the presence of two wltnessea, who must be disiDtereetecI parties, and thiB* notice must remain on the ground during the entire period of publication.

During this period of publication, any one has tbe right to iile an adveise claim to the ground, but if Buob claim is not Bled during this period the adverse claimant is debarred from further proceedings. Such adverse claim Then filed must be aacompanied with a plat of the ground showing the confiiet of intere&t, for the inforuiittion of tbe prior claimant and suit toust be commenced within 30 days in the proper court, to determine the respeotiye rights of the parties, and BUch suit must be prosecuted with diligence to a termi- nation. Evident negligence to do thie juatifes the land office in taking Btepa to force it, or dismiea the adverse oUJm,

Documents to he Filed; Final Pr'mf. — If there be no adverse claim tiled, the applicant is then ready to proceed witli his final proof before tbe United States land olhfie for the district in which the claim is eitu- sted, and will be required to file the following paiiers in tbe case :

I. ApplicHtioD Tur pat-ect. do th? usual blank forma, which must be in tha name ai the party at parties, sr iucoiiporfttioji, taaldue tlie ftpplicadon for fiurvB?.

2. l%e copy of the Burv'yor-eenriral's Offldai plat, with the ftOCOJnpanytng Qeld HotE.

A. A complete abtitracb iif title, properly" certifli by the proper Authorl- ttefl.

4. AffldiiTitof citiseTishlp, or in thd casn of an incorpoHitedl ".Odpany, of such iDLrurporiitiuu, no [latful cari fasiie to an aWtm.

5. Affidavit by two dlsiiitereswd parti?s >if the poaringf on the ground t>f tbo notice to njiply for patent, glvloj date of porting and locality aX, wtaicb it was post Oil.

fi. AlUilavJt tiv two ilisiDterested parties that Kucb dociDneuta remained CDntlnuously potert riiirintr the entire period of the pubUcation of the notice to apply for pntDt in the n'wapaper.

T. Agreemuat with tlie puhltaher aa to cost.

Patents To Mining Obovni).

9. A copy of tlie notice of public at Ion, mit from the paper, 9. Afflcfavit of the publisher tliQt |5ach cotit'e wns publlBhwl the Tequietta number of times, v\uji; the dates, auuic of paper, acid place of publication.

10 CenJOcata oi thw i'li'rk uf ifcip Superior Court that ritere lb no suit pend- inp ikfitcctiii ibe OwDtrhip of a. title to die ground.

il, iffldavIS qf two dlsiuteresced parties as to the value of the work done oud itsch&ractdi'. (TLose muat be s/ctuol mining ImprovemecLts. Houses, rofrda and trails are not cotisldtsMwl nt-cfcsarily uiiaice worlSs, anleaa ttey&rt connected with tunnsis. aliafts, or urhtir iniuiDi exuavB.tioiis}.

ja Affidavit by tliw applicant of Une costs vrhich )ifl,ve been incurred id securing the pateut, liL4;]udiiig such Itsms as nioni>:9 paid the surveyor, put>- liller,, attomcy, et.<;. (TtiR Olfjest of thiw i-s twi:>f<jt] : (Ij To protect the ap-

Sliciuit HBJnst axnrbitant charges; and iH) to protect Ui ovBrniuBut hy lueloiilijf; whetLiT prices litive paid whlcfi luigtit be tcfeiTsd to liave influi'uceo jutlsnipTiL uf the person receiving them. 13, AppUcatfiim t,a pui'Oha,

Fftymeut need not he made on the day on "wliich th "final proofs* is made in tte land office, by the pres- entation and approval of all the papers in th case but good policy involves prompt attention to tliiSj as tbe payment of the money due the government is ac- knowledeed hy the ksnatsce of a "duplicate i-eoeipt'* 'which stands in the place of a patent, and answers every purpose of a doounaent, until the patent ia issued, which is a matter of routine in Washington and may not be reached for a year.

Government Land Prices. — The price for lode loca- tions and mill sites is $5 per acre; for placer ground 92.50 per acre; and for coal lands $'20 per acre.

ConteHh, — The foregoing prooeedings in tbe land ofiBce are practically applicable to all mineral lands, and apply to all simple uncontested cases. The United States land ofGce ia also the referee where there may be a difference of opinion as to the character of the land, as between mineral and agricultural claimants} the contestants presenting their individual views by tenti- ruony, but all questions of ownership are decided by the courts. These may include priority of location, overlapping of locations, intersecting or cross vaina and 80 many other contiDgencies that in all cases of <onfliot the seirvices of an attorney ronet be called id. This chapter is intended only as a guide in those oaaea where all is plain sailing. In all others a good epeoial land lawyer should be consulted.

196 PSOSPSCTUfa AND VALUmG MINES,

Further InslTuctions. — The following itracta from tbe circulars issued for tb guidance of deputy Eut- veyora may be of intereet:

IS, The order of approve] of sujTej of tnloetftl cUttas b presclibed by Eeneral lacd office circular, datpcl March 3, IflSl, as followa:

"The rultiiu Bijrv*>y flrai applied for EflidJI have pripflty of tictlOQ it> all its rta;t% ill the uf tlii; surveyor-penfial, uii:liidj]]); tne delivery thereof, oviei" ftny other Furvpy of t-he same j?round or any ponian thersur"

"When Ihc siirvwy first BuchtiriKrfl tiot r!?tTirni?d Trithln a. reasO'n&blA

Boriod, and the applicant for a ciDnfiietini? uurtey cintrea affidavit tlial he Ije- t[tr>eHlHtiitiUK retuons for hy belief),' tluitHiich first appUcant hea a.l>aii- doTed his purixia' of haTin a surrey tnade. or ie defurriuf; it Tor TeiaTloia purposfti, to V'lt. to postpone His subaequent applk-ant. the SLirreyor-geiieral aiban eiire ddHcc of ffiich chBTgea to Fucn first appicnnt, an<i calf upin him for im txpluiiatiou uudtr <xith ot the dolny. He !il)ull Alao require the deputy iDfucral surves'or to rrnUre h full stawmeut in writicR, esplanatory of the delay; and Jf the Riireyor-QerLLl aball condud'e that od aod siifScient njanoiiH f'lr suc'h di;!:!?' do not exist, he ehall authprlfj the applicant for the contlLctJri survey to procetxl with the &a.me; otherwiae, the order of pocetd tofT sli.il| not he i.-ha.'i,"

" Wlienever an applicant for a, surv shoJI have reaaoii guppoHS that a conflicting claiinant will alfto apply inr a survey for patent, he may give a tioticfi in writing to the aurveyor-ifcnerBl, particularly describing; saai cJaioa, atid file a icopy of the notice of location of Bucti ouflictFug clalca, la sucb case the aurvfjor-ffeiicral will unL orilur or auttiorixe any eurveyaf such conflicting ctaCni unttl the survey first applied for has been exoinlnfid. com- pleted, approved aod platted, and the plata tlQllvered."

IB. Your attention 3b dircfit.'d to . . paragraphs of general loud offlce drculiir datt-d Dreember 4, 1384, rlz :

''1. The iiphta ranted to locators under sectloa 23SQ. Revised Statuiee, arerestrii;leii to suth locations on veins, lodes orledgQ&as may be 'situated on the piidUs domain.'' In applicAtiona for lode clkiins wherBthe siirrBv conflicUi viil a prior vnliid loc3:e cJnim or entry, and the sn-ound In conflict la ejyluded. the applictint not. oaly has no rieht TO the cscludeii ground, but he lias u. J riRht tfl portion of auy vein orHode the top or apex of which iici within aucli iixcliided prround, liulesR hia Joeation was prior to Jilay 10, iSTH. His right to the lode claimed ttrmitiotiJs whert the lods, in its oiiwiird course or atnke iuteraeicta exterior boundAry of each excluded grouQCi aDd pai#9eswltliin Jt,"

L'. The end-line of hia survey ahould not, therefore, bs established bef OH'I sueh iTitirspctioR. tiBlefis it loiilil bfi necef gary so to 4o Top the ptnpoae oC incIiKtini? found held and claiuicd under a locatrns which wag mocifi upon

fiutilic Land iLuA vnM E.t the t.ime it was cuode. To Includ'e flucb gttiiand K-hich may pOHsibly include other lodes) tlia endOlue the survey may fee establisLed wuhiu the coDllictiuf]: surroy. but the liae laasz be so tun oat to extend any further into the L-oElUctiuc surrey than may tte aeceBgary to aaka each leod-lias' pB.raIlel to tlie otiier eud-Unak"

CHAPTEE Xn.

EARLY DETELOPaiENT OF MINES.

When fifitisfied from thorough examiDatiou of tlie surfaoe indicationa that a deposit of mineral is worthy of further exploration, the question ariBes as to what the character of these explorations shall be to ac€om- plieh the beat results in the shortest time and at the Iflaat expenge.

''Follow the Ore." — There is one rule from which there should b& do variatioiij whatever piau may be adopted, in all prelimioary works, and that is, to fol* low the ore wherever it may go, no matter how crooked the shape of the developments may be; as it is only by deterininiug the shape and olmrfloter of the deposit that later works can be laid out intelligently and eco- nomioally. Thin plan has also the advantage of to BOioe extent paying for the work of development; asj if the ore is rich enough to ship, it will furnish a cer- tain amount of cash to continue the work, while at the game time such shipments will attract the attention of mining men, and go far toward ©ffeating a sale if thifl 19 contemplated, or securing aid to proFjecute the work on a larger s<:ale, Even if the ore be too poor to ship the may yet be a valusbie asset, and the number of tons it contains will be evidence of the faith of the owners in their property, and will furnish a better evi- dence of the producing capacity of tha property tbao any series of mere measuroiuents.

Cros3-GUt Tujinels,- — How often thig rule is disre- garded maybe seeo by the frequent newspaper notices

193 PnoSPECrmG ANJ) VALUmfQ minss.

tb&t "eo-and-so bare started a tuniid to tap the Tein 200 ft. deeii/' or someother attractive figure, wben in all probability the deepest ho!e on the property may not be 10 ft. deep. Such schemes ai'e uBually based on the mistaken idea ao often heard repeated that the mine iviil "sbow up*' in depth. Deep cross-cut tun- nels are admiaeible for working purpoaea when the mine is proved to be worth the coat of driviiig tliein, but they aro uuad'visabJe at the beginning of opera' tiona, unleaa it is impoasible to approach the ore body id auy other way ; aud in such cases the surface show- ing muat be more than ordinarily good to juatify such a procedure. Such early works have two fatal defects : (1) A shaft must be sunk ultimately, counecttng the surface and tuouel to giye ventilation, and good policy would indicate the propriety of sinking the shaft first, and runniog the tuuuei afterward to meet it, if the showing in the shaft juBtified it; and (2) such a cross- cut tunnel through the roeka whioh inclose the vein may cut the vein where it it; barren or in a "pinch," and cauae the abandonment of the property; and at the best after mouths of work, it t&Wn ns the character of the ore and the thickness of the vein or deposit at the sintsle point where it is encountered, when we ought to be learning something daily for every' dollar ex- pended. The point where the vein is cut may be much poorer than the ore on either side at compar- atively short distances away, causing au underestitnate of the value of the property; or the ore encountered may beariclibuuch, giving exaggerated ideas of value ; or the ore may have thinned out and disappeared alto- gether, which fact would have been demonstrated much earlier in a ehaft. Such a tunnel, unleas fol- lowed up by explorations of the vein laterally, adds little to the value of a property which may be offered for Bale, because it does not prove continuous orefroin the surface to the depth at which it cuts the lode — it only renders it probable ; while the same money spent

Bablt Deyelofment Of Mines,

ID sinking on ths vein might have produced a market- able propoaitioQ, or provad the smalln&B of the ore 1>ody at tuucb less cost. A tuDuel to tap the 'veio 200

tft, deep, is not likely to be lees than 300 ft. long, jind when completed and without drifts, only exposes an area of the Bome 5 by 7 ft. in extent, while a ahaft 80 ft, deep and 220 ft. of drifts and crosB-cuta (300 ft, of work ia all) would demand the attention of anybody looking through a njiniug catnp with a view to purchase. Sinking even small shafts or inclines is of course rather more expensive than tunneling, ea- peciftUy if the mne is at all wet; an the other hand, it is quite possible that the ore followed down and takon out as sinking progresseB may make up the dif-

tference. Depth of Tunnel Connections. — Many erroneous eati- mattis are made of the depth at which a tunuc] of a eiven length will tap a vein, unless actual eurvey has been made instrument ally, the tendency being almost always to oYereetimato the depth. The best guide ia to note the condition of the surface. Lone rock slides and mining dumps usually stand at angles Tarying from 30° to 35°, which tigurea give reapet!- tively a rise or fall of from 58 to C7 ft,, or an averoio of about 63 ft. in 100. To get 200 ft. of depth in a distance of 200 ft., the angle will be 45'~'> a very steep climbt and this occurs only in \eTy pieoipitoua regions.

Tunnfh in Foot or Hanging rTaW.— Diaappoint- ment also results from moniug; the tunnel in the foot wall of the vein, because in addition to the distance necessary to reach a vertical shaft sunk on the out- crop, if such existed, there must be added the addi- tional distance caused by the lode dipping away from the mouth of the tunnel, which is often forgotten. Such tunnels, if they must be run in early develop- ment, should be nm iif possible iui the hanging wall, so as to take advantage of the vein approaching the tunnel on its dip in depth. .

200 PRQ8PBCTINQ AND YALUmQ MINES.

Drift TunneJst- — Two otbermetbods of early develop- ment are possible — one by sinkiug qq tbe ffsia, the other by tunneling, or rather drifting on it, starting: OD the autorop and foJlowing in on tbe lode. This laat method is by far the most satisfaotory, ftaitproves both length and depth, for if the ore is continuous in the tunnel and in the outcrop oTerhead, we are justi- fied in Goneidering that it is coutinuouB to tbe depth of the tunnel, ami below, if it shows in the floor of the drift, and the mine has then what is known as "re- serves," or ore proved and merely waiting extraction. This method of development also posBesses the advan- tage (which may often be an inducement to run tbe cross-cut tunnele just diacuaeed) of one man being able to work nlone, using alternately tbe pick or fiingle-hand drill and wheelbarrow; and upraiaea can be made from time to time to tbe surface with eaae, as the material mined falls of its own weight to the floor of the drift, and can be removed without ad- ditional labor. If timbering is to be done two men are almost essential, and it may not he advisable under any ciroumstanees to wort aloae in a tunnel in loose ground, on account of the riek of accidents, but it can be done in an emergency.

Siiitaiug on the Deposit. — There are, however, many oases where we cannot at once drift on the lode, as the desirable localities may be covered by heavy debris, and the exact location of tbe vein un ascertainable, and we must then resort to siukinig on the deposit. Here aflin we must follow the ore, whether it makea the shaft vertical or converta it into an incline. At first one man at the windlasa will do, and two neo can manage for a depth of 80 to 100 ft. When this depth ia attained it may be profitable to drift on the lode toward daylitht, through the accumulated surface debris, and having reached daylight, to continue operationa by drifting on the vein ; or if it is desired to sink deeper, a horse whim will be able to hoiet from a depth of 200 ft> or somewhat more.

Early Development Of Minm.

InBinking by hand regard should be had to the size of the barrel or spindle of the windlasB on wbich the rope IB woufld, ae it requirea leas power to raise a heavy buotet slowly than rapidly. The aiae oi the spindle should therefore be emaller (say € in. ) for deep work than for shalloir pits, not only because a small spindle raises the bucket a shorter distance at each revolution of the crank and so relieves the strain, but because ita diameter is rapidly increased by the bind- ing; of the fope upon it, makiug the strain greater and greater as the load approaches the top.

fFoer',— The appearance of water in a shaft naay, hoTCever, modify all the conditions, and compel a resort to oroas'out tunnels, but if present in large quantities and arttSclal Jrainagie is possible, its pres- ence may be conBidei'ed a favorable indiicatioiij aa it is evidence that the liasure on which work ie being pros- ecuted is eiteuaive aad druina a large area, and may consequently aantain larger bodies. Such a condition is certainly more promising than a dry hole in 'vchich the ore shows little sijija of decomposition, or of the former circulation of water.

FosUion of Main Workwg Shajls. — TJaually from the nature of the esploratioua and the surroundiag physical cDnditiooa, especially where the mine must be worked on a large scale by deep shafts, tho loca- tion of such shafts in suitable relatiouHhip to the lude is a matter of much importance. When the dip of the vein or deposit ia comparatively flat we may be com- pelled to adopt an inclined in preference to a vertical shaft, unlfiisB it be so Aa.t that it can be worked like a ooal mine, on an almost horizoutal floor. But when the vein stands nearly vertloal the greater facilities for operating a vertical shaft may msiike such a plan desir- able. We must then remember that all mining ex- penaes increase with depth, and if dead work has to be done to reach the ore In the lola it is better to do such work near the surface, whil© expenses are low or

203 PROSPECTING AND TALUiNO MlNm.

moderate, than at greater depths wLere tliey are high and ooaatantly iuareasiny. Pi. 0, fig. 2, illustrates this, showLDg a vein and two shafts A and B, in cross eectiou across tLe lode. B is eTidently better located for economieal working than beoauae in the latter the length of the crosscuts from the shaft steadily IQ- creases with depth, while in B the longest croaacuts are near the surface, and, for the depth shown, the total amount of dead work ia much smaller than in, A, with inoreaaiug advantage for greater depth.

The same principle ia illustrated ijl pL fig- 4, aa regards the position of the shaft lengthwise of the vein, being the ore shoot with a decided rake to the left. (The rake usually diminishes with the in- crease of dip, being least in vertical lodes; and is usu- ally sitnilar in all the veins of a district having the aamo general strike and dip.) Here B located near the center of the outcrop would not be ia aa good a posi- tion as A, for the reasons just given.

Cross- Cutting, — In all eiplorotiona on the vein 1111- derground the importance of intelligent ei'osa-cutting ia obvious. No ore bodies are fitted into a clean-cut fissure with mathematical accuracy. The crushing of the rooks which make the forxaation of a mineral vein poasible ako bad a tendency to scatter the ore bodies when formedj and beoauae one body of ore gives out in a drift it by no meana follows that all the ore has given out in the mine. It may simply be shifted laterally to another plane of the "sheeting, The Keystone mine, Amador County, Cah, is croae-out to a width of several hundred feet with profit; and it does not even do to assume a perfectly Bmooth, oonttnuous root face to be either the foot or bringing wall, as a oass in Colorado shows, where such a wall was followed hy a drift for several hundred feet and when broken into under a change of management, proved to be only- one side of a more valuable body of ore than had beeii extracted by the drift.

Early Develops Eit Of Minr8. 203

Usually the diatancG to which the croas-cut may ba carried is indianted by the condition of the rook through \vbiuL it ia driven. As loug as tbie bUowb evident signs of decay or change, or tiacea of mineral, so long it ]iiay be desirable to continue the croBS-cut;, but it Bhould bo ntopped hb boou as the rock QBtumes the character of the main body of the wall roct.viaiblB on the surface, and not in contact with the vein. If working in limeatune where the ore occurs in pocketa ch&tnbei'tt the little striHgers of ore should receive egpectftl attention.

Syatetn in DevclopTii&nt.— In all these operations the watch word should be utility aud ecouomy. Unintel- ligent luanagcuieut may easily swamp au enterprise wbicii in proper hondij would have proved a success. Every bit of work doue ou a location should be the result of a caiefullj planned ecbeme, the portions of which will fit together "when completed. Especially should this be the ease with the annual flBSeastuent work. Too often the owner looks upon this work as a burden, and dusirea to do juat as smaU an amount of it as will lealliy hold the claim until he can sell it. Such ekiniped wurk will seldom sell a claim. Few realize that only by putting work on a njining loft- tion can it> in most inatancesji be made a aalible or valuable proposition; and in a hwe proportion of cases, for want of judgment, the work done leavea the property looking worse than if nothing had been done upon it.

Froitjiect Pits, — If only small sums of money are to be spent annually, these will be best expended in tracing the ore body by a series of shallow pits, rather tbaJi by starling short tunnels one after the other in places where work ia easy, only to leave them in barren ground. As at present espendad, most of the money ejjtnfc on asfiesBraeut work ia prac- tically thrown for want of system.

Juarge surface excavatiouBj except such as are neoea-

304 PmSPKVTIUfG AND TALtrmQ MINES.

sary to trace the ore, are pot deairoble, in or BDOWj' countries especially, aatbey only serve to divert the raio and buow iutotlieinine, from Tvhicli it may later on liave to be pumped at lieavy coat.

Vommon Tertns Used in J/i'jiiJif/.— Definitions of a few of these may be in place Iiore : A **Bhaft" is a vertical opening, tjithor on or alongside of the vein if that is vertical, or outskls of it (preferably in tbe hanging country) if the lode has & dip, but intersecting it in depth. An "incline*' is a eloping Bait, usually made to follmv the vein or ore bed. It may not he so eoD- venient as a vertical shaft for working, but involves less dead work in opening a mine. A "winze" in a shaft connecting the interior "workings, but Dot com- ing to daylight. It may be either vertical or an inolined winze. A "chute" (shoot) ig a winze suitably lined to paBs ore and waste from the workings to tbe oars on a lower level, ('*Chute" is aleo applied to a pitching ore body.) The drain tunnel, or lowest horizontal opening by which water can be diacbargod from the mine, is the "adit," **r)rifte"_or "levels" run from the shaft from time to time as it is deepened ; and are distinfcuishedfrom "tunnels," which have one nd open at the aurfaoe — the diftinotion between a tunnel and a drift being the same as between a abaft and a winze. The face of the drift is called tbe "bed"or "heading;" ground from which ore is being taken between the different levels is called a "etope/* Olid the ore may be removed either by digging down- ward, when tb6 process is called "vinderhand eto p*iug,"or by working upward, in which case the oporatiou is said to be "overhand" or "overhead." It is evident that by the latter method the material when broken down drops awsy from the workman more reatiily than by the former, and is usually the one em- ployed, unleae ctroumstancea absolutely prevent its economical adoption. The timbers which are put in keep tbe walls apart after the extraction of the ore.

EAULY DEVELQPMEJT OF MmES-

ao5

and also to form worklni Eooib for the mineiB, are called "Btulls/' and the hlliu done vith the waste material (in Corntvall "attle''), which is never taken from the miner possible to utilize it, is called the "gob." Wheu taken to the eurfaoa it forms the "waate dump." An excessively lare dump of waste material indicateBau excess of dead work in the mine; a email one on the other baud is by no means a bad tS&SLQ of prosperity. The bottom of shafts, inclines and winzes into wbieh the T?ater of the mine drains, and in which the pumps are locatedj is known as the '*8mop/* and is necessflrily below the lowest working levels its depth being gaged according to the amount of water to be removed daily.

CHAPTER Xm.

Ores.

DHFiNinona. — Ad '"ore/' strictly apeaking, isaBingle mineral \rbieh is a chemical caroponnd of a uaeful metal acd some other element or acid. In common usage, boweTei'j complex miitufee of pure luinerals are coDsiderBd ai: eingle ores; while ficee gold, native silver and native copper, together with their accom- panying gnagoe minerfllij, are alBo classed as ore. Among raiuer whatarer will pny to treat or ship and sell ia considered ore, as ulso low-grmle mineral which might be utilized by concentratiou or improved faeili- ties; but there is an iudeiiuite shnding off into mate- rial ooDtainiog tracee of ore minerala but hopeleaely unavailahle, and this is not considered ore; neither are gold gravel or platinum aanda called ore. To avoid miauTiderstaudin, it is beat to diatiiiguiab between t-he "ore" (meaning thereby tbe whole bulk of the available product) and the "ore mineral" (uenally very much emaller la quantity in all ores except those of iron, manganese, and some lead and zinc ores). la thiis connection will be mentioned only thoae minerals which produce the bulk of the usefol metals. Min- eralogiata describe some 850 different mineral species, of which a considerable proportion might posaibly bo called ores; but only a comparatively few are of pra(i- tioal importance — the remainder are of interest only to the collector and aciBntist. It ia believed tba'> thosa here described will be sufficient to enablo the

onss.

prospector to recognize nearly atl which are commer- cially Taluable.

The descriptionB are baaed on those in Dana's "Min- eralogy,*' and are auppoaed to apply to the minerala in their pnre crystallized forms, but such items as bardnees, woight, color ad streak aire common also to the maaBiTe forms. To make tbe desoriptiona ahorfe and compact a few terms and coatractions are em- ployed, which need e;£pUDBtia£] :

Adamantine reaembling a diamond.

Amorphous, not crystallized ; without any special form.

Arborescent, readmbliug the growth of the branches of a tree*

Boiryoidal, made up of masses of Taryiug size with smooth rounded surfaces, like grapes.

BriUiantj applied to surfaces which are perfect reflectora of litjht,

BrittlSf breaking easily.

Gompact, very close-graineil, not showing special crystals-

Conchoidal, as applied to surfaces of fracture, means resembling the inside of a clam shell in shape.

Concretionary f made up of particltse which have apparently growD together into a solid .

Ductile, capable of being drawn out into wire, or elongated*

Flat as applied to fracture, means smooth, like a board.

Fibrous, lite a bundle of threads laid side by side.

Filiform thread-like, not massed together as when fibrous.

Foliated, made up of thin leaves like a boot.

Oranutar, made up of distinct grains like coarse sandstone.

Iridescent exhibiting a play of changeable rainbow colors

Malleable, fattening under the hammer without breaking.

PUOSl'ECTINO AND YALUING MZSTES.

MammiUavi/ made up of many amaJl rounded but" j faces lite miniature breasta; uausily applied to forms of iucrusttiiioiis on rocks. J

Jila&fLce, not crystallized. I

Mefatlic, when descriptive of lu&ter, means reaem — -4 bling polished steel, silver or other metalB &a opposed to "earthy,"'

Micaceous, made up of thin plates, resembling flakas of mica.

Oolitic (o-o-litic), made up of rounded particlea, like fifth eggs.

Opaque, will not permit tlie paasage of light.

Fisoliiic, made up of rounded particlea lite peaa.

Beni/orm, kidney-shaped.

Resinous, resembling resin-

h'edtle oau be cut iviih a knife, like lead or ea&ier

Shining, opposed to "earthy/ wheu deseribiog the "etreak."

Sfaiaditic, resombling the cylindrical maBsea found hanging from the roof of limestone oaFee, formed hy dripping water-

Subcotichoidalf resembling coneboidal, but flatter, more like the inside of an o'ster sheU in form.

SubmelaUiCj with only a slight metallic luster, as a tarnished ailrer surface.

TranKh(ceiH, not perfectly clear, but resembling an egg when hald up before a strong light.

Transparenlj permitting the perfect passage of light, like glass.

Uneven, breaking into a rough face, like a broken briob.

VitreouSt glassy.

Waay, as applied to luster, not quite so bright as resinous, resembling the surface of clean beeswax,.

It would not be possible to give a good idea of the forruis assumed by the crystallized raiuerals without numerous ttiagrams, so that only occasional references are madia to crygtailifition. The physical properties

d

Ores,

used are the luster, color, atreak, bardaesa* weighty and manner of breakinj:. By the "strealc, " ia meant the color of the scratch made by a penknife or the color of the powdered miueraJ. The weight ia the specific gravity (in ratia to iveight of etiual bulk of water) indicated by the letter (r, and '\H an important item in all couceiitratii]{ operations or the aortiag of ores. The hardneB, iudioated by the letter H, refers to a Boale of bardnesa, in cominoD use, in which crys- tallized varieties of the minerals moutioued are meant: 1, talo; 2, gypsum; 3, oalcite or limespar; fluor- spar; 6„ apatite; 6, fiJapar; T, quartz; 8, topaz; 9, corundum; 10, diamond j so that if a mineral is anid to ha76 a hardness of 4 it would acratch 3, but would not Boratch 6.

QioiA>-'Natwe.—'E. 2.5—3. G. 15.6—19.5. Yel- low, malleable, BBctile. The depth of the yellow color Tariea with the amount of silver present in the metal, being deepest in the purest gold. When the value in silver beootnes equal to the value of the goldf the native alloy ia white. Distinguished from all minerals which it resembles hy flattening under the hammer instead of breaking. The minerals tor which it is moat frequently mistaken are iron and copper pyrites, but it may be distinguiahed from thefte, when in auoh a position that it cannot be tested by the knife or hammer, by turning the specimen completely round in the sunlight, when it will be found to maintain the same color and appearance xu every poaition. This is aot tbe case with the other minerals mentioned, which will alao float on the top of quicksilver, while gold will sink. Insoluble in Bimple acids. Distinguished from yellov mica by not splitting.

Teltarldes of Gold. — Theae minerals are not founci in large quantities, hut are assooiated with other ores, and from their want of resemblance to gold often puzzle the prospector who will get very large assays from samples which show no free gold. The four

VALumG- MINES.

Ckv

5

fortns may be distinguiehfldl by the following char- attf>i*e. Three of them greatly resemble lea<l, acd Boue of bhem are cojuiuon enough to have local names. Tbe iinportHiifc tellurules oavryiiig gold are:

Sylvanite.—H. 1.5—2. G. 7.9—8.3. Luster me OtG 15-7 tallio. Streak and oolor ateel-gray to silver-whit -X\. SSV BOmetimea braas-yellow. Fracture uneven. Approxi-

tniate composition: gold 30, silver 10, tellurium 60%, YL -s o.gyagile.—K. 1—1.5. G. G.S— 7.2. Luster me- tallic brilliaut. Streak and color Ijlackisli lead-gray. Opaque, SectUe- Compoaitlon: 6 to l'2% of gold Tith lead and fcellurLum. tX Hl Lgteej.gray and iron-black, aometimes tarniBhed Tvith 3? ''peacock tiots Streak iron-black. Brittle. Approxi- mate GompoBition : gold 25, silver 41,, tellurium 34%, Cdaterite. — Massive, Tvithout crystaHine etruoture; color bronEe-yellow ; streak yellowiab gray brittle. Practdre uueTeUt Aprroimate cotnpositioQ : gold 41, silver 3, and tellurium 56%.

SuvEs —Native.— H, 2.5—3. G. 10.6. Luster metallic. Color and streak Bilver-white. Ductile. Tflmishea easily to grayJah black. Malleable. Occura as wire silver, orystalliized (arborescent) or masgive, up to 800 lb, in weight.

Argentite, Siher Sulphide Vilreous Silver, or Silver Olance.—E.. 2—2.5. G. 7.2—7.4. Luster metallic,

k Streak and color blackish lead-gray; streak sbiuinf;

Opaque. Perfectly eeotile. Occurs eryBtallize<Q| amorphous, arborescent and filiform. Approximate composition; silver 85, sulphur 15%, Gives ailver when hesited on charcoal before the blowpipe. M

Pyrargyrite, Dark Ruby or Anliinotiiai Ruby Silver -H. 2—2.5. G. 5.8. Luster metallic. Color

Approxi eiWer 60, antimony 22, eulpliur

vU.-J blacky fiometimea approaching dark or purplish re

d. Translucent to oipac Powder purpliah red.

I 7 7 Streak cochineal-red. Translucent to opaque. Frao

ture ooucboidaL mate eoaipoeitioa :

Protistifef Light Bed or Arnemral Utihi/ Si'Iuer. — H- 2—2.5. G, 5.5, Luster atlamantiue. Color coolii- neal-rad. Streak cocliineul-red eacuetiines brighter. SubtraneiuceDt. Fracture coDchoidal, uueven. Pow- der bright red. Approiintiate composition; silver 65, arseuic 15, 8ulphur20%. Decomposed by nitric ncid.

Freiefilebcjiite or Gray Silver Ore* — H. 2 — 2.5. G. 6 — G.4, LiiHter raetulJic. Color aod streak light flteel-gray, inclining to eilver-wbite, also bluckiah lead-graj-. Tiekla easily to the knife, and is ratiiei" brittle. Fracture uneven. Powder Bteel-gray. Ap- proiimatfi composition; eilTer 22, lend 30, antimony 28, aulpijiir 18, iron and copper 2%.

SiephaaUe, Briitle or Blaet Siher.—'R. 2 — 2.5. G. 6.3. Luster metallic. Color, streak and powder iron-black. Fracture uneven. Approsiraate corapoei- tiou; silver 68.5, antimony 16, euiphur 16. Solu- ble m heated dilute nitric acid.

Cerargyrite, Horn Silver or Chloride of Silver.' — H. 1—1.5. G. 5.5. When nearly pure, looks like wax. Liieter resinouB. Color pearl-gray, grayish green, wbiti&h, rarely violet-blue, sometimes rolorless >vheii perfectly pure; brown, or violet-brown after exposure. Streak 'hiuiug, TranBlueent. Sectile, euts like wax. Not soluble iu nitric acid. A fragment placed on a strip of zinc, and moiatened with a drop of water, BWella up, turns bjiiok and finally is entirely reduced to metoUio silver, which shoTra the metallic luster on being prewaed with the point of a knife, Cooiposition : silver 75.3, chlorine 24.7%'.

Emboiife or Bromide of Silver,— "H. 1 — 1.5. G. 5.5. Reaembles horn silver. Luster resinous. Color usually greener than horn silver, often dark, beaom- iiig darker on expoaare. Composition: silver 67, chlorine 13, bromine 20%.

(Beeidee the above, there are some 20 other silver minerals of small importance oommerciaily.)

Fhi.rtsvii—Naiive.—H. 4—4.5. G. 16—19. Luater

-S

Is-

m

PmSPSCTUfG AND VALUING MINBB.

metallic, not very bright; color and streak ivhitish fittiej-gruy ; Rluning. Opnqne. Ductile. Malleable. OouuiB usually bhiqII grains; occasionally in maBses of eeverul ]<uuuJs weight. Infusible. Soluble only in heated nitro-njuriatic acid.

Ihidobmine— JVff/ifc.' — H. 6 — 7. G. 19 — 21. Lus- ter 'mstalJio. Color tiu-wbite and light steel-gray. Opflque- MaUenlile witU cliffictilty. Composition: the metala iriJium and o&niium in varyijjts propor- tions, io conibinsitioD Tvith small amounts of rhodium, platiuum &i3d ruthenium. Ocoura as small llattened grains in old vushinf;:a.

QmcKsiLVEK ohMeecuey — Native. "G,. 13.56. Fluid. Luster inetallic. Color tin-Tvhite. Opaque.

Cinnabar or Sulphide of Mercury. — H, 2, G, 9.0. Luster adamflntinej incliDing to metalHc when dart oolorecl, and to dull in friable varieties. Color cochi- neal-red to brownish red and lead-gray. Streak scarlet; gubtraDsparent to opaque. Fracture uneven. Powder bright iBcnrlct, being the article known as ver- milion. GompoBitton : quitiksilvsr 8C.2, sulphur 13.8%.

Mela/nnnahariie. — A dark to blackish variety of oinuabar. H. 2,5. 8.19, Luster metallic to dull. Color steel-gray or blaulii&h lead-gray. Streak nearly blauk. Opaque.

There are a uunjber of combinationa of mercury with seleoiumchloriue and iodine whieh are of small commeruial value.

CoPPEB."All the following minerala marked with an asterisk are disBolved in nitric acid, and wiU deposit red iiKitftHic copper on polifihed iron dipped into the sulutioiK

*NaUve,—B.. 2.5—3, G. 8.8i, Luster metallic. Color copper-red. Streak metallic and shining. Ductile und malleable.

*Ch(dro2}>/rile or Copper Pi/rite.JI. 3,5 — 4. G. 4.2. Luster jnetallic. Color brass-yellow subject tu

Ores.

m

"trnisli and ott&n iridleaoent. Streak greBDish blaok— ' little fihining. Opaque. Fracture conchoidal, un- >Tcn. Powder greenish-black. Varies m the inten- sity of the yellow color, when masflive, accordiiig to "fhe amount of iron pyrite in the ore beeojniDg paler s proportion. It may be distiDguiabed from iron ar>yrite also by being laucb softer and easily seratched -rith a knife. Composition when pure: copper 34jrH iron 30, sulpliiir 36%. V

*Oubamfef a Copper i'yriVp.-Sirnilartochalcopyrite. .U. 4.0. G. -4.0, CleaTage rather more distinct than in ordinary' pynte. Maflnive. Color between bronze Lnd brasig-yellow'. Streak dark reddish bronze to Tl&ok, Composition; copper 21, iron S9, sulphur 32% "with a little silica.

*Bnmhardite, a Copper Pyrite. — SiniUar to chalco- pyrite. H. 3.5. G. 4.5. Compact, massive. Luster metallic. Color bronze-yellow. Streak grayieh "black, slightly shining. Fracture oonchoidaJ, iineTen. Brittle. Tarnishes easily to peaaock tints, or becom- ing browB. Oomposition : copper 48, iron 22, sulpliiir 30%.

*Bornite, Purple Variegated, Horseflegh or Peacock Copper.— B. 3.0. G. 4.55.5. Massive, structure granular or compact. Luster metallic. Color bet'ween copper-red and pinchbeck-brown; tarnishes easily to red, blue and purple tints. Streak and powder pale grayisb black. Brittle. Easily scratched with a knife. Approximate composition: copper 58, iron 15 sulphur 27%.

*Chalcocite or Vitreous Copper. — H, 2.5 — 3,0, Gv| 5.6. Luster metallic. Golor streak and powder dark lead-gray ; often tarnishea blue or greeo. Streak fiotnetimea ahioing. Kesembles some silver ores, but gives copper instead of silver when heated on char- coal. Appro3;imate composition: copper 78, iron % Sulphur 20%.

*Tetrahedriie or Gray Copper,— H, 3,0— 4.6, G.

PRospEormo aid valuing minbs.

4. 5 — 5. 1, Lu Rter metnllic Color between ligtt flini-gray aud irou-bUck. Streak and powder geii- cfToXly the &u3Qai, sometimes Inclming to bruwu and okflrry-red. Opaque. Rather brittle, Fracture sub- ooDcboidal, uneven. This is a very oumplex ore, carrying not icfrequtiutiy a valuable amount of sliver- Ordinary coiopoaitiou: copper 30 to 40; antimony 15 to 25; sulphur 20 to 25% j with iron, araenio, zinc, silver, and sometimee mei'tiury. In forty-seven aualyaea given by Dana, the silver couteufca rany;e from a trace to 17%,, and in one iustanoo 31%, replacing copper or iron.

p. Cuprite or Bed Oxide of Copper. — H. 3.5 — 4.0- G. ill5.8 — 6.0. Luster adamautineor submetallic toeartlay. Color red of varioua ahadeSj, particularly cochineal- red; oocaaionally orimson red by traDBraitted light. Streak and powder several ehadea of browniBb red. Streak abining. Subtrausparent to subtraualucent. Brittle. Fracture aubconchoidal, nnoven. Compo- sition when pure: copper 88.8, oxygen 11.2%.

*jSIelacon.iic or Black Oxide of Copper.— M. 3,0. G. 6 — G.2. Ufiually massive or aa an earthy powder. Luster inetallic, and color eteel or iron-jray wLen iu' thin scales; dull and earthy, with a black or grayish black 'color, and ordinarily soiling the lingers when maBHive or powdery. Oompositiou: copper 79.85, oxygen 20.15%.

Malachite or Green Carbonate of Copper. — H. 3.5 —

1 Bi-ij 4. G, 3.7 — 4, Luster of crystals adamantine, iuclin-

.ing to vitreoup; of fibrous varieties, silky; often dull

and earthy. Color bright green. Streak paler green.

From translucent to opaque. Fracture subGouchoidal,

uneven. About fi2% copper; remainder carbonic

acid, osygeQ and water.

ytf.x. *Azurite or Blue Carbonate Copper, — H. 3.5 — 4.2.

XS.Q. 3,5 — 3,8. Crystallized or maasive, also dull and

,'i? earthy. Luster vitreoug. Color various shades of azure blue passing iuto dork blue Streak blue.

T9'

Oess..

S15

lighter than the color. Fracture conchoidal. Brittle, PurtiaUy traasliicent when crystallized. About 61% copper remainder corbouic acid, oxygen and water.

Chi-yaocoUd or Copper Silicate, — H. 2.0 — 4.0. G. 2.1. iSliightly crygtallice; often opal-like or enatuel- like in texture ; earthy. In seams or cruste. Some- times botr3'oidal. Luster Titreous. ahiningj earthy Color green, bluish green passing into eky and tur- uoiBe-blue; brown to black when impure. Streak T?heii pure, white, Traoiducent to opaque. Bather aeotile; translucent varieties brittle, Besembles the green carbonate but ie paler green usually baa a coarser texture (is nevet- Bbrous), a smoother suriacei somen'hat waisy luster, and is usually an incrustation Upon other ores. About 35% copper ; remainder elHea, oxygen, water and small amount of iron oxide. Atacamite or Chloride of Copper. — H. 3.0 — 3.5. G. 3. 7 — i.X Luster adamantine to vitreous. Color vari- ous sbfides of bright green,, rather darker than emerald sometimes blackish green. Streak apple-green. Sotnewbat translucent Composition: about h%% oopper; remainder oxygen, chlorine and water. *OfaJ c oi!i'fe , Sulphate of Oopper, Bluestone,- — H. 2.5-

Pd. 2. 2, Crystallized. Luster vitreous. Color shades of blue from sky to darker; sometimes greenish' blue. Streak uncolored. Taste metallic. Brittle. 8ub- I 'tiranslueeut. About 38% copper; remainder oxygen,

laulphuric acid and water. Soluble in water.

(In addition to the foregoing, there are of th xarer copper minerals some 21 oombinationa with sul- iphur and arsenic ', two with silica ; 26 with phosphoric, srseniouB or sulphuric acids; and two other carbon- ates. They are however, only mineral curiosities. The total number oi copper-bearing minerals is about

Lead — Noiive* — H. L5. G. 11.44 when pure. Lus- ter metallic. Color lead-gray. Malleable and ductile. Galenite, Galena or Lead Sulphide, — H. 2.5, G,

216 PROSPECTING AND VAimHTG MIKES.

7.2 — 7.7. Luster metallii. Color and streak lead- gray. Surface of crystals occasionally with bluish tarciflh. Fracture flat, subconchoidal or eTen. Very brittle. Soluble in nitric pcid, Tielda lead or char- coal. CrystallizBa in ciibea. Composition: lead 86.6, sulphur 13.4%. The chief ore of leadi usually carries Bome silTer, often aorae autimony.

Cerussile or Lead Carbonate.— H. 3.03.5. G, 5.4 '-G.l. Crystallized or earthy. Luster adamantine, inclining to vitreous or resinous; aometimBa pearly; aometimefi eubmetallic if the colore Rre dark or from superficial change. Color white, ijray, grfikvieh black, sometirae& tiijged blue or green by traces of copper. Streak uncolored. Fracture concboidAl; very brittle. Subtranslucent; usually opaque when masBiTe, Re- sults from the alteration of galena, which often fornix; the core of niasBive Tarieties. Composition : lead about 70%, remainder oxygen, carbonic acid and impurities.

Pyromorphite or Lead Phosphate. — H, 3.5 — 4.0. G. 6.5 — 7.1 ; "when containiog lime 50 — 6,B. Luster resinous. Color green, yellow and brown, of differ- ent shades; sometimes wax-yellow and fine orange- yellow ; also grayish white to milk-white. Streak white, sometimes yellowish. Sub translucent. Brit- tle. Fracture subconchoidal, uneven. Occurs only with other ores. Composition : very variable, con- taining phosphates of lead and lime, chloride of lead, £uoride of lime and arsenic.

Anglesite or Lead Sulphate,— "S. 2.75—3. G. 6.2. Luster highly adamantine, sometimes inclining to resinous and vitreous. Color white, tinged yellow, gray, green and sometimes blue. Streak uncolored. Tranaparent to opaque. Fracture conchoidal. Very brittle. Occurs massive, crystallised or stalactitio. Composition: lead, about 64%; remainder oxygen and Biulphuric acid. Easily fusible.

Massicot or Lead Oxide.— B.. 2.0. G. 8,0—9.0,

0Re3.

Xjusfcflr dull- Color between sulphur and orauge- yellov, Bometimea redtliah. Opaque. Massive or oarthy. Composition; lead 92.83, oxygen 7.17,

Minium or lied Oxide of Lead.— B.. 2.0—3.0. G. 4.6. Powdery. Luster dull or slightly greasy. Color bright red, raised witli yellow; streak orange- yellow. Opaque, Compoeition; lead 90,66, osygea 9.34%.

These oxides do not yield much cammercial lead but are given as they often occur as powdery matter in the ao-callad "chloride" orea of the minera.

(Besides the above there are some 40 non-commer- cial lead njiuerals. Id which lead ie combined with enlphur, antimouy, oblorio© and oxygen; or with ar- BeniouBj antimonioua, phoaphoriOj, tungstic, molybdic, fauadiC] sulphuric, chromic, seleDious and caibonio acids. Several of these, sunh as the molybdate of lead (wulfeuite) and the vanadate of lead, are beau- tiful waxy minerals of various ahadea of color from leraon-yellow to red, occurring usually in crystallizGd forma, making beautiful cabinet speoim&Eis but not otherwise specially valuable),

ZiNO — Smifhaonite, Deyhom or uic Carbonate,— K. 6.0. G. 4 — 4.4. Occurs orystallizad, reuiforui, botry- oidal or stalactitic aud as incrustatious; also granular and sometimes earthy and powdery. Luster vitreous, inclining to pearly. Color whStej often grayish, greenish, browQiah white, sometimes green and brown. Streak white. Brittle, Fracture uneven. Approxi- mate oomposition: zinc 52%, remainder oxygen and carbonic acid. TJaually carries saiall quantities of iead and iron.

Calamine or Zinc Silicate. — H. 4.5— E.O. G. 3.5. Oocurs crystallized, stalactitio, botryoidal and fibroua; also magsive and granular. Luster vitreous. Color white, aometimea with a delicate blueish or greenish shade j also yellowish to brown. Streak white. Fracture uneveu. Brittle. Containa 67.6% oxide of zino.

318 PROSPEOTINQ AND VALUING MmE3.

(TliG last two miaerala are very much alike in their geueral appoarauce, but Bmithgonite ib boluble in muriatio acid, wbUe oaiamiue fornjB a gelatioDUB mass unOer the eame oanditious, and is soluble iu strong CHUBtto potaiab.)

ZinaUe or Red Zitw Oxide.— B.. 4.04.5. G. 5.6. TJBually in foliated grains, or coarse pai-ticlea and mnaaes; also granular. Luster subadainAntine, Color oranee-yellow to deep red. Streak orange-yellow. Brittle. Fracture uneven. SubtraiiBluoent. Com- poaition: zino 80.26, oxygen 19.74%, usually contain- ing small quantitiea of manganeae.

BlendCf Zincblendef Zinc Sulphide or Blackyack, — H. 3.54.0. G. 3. 94. 2. Laeter reainoua to nilAinHDtiQe. Color brown, yellow, black, red, green; vuhite or yellow when pure. Streak wbite to reddisb brown. Powder nearly white, even in dark varieties. Fraoture conoboidaL Brittle. Tranalu oeu t to opaque. Crystallized or maa&ive. ConipOBitton : zinc 67, sulphur 33%. Distinctly ciearable.

FranHinite.—H. &.6— G.5. G. 5. GO. Crystallized and tuftssive, either granular or compact. Luster metalUc. Color iron-black. Streak dark reddish brown. Opaiue. Brittle. Fracture ooncboidal. Acta slightly on. tbe maguet. Soluble in muriatic acid. Approximate composition: zino oxide 18, laanganeBe oxide 16, iron oxide GG%, the proportioua of zinc and maiigaue,ti6 varying considerably.

Wiltemiie, a Zinc Silicate.— K. 6.5. G. 4.0. Crys- tallized maaive or in grains; sometimes fibrous. Luster resinous. Color whitish or greenish yellow wben purest; apple-green, flesh-red, grayish white, yellowish Brown; often dark brown wben impure. Streak uncolored. Transparent to opaque. Brittle. About 5S% zinc; remainder oxygen and silica. Car- lies small quantities of iron and manganese.

(Beaides the above there are some 15 other zino- bearing minerals of minor importance.)

Ihdn — Magnetite or Magnetic Iron Ore. — H. 5.6 — 6.5. G. 6.18. liUflter metallic to Bubmetallic. Color and Btrsak iron-biftck. Opaque. Fraoture auljcon- choidal, shining. Brittle, Strongly magnetic, BometimeB possBBsing pol&rit}', like the needle of a compass. Composition; iron 7*2.4, oxygen 27.6%.

Hematite or lied Oxide, of Iron, or Specular Iron Ore. ™H. 5.56.5. G. 4.2— 6.3. Cryatallized, oolum* nar granular, botryoidal and atalactitiCj as "well as micaceous and compact, Luater of crystals me- tallic, Bometinjes brilJiautiy so; sometimes earthy. Color dEirk steel-gray or iroD-black; wben earthy inclined to red. Streak cherry-red or reddish brown. Opaque. Fracture aubconeboidal, une-ven; Bome- times slaty. Sometimes attractable by the maEet. Gompoeition : irou 70 oxygen 30%. Variee ooneid- erably in its mode of ooourrence and outward appear- ance. When exceasively lustrous and brilliant it is known as "specular iron ore;" when in thiu flakea and foliated, "micaceous iron ore;" when compact or iibrouB with a reddish brown or iron-black color, "red hematite;" or "clay iron ore" when mixed with earthy impuritiea, and possessing an earthy fippear- &nce and no luBter, with not infrequently a deep dull red color.

Limonitet Brown Setnaiile or Bog Iron Ore. — 'H. B.O ' — 5. 5. G, 3. 6 — 4.0, Usu ally in Btalactitic and botryoidal furms having a more or leaa tibrons struc- ture; also concretionary, massive and occasionally earthy. Luster silky, often submetallio; eometimeB dqli and earthy. Color of surface of fracture various eLades of brown, commonly dark, and none bright; sometimes with a nearly black varuiah-like exterior; when earthy, brownish yellow to yellow ocher. Streak yellowish brown. Composition: differs from hematite in carrying about IG% of "vater. The term "bog" ore is applied to the modern formations found in marshy places, which usually confcvii manjanese as an impurity.

no PitOsSPEcrma and valuing mines.

(Ths three foregomg niliierala prndnce the l)ulk of tLe iroQ of commerce. Tbey can readily be diatin- guidhed from encb other by the Btreakt which is respBctiTely black, red or yeUoTfish brown. The foUuwiug minerals, while strictly irou ores, are valu- uble chiedy for their other constituents such as zine, chrome, suiiihur, aisenic, eto. and the precious metals found in thir company.)

Franl,iunte. — Described with the zino minerals.

Sid&rite, SpafhU' Iron or Iron Carbonate,— H, 3.5— 4.6. G. 3.6, Occurs crystallized; atso in botryoidal and globular forms, somewhat fibrous -within, occa- sionally silky. Often massiTe. Luster vitreous more or less penrly. Color aah-gray, greenish gray, alBO brown and reddish brown, rarely green ; sometimes white. Fraotiire nneTen. Brittle, Streak white. Composition : oxide of iron 62,1, carbonic uoid 37- Usually carries manganese magnesia and lime as impuritiea. A sparry looking ore, distinctly ole&table, turning brown to black on exposure, A good are of iron when abundant.

Pyrile, Iron Pyrite or Iron Sulphide — 6.0 — 6.5. G. 4.8— B. 2, Crystallized or massive. Luster metallic, splendent to glistening. Color a pale brass-yellow nearly uniform. Streak greenish or brownish black. Opaq.ue. Fracture conohoidal, iineven. Brittle. Strikes £re with steel. Composi- tion (omitting impuritiea): iron 46.7, sulphur 53,3%. Crystallizes in cubes. The pyrites of gold regions usually carry gold, which may be occasionally seen projecting from the faces of the crystals. Otber varieties carry small quantities of niokel cobalt, silyer or tin. Pyrite ia one of the commonest of minerals, and aside from the precious metals it contains, ia chiefly used in the manufacture of sulphuric acid, the acid being produced more cheaply by this methodl than from sulphur direct.

Marcas'i"-- — Similar to otditiary pyrite in compoai-

Orbb.

tion, but differs in the form of ibeorystals which are often flat and created. H. 6.0—6.5. G. 4.8. Crya= t&Uized, globular or reniform ; often mflssive or gran- ular. Luster metallic. Color palo bronze-yellow, sometimes iaclined to green or gray. Streak tjrayisli or brownish black. FrAoture uneven. Brittle. Often carries gold.

Pyrrhoiiie or Magnetic Iron Pyrite. — H. 3.5 — 4.5. G. -4.6. Commonly maBsive or granular. Luster metflUio. Color between bronze-yello-w and copper- red, and tarnishing eaaily. Streak dark grayish black. Brittle. Magnetic* being attracted in £ine powder by a magnet, when not affecting a magnetic needle. Thia ore is valuable cbieHy for the nickel it Gontaine, which in some cases ranges from 3 to 5%, and fiirnisbeB the bulk of the nickel of commerce. Composition: iron 60.5, sulphur 39.5%".

Mispichel or Arsenical Pttrites, — H, 5.5 — 6.0. G. CO — 6.4. Luster metEdlic. Color silvet-white, in- 3lJQipg to eteel-gray. Streak dark grayish blaok, Iracturo uneven. Brittle* Oompoeition : iron 34.4, Bulpbur 19.6, arsenic 46.0%. This mineral ia the source of the bulk of the arsenic of commerce, as well &n cobalt, and ia associated with and frequently carries silver and old in amall quantities.

llmenite or Titanic Iron. — H. 5.0 — 6,0. G. 4.5 — 5.0. Massive or as loose grains jn sand. Luster submetalHo, Color iron-black. Streak submetalilio, powder black to brownish red. Opaque. Fracture CDDchoidal. Slightly inHuencing the magnetic needle. CorapOBition: oxide of iron with varying amounts of titanium, 3 to 30%. Not a true iron ore.

(Besides the above there are nearly 40 other non- commercial iron minerals, Gonsisting; of ailicatea, buI- pbatee, phosphates, arsenates. carboQates, tc.)

Manoahese — Manganile. — H. 4.0. G, 4.3. Occurs oryatallized, atalactitic, seldom granular. Luster sub* metallic. Color dark ateel-gray to iron-black* Streak

232 PROSPBOTING AND YALUINQ MUfES,

and powder reddish brown, sometimes nearly black. Opaque. Fracture uneven, Compoaitioti: manganese 62.5, oxygen 27.3, water 10.2.

PyvolHUe, Matiganese Dioxide. — H. 2.0 — 2.5. G 4,8. Luster TQetaUic. Color iron-black, darJc gteel- gray, Bonietime bluisli. Streak bltick or bluLBh black, aometiinoa aubmetallic. Opaque- Bather brit- tle. CoiupoHition: maugaueae 63.3, oxygen 36.7%. One of the mot important ores of manganese; it is easily dietinguialied from psilomelane by its inferior bardness, and being usually crystalline; from man- gauite, by the color of the Etreak and powder. Often soils the baude.

Failomelane or Black Manganese Oxide. — H. 5,0—6.0. 3,7 — 4.7. Occurs maBsiTe and botryoidal* reniform and stalaetitio. Luster Bubmetallic. Oolor iron- black, pfiseing into dark steel-gray. Streak brownish black, abining. Opaque. Composition : an oxide of manganese (variabla in quantity) with oside of bar- ium, and several other impurities in minor quantities. Not being fouud crystallized the exact nature of the apeciea is yet doubtful.

Wad or Bog Manganese,— Ihe ores included under this name occur in amorphous and reniform masaea, either earthy or conipaot, and gotQetimea incruating. Tliey are misturea of different oxides aod cannot bo considered a distinct apecies. H. 0.5 — 6.0. G. 3.0 —4.2, often looaely aggregated and feeling very light to the hand. Color dull black, bluish or brownish black. Composition : manganese oxide, with iron, barium, cobalt and copper oiides in varying propor- tions.

(There are, in addition to the above, some 20ather unimportant mengane&e minerals.)

Tis— CasHerite or Ti.n Oxide.~n. 6.0—7.0. G. 6.4 — 7.1. Occurs crystallized and massive. Luster adamantine, and crystals usually aplendent. Brown or black; sometimes rod, gray, vrhite or yellow*

Ores..

£33

Streak white grayish, brownish. Crystals nearly- transparent, goraetimes opaque when masaive. Frao* ture Hubconchoidal, uneven. Brittle, CompOfiition : tin 78.67, oxygen "21,"%, Puniishes the tin of com- meroe. Doca not look much like a nietaUic ore and is often confounded with the valueless mineral epidote. Only slightly acted on by acids. I>eteoted usually by its weight.

Stream tin is nothing hut the ore in the state of and, aB it occurs in the gravel derived from the eoompeeition of the rocks carrying the ore.

Wood tin is aD irony-looking mineral a variety of cassiterite, very heavy, occurring in rounded, botr>'- oidal or reniform shares, concentric in Btructura, and radiated fibrous internally, although very compact, Trith the color brownish, and the rings of miixed shades looking somewhat Hke dry wood. Occurs in the gravel of streams.

StAmiilc or Tin Sulphide. — H. 4. G. 4.4. Com- monly maaBive, granulated, or dieeeininated through the rock in small grains. Luster metallic. Color steel-gray to iron-black, the former when pure. Streak blaakisb. When copper pyrite is present in the ore the color is often yellowish. Opaque. Brittle. Frac- ture uneven. ComipoBition: tin 27.2, copper 29. sulphur 29.6, iron 6,5, zino 7,6%. It frequently has the appearance of bronze or bell metal, and is henoe called "bell metal" ore.

(Tin ia fotmd in small quantities as a component of Beveral other ores.)

CnnoMiuM — Chromite or Chrome Iron. — H. 5.5. G. 4.4. Usually occurs massive; atructure fine gran- nlftT or compact. Luster aubmetallic. Streak brown, Oolor between iron-black and brownish black. Opaque. Brittle, Fracture uneven. Sometimes magnetic. Oompoaition : oside oE chromium 68, oxide of iron 32%'. Usually with alumina and silica as impurities when maseive. The ore has usually green luorusta-

234 FROSPBCTING AlffB VALUING MINES.

tioDfl in tfa flentuB which distinguish it readily &om the other irun ores. Affords the uhroioe of commerce iiut being imed as bd irou ore.

(Several other ores coutain efaromium, but not Id available (luuiititicH. )

NicERL — rtjrvhiihte or Magnetic Iron Pyrile. (Sea ii'OD orea). — The chief aotirce of Dickel.

NiccUilf, Copper-mcket or Arjuenicat Nickel.- Usually masfiive, ijo visible structure ; also reniform and arboresoent. H. 5.0 — 5.5. G, 7.5. Luster me- talliti. Color pale Goppur-red, vrith a firny to blackish toriiiU- btreak pale brownish . Opaque. Brittle. Composition : nickel 44.1 arenio 55.9; sotiietimeij part of the arsenic iereplaced by antimony, with eiflall i:iu(*iititie8 of lead, cobait and eulphur. Reaemblea pyrrhotite or magnetic iron pyrite, but is not inanetio.

OfTsdorJftie or Nickel Glance — C rystallizatios cubic; also lamellar and granular loasmve. H, 5,5. G. S.6 — (5.9. Luster metallic. Color siWer-wbite to steel -gray* often tarnish ed gray or grayish black. Streak grayish black. Fracture uneven. Composi- tiou : nickel 35.1, arsenic 45.5, sulphur X9A%f with part of the nickel often replaced with iron or cobalt. Out of IS analyses tbe nickel rnngeafrom 19 to 40%.

Gent/lite or Silicate of . — Not crystallized, occurring usually as incrustations. H. 3.4. G. 2.4. Luster resinous. Color pale apple-green or yellowieb. Streak greenish white. Trnnslucent to opaque. Au unimportant compound of nickel and eilioa, often associated with chrome iron.

Annahcrite or Nickel Ocher. — In slender crystals; also massive and diBBaminated through the gangue. Soft- Color fine apple-green. Streak greenish white. Fracture uneven or earthy. A compound of nickel and arsenic. Unimportant.

Zaratite or Emerald Nickel. — Incrusting, also mas- give and cuiDact. H. ..0 — 3.3. G. 2.6. Lustn':

Ores,

2Z5

vitteoua. Color emernld 'green. Streak palo green. TrHDalucnt. Brittle. A carbonate of nickel. Unim- pottftnL

(The last three minerals, with fleveral othere of Bimilar green color, include the greea miiierals found in niokel ores, and wliich UBually attract the attentiou of the prospector from their bright color, resembling Ihe green oarbonate of copper.)

Cobalt — Mi&pickel or Arsenical Pyriie. — (Desoribed mider iron ores).

iimaliiie Smaltine or Cobalt Arsenide. — Cryetallized Mid maaaive. H. 5.6—6.0. G. 6.i— 7.2. Luster metallia. Color tin-white, inclining when maeaive to Btod-groy, BonDetimejiridesfieut or taruiahed. Streak graj'ish black. Fracture granular and uneven.. Brittle. Composition: cobalt 9. i, nickel 9.5, iron and areeuic 12.1%. In some varieties the niakel is flbaeat and the cobalt runs up to 23% or over, replao- flg the niokel and part of the iron.

Gobaltile, Cobalt ine or Cobalt Glance, — Cry stall ized , TUBBBive, granular and compact. H. 5.5. G. 6.0— Luster metallic. Color eiWer- white, inclined to red; also steel-gray with a violet tinge, or grayish Uck when oantaining much iron. Streak grayish "lack. Fracture uneven and lamellar. Brittle. Com- position: cobalt 36.5, areenic 45.2. sulphur 19.3. lb cobalt is eonjBtimea largely rei>]ac6d by the iron, in which caae the peroentage may run down as low aa

Erythrite, Cobalt Bloom or Bed Cobalt — Crystal- lized, also in globular aud reniform shapes; also aa inoruBtations and powdery. H. 1.5 — 2.5. 2.9. IfUater pearly to Titreoua; also dull and earthy. Color crimson and peach-red, Bometimes pearl to gTflflniah gray; red tints incline to blue. Streak a little pater than the color; the dry powder deep Javender-bUe, Subtranalucent. Seutile. Composi- tion: oxide of cobalt 37.55, araeuic acid 33,13, and

22ti

pROSPwrma and val um& mines.

water 21.02 %. The (lelioate peaoli-rfid of this mio' eial ia very characteristic.

(The abave are the chief cobalt ores. There are a few others of lesa importanae. Cobalt ia a frequent associate in Diukel ores, and both nickel and cobalt ofteE occur iu copper orea.)

AjsTiMONT — Stihmie AntimOTtf/ Sulphide, Gray Anfi- mony or Antimony Giiftce.— Ocwure ory&tnlliaed or muB- sivB. "When masaive, uot infrequently more or leaa fibrous or radiated. H. 2.0. G. 4.5. Luster metal- lia. Color and Btreak Itsad-gray, iuclining to steol- gray ; liable to blackish tarnieh. Fracture small sub- conouoidal. Seotile. CompositioD : autitaony 71.6, sulphur 28,2%'. Rasembleaaome inangtftneee ores, but IB distinguished by beiug easily fusible, furnishes tbo bulk of the autinjony of commerce.

(Native antimouy and the osides do not occur in luantities to make them valuable as ores of theiiaetal. )

Arsesic — Eeahjar or Red Sulphide of Aritnic— - — Crystallized or grftnular and compact, H, 1.5 — 2,0.

G. 3.5, Lui5ter resinous. Ciilor aurora-red or or&nge

yfllloTv. Ktreak aiinilar. Translucent. Frapture uu

even. Coiuposition : araeni*? 70.1, sulphur 29.950-

Orpimentor Ydlom Sulphide of Aram ir, — Crystallized or raflHsiTe. H. 1.5. G. 3.5. Lunter jiearly on th faces of cleavage, elsewhere resinous. Color evera! shades of lemon-yellow. Streak s. little paler than tb color. SubtranBlncent. KJubsectile. Comx'UHitiou: ursenifi 61, suliihur 39%.

(The above ruinerala do not occur in lare quanti — ties. Artificially-made orpiment is used as a paint*'' Commercial arseuic is usually a by-prodnct from th working of mispickel and the oree of nickel- &th cobalt.)

Bismuth — iiTo/tue.— Cry&tallized, foliated or gran ular. H. 2.0. —2.6. G. 9.7. Luster metallic — Streak and color silver-white, with a reddish hue subject to tarnish. Opaque. Sectile. Brittle whe,

J

—

Ores.

ssr

k

cold, but aotnewht malleable when heated. "Vry fnaiMe.

(Biaiautb occurs in some dozen oombinations, but :tiBuallj' in gmall quautitiea wHli other oampoutidB in luiEersii teiUB. The uativQ metal furnishes the bulk of the coiuraeriiial article.)

TjTisiuM — Rutik or Titanium Oxide. — Crystallized orciaBBive, H. 6.0 — 6,5, <3t. 4.2, Luster metallic- adamautine. Color redJieh browrij pasHiug into led ; somfltimes yellowish, bluieh, violet, black; rarely "asa-reen. Streak palo broTvn. Subtrauspareut to opaLjue. Practure sufaconchoidal, uueven. Brittle. CouipusitioD ; tit&ninm 61, oxygen 39%,

(Iltiieuite titanic irun etc. are described with the irou ore. )

TcraaTEn— fFrjiTramiYe, Tung.'fcUe of . — Cryetal- lizedormasaive. H. 6.0— B.5. G. 7,1 — 7,5. Lusteraub-

iBtallic. Color dark grayish or brownish black.

treuk dark reddish brown to black. Opaque. Com- pysititm: tuugstic acid 76%, in combination with iron lid manganese in vftriable quantities.

(TLe tungstatee of lead and lime are of minor im- PW'tflnca.)

vADjiiuai — GreenocHte or Cadtnium Sulphide, — H, 3.0--3.5, G, 4.8. LuEter adaniaiitiue. Color honey-yellow, citron -yellow, orange-yellow, bronze- yelloiT. Streak and powder between orange-yellow briek'red. Nearly transparent. Composition ; cadruiiini 77.7, sulphur 22.3%.

MoLVBDEifOM — Molybdenite or Mohjhdemim Sulphide.

UsuaHy foliated, roaesive, or in gcalee; also fine graijuJar. H. 1 — 1 . 5, being easily impreestd by G. 4.4—4.8. Luster metallic. Color pure Streak eimilar to color, slightly inclined Opaque. Laminffi very flexible, but not Sectile, and almost malleable, Fine gray iiiark on paper. Composition: molybdenum 59, siil- pliur 1%. Resembles graphite, but is decomposed

nitric aoid.

tlie qmI. lead- pray Hlastio,

PMOSPMUl'ING AND VALUTNG Ml2fiB8,

Uraniitm — Uraninite Oxide of Uranium, PUch- bletide, — Usually tDaesive Rhd botryoidal; also in grflJQH. H. 5,5. G, 6.4 — Luater eubixietailic to greasy or pitchlite, aod dull. Color grayiBb, green- ish, brownish, velvet- black. Streak browDiBh blacky grayish, olive green, a little shiuiDg. Opaque. Frac- ture conchoidal, uiieveu.

Aulunite Uranium Phosphate, — H. 2.0 — 2.S. G. 3.0 — B.% Luster pearly to subadamatitiDe. Color citrou-yellow to aulpbur-jellow. Streak yellowish. Tranalucent.

TorbeTnitCt Uranium Phosphate, Copper Vranimie — H. 2.0—2.5. G. 3.5. Lueter pearly to fiubadaman- tine. Color emerald and grflee-green, and aometimea leek, apple and aiakin-green. Streak Homewhat paler than the color. TraDslucent. Sectite,

(The above are ijstially asBOciated with silver ores.)

ViNAniUM — Vana.din.Ue or Vanadate of Lead. — Usu- ally ID impla&ted globules or in cfu station a. H. 2.75 — 30, G. 6.6 — 7.2. Luster of aurfaoes of frac- ture resiuouB. Color light browniah yellow, etrqw- yellow, reddish brown, S'jreak white or yellowiah. SubtrauBiuoeQt to opaque. Fracture uQeven. Brittle.

Chaffer Xiv.

Useful Eabthy Minerals, Etc,

1. Inboluble.

The value of the depositB of the various mineralB grouped uuder tbie heading Uepeuds on the ptirity of the article, the quantities m which it is found, the coat of labor and the facilities of trauBportatioi], de- fective oonditiona on any one of these points takiug: the depoBit out of the list of commercially available propositiong, as tho market value per pound of most of them is exceedingly low, and the number of locali' ties in which they are found proportionally reat; while for some of them there is only a limited demand.

Asbestos is one of the few well-hnown minerals, its white or greenish white or bluish dbrous appear- ance being BO chflTucterietio as to be familiar to all prospectors. In silkineas it may rsingo from Ion g exible fibers like flax to brittle eaithy masses. It is tk widely diseminHted mineral associated with rocks which contain large quantities of horublende or HUgite, it being one of the pioducts of the metamor- phism or decompositiou of these rocks, and is conae- queatly common among the hornbilende-achists and serpentines, which also produce chrome iron and soap- stone, all three minerals usually occurring in the same locality.

The threat dicnlty connected with the mining of this substance is the large iiuantity of material which

S30 Phqspegtinq Amd Yalui2/G Mines.

must be handled to secure any quantity of aebeetos, aa it usually oocurs in smaJl threadB, BtriDgtire seama or pocketa, irreiulary scattered thruugL the coDtain- ing rock, so that it must be -worked lu open quarriea, and the aabestos soited by hand from the rock. It varies greatly iu character, from short earthy fibers which are brittle and separate with diiHcultyj the atruoturo runniiig across the aeam and not parallel to it, up to loug fine silky threads of a pearly white color Ter3' much reseuibliug ilai. The term "amianthus" is applied to this last variety. The longer and more flexible the fiber, the more valuable the mineral. Asbestos is iufusihle, but the common notion that articlea made of it can be thrown into the Are aud thus cleansed of accumulated dirt, iserroDeouB as at a red heat the tibers lose their flexibility and become brittle.

It is uaed in the making of fireproof paints, rooling, piston packing, Talva packing, covering Bteam pipes and boilers, fireproof cement, sheet and rolled mill- board, flooring felt, textile fabrics etc., being often used in cumbinatLcn with hair felt and other sub- stances. It derives its value for these purposes from its indcBtructibility in ordinary firea, and the resist- ance it offers to the radiation of heat, a property which it possGsaas in common with wool, cotton, feathers and other substances which cannot be safely used in the presence of high tempetatuica. For fireproof paiuta the length of the fiber is not essential, but is a desirable quality for puckinss and the covering of steam pipcg aud boilcra, while it is essential in all textile fabrics.

Asbestos being associated with well-marked belts of rock the proapector should familiarize himself with the character aud appearance of these rouka at auy locality where he may find asbestos, and having done so trace this belt along; the mountain range, as it will be comparatively useless to spend time an the rock strata which lie either above or below itj eseeptiag so

USEFUL BAETSY MINERALS, yyf

far as they may help him to locate tbe position of tba asbestos belt, 'n'here it ib covered up by earth or debris, or not otherwise traceable.

Asi-HALTUM. — Amorphous or Tvitbout crystallinQ atructurti. G. 1 — 1.8, BometimeB higher from itn- purities. liuster like that of black pitch. Color browniBh blaok and bLack. Odor hituiuiuous. Melta Visually at about 194° to 212'', aud burns -with a bright flde. The more solid kinds graduate iiitoiuiDeral tar and through thie there is a gradation to petrnleuiu. Asphaltum aiipeara to be a residual depodt, derived from the evaporation of petroleum pioJucts. In the United States the production is confined to the West- em tates, the depoBitB {which are alwaj'S found on the Burfflce or near it) occufring in California, Utah and Colorado, being either fairly pure or mixed with earthy matter. The principal source of foreign supply is the island of Trinidad in the West Indies, where, at a place called La Brea, there occurs an asphalt lake of about 100 acrea in extent, the product of which is (shipped to Europe and the Atlnntio Beahoard of the Dnited States. In Europe a limegtone, naturally ami evenly iiupreirnated with bitumen (or aephalt), is largely used with good reultB.

It is UBed for many puriiOBea where a surface imper- meable to water is required, combined -with toughnesB. Natural asphalt rock, and asphaltum in combination with other materials, are used in the surfacing of etreete and Bidewalks, aud the finishing of roofs, AspLaltum makes a durable coating for 'water-pipeg.

Bahytes. — Th ] B mineral, also called "heavy epar/ because of its great 'n-eight, iu a sulphate of barium. Its Bpeeifio gravity is about 4.5, -while that of lime- stone is only 2.6. It ia an earthy mineral resembling limestone ranging in color from white through eLadeB of yellow, eray, red and brown to dark brown, accord- ing to the amount of impuritiea present, but vrhen crystallized has a vitreous or glassy luster and a white

232 Prospecting And Valuing Mines.

streak when scratcLed. Some BampleB wben rubbed give off' a fetid odor. Xt is cot affected by acide and may tbus be readily diatiDguisLed from the Hmestoiiea liv'ith wbicb it 'Baay be associated, as well a& by its weight, which ia much greater than Q.ny of the similar minerale, such as gypaum and carbonate of magnesia.

It ocoure in veins and beds aeeociated with lime- etones, sandstOEes acd trap rocks, *nd not infrequently forma the gangue wholly or in part of metallic veinS;, especially those of lead. The mineral is widely dis- tributed, occurring in beds in eandstonee in Connecti- cnt, and atlBleEoyal, Lake Superior; in beda in lime- stone in Iowa snd New York; and in limcBtone and associated with lead ores in Missouri, North Carolina, Tenneseee and "Virginia. On the northern shores of Lake Supefior 'veina occur iu trap rocks.

Barytea is used iery exteneiTely m the artsi, biit almost altogether for purposes of adulteration, for which its leading use (about SO) is in replacing to a greater or le&s extent whitia lead in paint. The claim is made that a mixture of one-third white lead. one> third oxide of ainc and one'tliird "floated" barytea makes a better paint than pure white lead. It is also employed as a "filliug" for general purposeSj in pulps and in making putty and pottery. The value of ground barytes being not much over one cent per I pound it is evident that only the purer deposits and

those best located for dressing and transportation can be made available. It must be free from grains of quart7, iron rust aud other impurities, and of a good white color*

Bauxite. — Q. 2.5. Color whitish, grayish to i'el- low ocher, brown and red. Ocours in round concre- tionary diasemiuated grains; also massive oolitic; and earthy, clay-like. Bauxite ocours in the United States in the Coosa Yalley Georgia and Alabama, in clay beds along the line of an extensive fault in lime' atone rocks, the beds having apparently accumulated

lODs eroded along tliia tQiiit, no eruptive looks beinjj preseut; also in Arkaiisaa, in regularly itrHtified beds near the contact with eruptive rooks, fliid in France Qs a residual deposit from the decay of iJQ rocks. In Styria, a deposit 12 ft. thick occurs fti the junotioa of tbeTriaasio and Jurassic formations. The favorite aBSOciatlons appear to be limestone and waptive rocka.

Frod the large amount of aluminaprsent in bauxite itiorm&a valuable source of aluminum, and the purer Tnrietiea are largely used in the production of that wta], b&ing known a3**aluminum ore." On the Con- tinent of Europe the product of the quarries at Bans inTrauofi, from which the mineral takes its name, is bJbd ugd aa a flux in iron smelting.

Itiadiflficult to give a oonciBe description of this raliiftble ore, but the following extracts from 'Mineral luduitry," "Vol. 11. , will probably be sufficient to call stteution to its chief peculiaritiea, oud to suggeat the ility of submitting siiRpected samples to Bauxite hae few ereeially distinctive char- acters eieept its usual pisolitie (pea-like) or concre- I'ODsry obaracter, which perhaps accounts for its hav- ing been BO long overlooked, and for the comparatively iflw loaalitiea where it ia known to occur. The red 'Rfiety of bauiH© was tbonght to be piaolttio iron ore liDtil ita true character was shown by analyais.

'Bauxite is uaually a concretionary or pisolitie min- "al, though eometiraes it is a hard compact, homo- g&aeous, fiue-grained rook, commonly oolitic (made "f of round egg-like fragments), and sometimes an fiftrtby, clay-like raaterioL It may therefore he hard, or Boft and friable, compact or porous, but the best,

lea are hard and have a metallic ring. The con- ioQs vary in aize from small peas to large bowlders, hicli are cemented together by fine-grained liard iJaiisita, bauxite clay or silicious material. In nearly very case, however, the concretions or nodules are

234 PnOSPSCTlira AND VALUING MINES.

better mineral than the ceraentiug materia!. The con- cretions, nlso, Are usually harder than the cementing material, especially in the surface ores.

the surface, bauxite beds are generally marked by hard, rough bowlders or loose uoJuIes and pebbles in the top soil. Below the surface, however, the nod- nlar audi pebbly oreg are often com par atively soft and orumbiy, and the ootnpaot oi3litlo and fine-grained orea are Bo:aetiTne8 a aoft powder.

"Bauxite varies in color from almoHfc pure ivhite to a deep red or black. It is also of cream aad pearl- white color, grayish, yellowish, amber pinkish, and speckled or mottled, . . . These colors often shade into one another, sometimes suddenly atid eoiiie- tlmes gpadimlly, and it is seldom, if ever, that a bank or depaeit is wholly or uniformly ot one color. "

Clays are eBsentially silieatea of aliiuiua with combined water (hydrated aluminum silicates), but Tary immensely in composition, not only from differ- ences in the amount of silica and alumina present, but also from the presence of impurities euch as litue, soda, potaab, eand, nuagneaia and iron oxidsa which affect the fusibility of the mass. It is these differencea which render them suitable for different purposes. For commercial use they may be classed as fire clays, pottery and kaolin clays and brick clays.

Fire Clat/ — .The presence of alkaline matter andiron oiideo tend to promote vitri6oatiou, and on excess of alumina causes shrinkage in burning, so that a good fire clay should consist practioally of silica and alumina, with the smallest amouut possible of iron and alkali, it being possible to counteract the contractibility or shrinkage by the addition of quartz sand. The pres- ence of an escesaof alumina, however, renders the clay more tenacione and plasiic, but this is not essential in a firebrick, though desirable in pottery clays. The following table shows the relative oomposition of five English £re claya and 14 American samples:

V8SFUL EAfirnr MINERALS.

AHAiTSES OF FSBE 'OLA¥S.

EhigUah American.

Km

21,70 38. Bl

The English examples are all from the older coa! meBBiiree and sliow as compared v/ith more recent claj samucli less percentage of olumiDa; the AraericBn eamplea are from the clay depoeits of New Jersej-, PenDsylvimia, Maryland, Illinois and MiBBouri. The great esseutial in. fire olays is tliBttiiey ebould not con- tain over 4%" of jmpuritiea.

Brick Clays. — From the most refractory all grades occur to those which fuse or Titrify with the greatest ease, and the adai>tabilit3' of atiy deposit to a special purpose is best detei'ioint by trial, it beiiig;> hoTV- ever, iraportaiitj if ths bed ia to be worked on a large Bcale, to ascertain if its compoaitiou ia nuiform throughout. For_ briahmnking, the presence of lime is a detriment, as if inauflBciently ground the nodules of lime, haTing been converted into quicklime whils burning, will afterward absorb water, expand iiii the process and crack the brick.

Pottery CTni/s.— Eaolin, which 'hen pure ia com- posed of silica 4G.3, aluujiiua 39.8 aud water 13.9, ia the result of the decomposition of the feldspars in granite rocks and porphyribB, and furuisheathe mate- rial for the finer grades of tihinaware and porcelain, after a thorough preparation by washing and settling, until the residue ia an impalitable creamy paste. Very large ateasof these rooka, in some lociiUtiea, have been thus decomposed; but the presence of an excesa of iron oxides, which would color the finished product.

pRosPEaTmo AND vALumQ itmsa.

or otlier iropurities, reDder the bulk of them suitable only for inferior grades of obinaware.

CoBtTNurM AND EsiEHT.— "H. 9. G. 3 to 4.1. When uryatallized the luster is 'vitreoue; color blue, red yellow, brown, gray and nearly white; atreat un- ooiored. Transparent to translucent. Fracture con- €boidal, uneven. Exceedingly tough ben com- pact- ' ' (Dana. ) ' ' These BubBtances (ooru Ddum or fiapphire and emery )j bo nefii'ly allied mineralog- ically, are sharply dietinguiabed in the trade. Mm- eialogically tbe former is a nearly pure alumina, while the latter contains a large proportion, from 20 to 33%, oi iron oxide. The trade dlBtinetions are somewhat as follows; Emery is always black, while corundum is of varioufl colors though more frequently gray and never blaok. It ie much harder then emery (taking the eappbire at 100, Dana gives the abrasive power of corundum at 62 and emery 4(>) and Bbarper, cute deeper and more rapidly, but is on the other hand more brittle aud coneequently lees durable.' (Gan- nett.) These minerals are associated with crystalline rocks such as granular lirqeatoiiej gneies, granite mica and chtorite scbiBta. The emery of Asia Minor occurs in granular limestone. All of the corundum used in the United States la of domestic production, from localities in the Appalachinn range, extending from Maine to Georgia, and from some western poiutH aa Colorado and other States; but these lattef are recent developraents and ae yet comijaratively amall pro- ducers. Both corunduiB and emery- are chiefly used for grinding and polishing metals and other hard aub- stances.

CaTOLiTE,— "H. 2.5. G. 2.95. Luster vitreoaa or glassy ; slightly pearly on some faces of the crys- tals. Colors now white, sometimes reddish or brown- ish to brick-red and even black. Subtran a parent; immersion in water iocreasQB the tranaparency. Brittle. Fusible in the ilame of a candle. Occura

USEFUL EARTHT MlMERALa.

sparingly in the crystal beds sear Fike'a Peak, Colo.; but is a rare mineral in tlie United Stutes. The prin- cipal foreign locality iB at Evigtok, in West Green- land, where it constitutes a large bd or vein in gneiss, and containH ga!eiia zinobleude, carboDate of iron, iron pyrite, arsenical ].>yrit6, fluorspar, tin oro and coluistitd, till of tbetu frequeotly ia tiue crystals. Taylor statee that tbe cryolite ia not white, except within 10 to 15 ft. of the surface, and that bfilow this it beooiues dark-colored and even black- The coD' taiued ores aud other minerals are moat abundant near the junction with the gneiss,"

Cryolite ia a compound of fluorine, alumina and soda, and used in the maoufaoture of the latter article, and also in the produstion af aluminum (along 'witb bauxite), as well as an ingredient of a white, poruelaiu-like glass. The main supply Is at present derived from the Greenland dopoaita.

FLuonapAE.— H. 4, Specific gravity 3,2, Streak hite. Fluorspar ia a glasby-lookiug miueral, nearly transpareut when pAle in color, which crystal- lizes in square cubes. In color it baa a wide range, varying from white to yellow, green, blue, violet aud red, the eommouost colors being white, pale green aud violet. The green varieties look very much like bottle glass. When crystallized, the ftpecimena are very beautiful. It occurs in veins either by itself or as tbe gangue of lead ore, and as beda or mitsses in lime- btones, and is found in varyiug tiuantitiea in almost every State of the Union, but not very freiueutly in workable quantities. While apparently preferably found associated with limestonee, it also occurs in veins in granite gneiss sandstones and elates, and as a component of sueb rocks as rhyolite. Fluorspar ia used as a dux in Bome lead and copper smelting upcru< tions, in the mimufacture of hydrofluoric acid for etch- ing ou glass and seals, as a glaze for I'tottery, and in the production of aluminum.

333 Prospeotihq And Valuino Mwes.

Graphite OB Pi,nM:BAQo (algo often OfiUed "blact- lead"). — A soft stiQel-gray to black minex'al with a me- tallic ]uBtei% and greney feel; upaque; etreak blaok and ahinlng; can ba easily cut wiih a knife and goila the fingers in handling. It is nearly pure carbon (con- taiuiuj no lead sua tho common name might implf ) and resembles uo other mineral except molybdenite which is lustrous lead-gray in color, with a streak inclining to gray, aod marks paper gray inatead of the pnre black of gvapbite. Gritphite occurs in reins, beds, and diBaeminated in fine particles through some schistose rocks, called grapbitio scbistB. It is con- iined to the oldor rocks, but is a widely disaemixxated mineral. Tbe veins are true fissures in gneisaoid and eruptive rocks. Tba veins produce the soft crystalline and foliated foriuB, which are tbe purest and most valuable, Graphite alao occurB in beds, but is usually more or less contaminated with impurities, and lees valuable comuiercinlly, tbe ores generally being of such a L'liJinioter tbat purifieiition ia impossible. Xha graphitic schists which are fuuud hi the same regions as the veins are metamorphosed saudetoneB or slates with foliated graphite very evenly distributed through the mass in small flakes, giving a deep black color to many of tbe slated. The localities where graphite occurs in more or less quantity are very numerous, but from this fact it is only those which produce the very best kinds which have any commercial value.

American graphites come into competitiou with those of C&nada and Ceylon. In tbe latter iaHaad the mineral occurs tn veins of immenae size and great purity aod is shipped without any preparation except sizing. Graphite ia used in the manufacture of cru- cibles, stove-poiiah, lubricating compounds, foundry- facings, lefid pencils, picking, paint and electrical supplies, and also in electrotyping, etc The first three iuduetvies cotisume 75% of the production, the constimiition for pencils being only about Z%.

Useful Earthy Minehals.

Gtpsijm ( Sulphate of Ltme), — H. 1 , 5 — 2.0. G. 2.3 for pure crystftla. Luster shin.Vj pearly to TJtreoUB. Masaive VHrietiea often gliateoiiig, ' aome- timee tlull, eiirtby. Color uaualb Lite, somelimeB gt&y, flesb-red, honey-yellow, oober-yellow, blue; im- pure YuriefiGa oftsn black, browD.red or reddish brown. iStieGlc wbite- Transparent to opjique. Inftddition to the abore characters it may be mentioned that the crya- tale are fiat or tubular, and that the crystallized vane- ties known as selenite split readily iuto thin trans- parent sheets "n'hicb are flexible, but not elastic; and that when burned it forms plaster of paria, which iiardenE proraijti.v on being toised with water, tbua differing from ordinary liraestoneSj wbich also require a much higher temperature in burning.

Gypgufn in one or other of its forma is found in large quanttties in most of the fcstatea of the Union, in 3annectiou with deposits of rock salt, bein; impreg- xiated with sulphur. The association with rock salt ia 3ue to the fact that gypsura is a produot of the evapora- tion of sea water; as well as a product of lime-hearing Xninerala under the action of decaying iron pyrite. ' Ibis latter action esplnina its presence in vein matter and in clay beds in a crystallized form. The name idrtster of paria is in allusion to the large production of that article ct the gypsum beds of Montmnrtre near TPtirie, which ore mined on a very exteusave scale. *'Selenite" is the term applied to the transparent crys- tallized varieties f when ailky and fibrous it is knotrn as "satin wpar;*' fine-graiiied varieties, delicately tinted and suitable for the manufacture of ornaments, are known as alabaster or onyx, the latter term being erroneously employed, "The principal use to which gypsum is devoted is an agricultBral one. The ground rock or land plaster, is applied as a top dresa- iflg to the soil 5 and although it does not enter directly to any extent into the composition of plants, it has etill an estremely beneficial action upon plant life and

240 Pmospecting And Valuing Mines,

growth from the chemical cbauges which it induces in the aoil. Stucco, plaater of paris, or calcined gyp- sum, IB used for making cornices, fiiezes and other forms of interior docorationa the finishing of watlSj etc. The finer grades are naed in taking oaata of natural objecta making models etc."

iNPLiObtUi Eaktu, tripuli, oriuoutitain meal, consists entirtily when pure of the ailicious skeletons of micro- Hcopic Tcgetable orgauisniB called diatoms, and in this leBpect differs from chalk, 'n'hich ib similarly made up of the infinitely minute shells of animal organismB called forarainifara, but which are flompaeed of lime instend of silica, and ijonsequently efferveece when treated with acids, which is not the case with infuso- rial earths. Deposita of infusorial earth often cover many square miles and may he pure white and chalky in appearance, like the deposit at Ked Mountain, north of Virginia City, Not., the origin of which must be of comparatively recent date, geologically Breaking, aa the writer has found in it remainB of insects now Jiving in the neighborhood; the deposit at Santa Flora, Tuacady, congiata of a grayish white loose, earthy meal, and simul&r matenal is also found in Spain. Tripoli or polishing elatej is a fragile, slaty or thinly laminated variety often much mixed with impurities Buoh as clay, magnesia, etc. Other coneid- erable deposits of differing character are fouiid in Nevada and California. Infusorial earth was at one time largely used as an absorbent in th& manufacture of giant powder, but has given place to wood pulp of late yeaiBj and is now u&ed almost es.clusively to give body to soap, and as a polishing powder. The Eed Mountain deposit is simply pulverized and put on the market under the name of electro-silicon being an ex- ceptionally pure article of eilica, showing less than half of 1% of impurities. The demand is limited.

The harder, comimct varieties, such as that found in Newton Couutj', JIo., are quarried and shaped into water filters, which are of esceilent quality.

rrSSFUL EARTHY MINERALS.

XjDIESTONE, ia its various forma of ordinary etoue or marble is too wlJ kaowa to need further descriptioa, and is fauud abiiudantly in all the States of the Union. The production of 'luicklime for building purpoaea aiuounta to over 60,000,000 bbl. of 200 lb. each, involving the qiiBurying of over 12,000,000 tone of rock. This does not include th;it mined aa us for smelting npefffltioos, or ".married as building stone. Provided the lima is free from iroQ m appreciable quaDtitiea the color is of little consequence to the biirnerj, as it dia- arpenrs under the action of beat, and the product of blue limestone and white marbla are not to ba dietin- guisheil from each other. The presence of iron ia objectiouable, ns it would rust in the mortar and when leached oub bv rain would stain the buildJDg. Mag- nesian limeBtonea or dolomite, have usuaHy tinges of yelloWf buff or drab, instead of tending to blue tints, and are used in the manufacture of hydraulic or quick estting cements. The value of marble depends largely on the fineness of the grajin and the purity, beauty or pGcnlisTity of the coloring, but with all the good qual- ities at a masimum the deposit may be valueless if unfortunately situated as regards cheap transporta- tion.

It is desirable that limestones used as £ux for iron smelting should be free from phosphorus, just as the sajue quality is desirable in the fuel, because nearly the whole of the phosphorus present, both in the ore> fuel and flus, will be ooneentrated in the pig iron produced, decreasing its value materially and render- ing it totally unfitted for many purposes, especially the production of Beaaemer steel, which requires a practical absence of phosphorus in all the material which goes into the blast furnace.

Impurities in the limestone used for making quick- lime, especially silica and alumina, have a teudenoy to vitrify, or melt into more or less glassy particles, dur- iog the prooess of burning, and the product does not

343 Pr08Pectinq And Valuing Mines.

elake into as smooth a paste as that produced item purer rocka, but tboBci 'poor" limes are said to mnkoi*' a mortar which is able to resist the destructive Action of atmoaplierio agencies better than tha "rich" onea, being apiMrently leas soluble in rain water.

Limojtaiio ia so abucdADt a material in natijre that we need in tbi& place oall attention only to one par- ttoulur variety used for lithographic purposes. There is no absolute ohemiaal compositioti, aualyses showing a Tarying amount of carbonate of magneaium (2.50 to 17.32%) along with the carbonate of lime and various smailqiiantitiesof otheraubstances. The stonofiin um* are usually shadea of drab or gray, and they must beg abeoUtely of uniform composition throughout, some — what porous and soft enough to work easily under the: ongraver'a tool, but tough enough to bear oonBider- — able pressure in the printing press. Such a stone wilKl be rery line-grajned and break with u shell-like (oon— —

oboidal) fraoture. Only actual trial will prove the

suitability of a particular stone, but localities which produce good stones of large size, eay 40 by 60 in,, eitremely valuable.

Maonesite ia a carbonate of magnesium, white ii color when pure, but shading into brown when iron present. It is maderatBly hard, tough, and breakff with flat conchoidal surfaces and is somewhat heavier than quartz. It looks something like limestone, but is only feebly acted on by cold acids, though when powdered it dissolves readily in warm muriatic acid with effervesoencB. It is usually found in connection with flerpeutine rocks, talcosescbists, and conaeqxientiy with aoapatone and asbegtos, all of which are naagne- sian products. The ore ia used chiefly in the manu- facture of paper from wood pulp, and as a refractory lining for furnaces using the basio process for ateel making.

Mia* ranges in color from white and very pale greenish and brownish shades through dark brown to

MaflTr, T

Useful Earthy Minerals. 243

blact. It splits easily into very thin sbeetsj Bome- timea as mauy as 160 to the incb which in the paler colored varieties are transiiareut, but only partially so in the dark oue&. Tbeae thiu plates or laruiiis are ilesible and not easily fusible, and in this reaped differ from crystallized gypsum or sulphate of lime Tvhich while HeparatiDg into very thiu flakes is not Hexible, and when heated crumbleeinto a fine powder, the plaster of paris of commerce. The two are often luistakeQ for each other and confounded Udder the common name of "isinglass," which is really fiah glue or a compound prepared from gelatine, and an organio product. "When scratched or cruBhed the result is a whitish powder eteti in the case of the dark varieties. Mica is a common constituent of grnite gneissic and schistose rocka and is found in many loealitiea in ci'ystals of larger aiae than those usually forming an essential ingredient of the rocks mentioned. Suah crystals have been reported from North Carolina and the other South Atlantic States; Maine, New Hropehire, Pennsylvania, South Dakota, New MesicOj Wyoming, California and elsewhere. It has been found in almost all the Pacific States but not in workable quantities of good quality. South Dakota has produced plates 12 by 18 in, in size from a vein which is said to be 14 ft. wide, and to consist of a central tnass of feldspar and porphyry with a casing of mica, which varies in width from 3 to 4 ft.on each flide. The country rock is granite. Clear, transpar- ent and tough mica plates are used in various ways, the prindpal utilisation being for stove and furnace doors. A small amount of specially Hoe mica is used for flompasB plutes. The inferior varieties not suitable for the above uees are largeb' used as an insulating substance in electrical machinery i while the scrap trimmings of the better kinds, as well as larga qiianti- ' tiee of the inferior sorts, are pulverized and used as an

24i PBOSPSCTING AAD YALUJNG MnTES.

the composition of lubricfttiug compounds; as well ai for various orwamfnatal purposes in the arts.

Mica ooly in plates of larige size and good cdIo: has any high oommercial value. Yot such plated tlie price iucreasis more rftpidly than the &ize of the pUtes, which may be said to range in valufl from 25ti. to %b per lb., \7ith occaBionaHly higher prices for exceptionally large anil goud plates. iiiduatry in the United States fluctuates very greatly both iu the Quantity produced aud its average Talue ohiefly owisjg to the uncertain character of thi deposits, -which may suddealy become worthless*

I'rom the peculiar conditions of the mica trade it is evident that good, large plates can bear aomewhafl high rates of freight, aiid can be worked in out of thaj way localities, but if of only email or moderate iz&j[ the necessity for cheap labor in dreaeing and cutting the blocks, and freight charges, may render deposit valueless, eEipecially if the cost of mining is high as large quantities of material must often hm moved to secure a few pounds of plates, the condition being very much the same as smrouad mining foil asbeatoB. '

The scales of jellow naica, found in the streams o; granite and schiatoae mouutaiua, are frequently mig. taken for gold by tlie uninitiated, but can easily hi diBtinguished by their softness and light \\'eight, ai -well as by their loss of the yellow color when groun to powder*

OzoKEBiTE.- — Like was or spermaceti in appearancfl and consistency, G, 0.85—0,90. Colorless to white when pure; often leek-grean, yetlowiah, brownish yellow or brown j and -when brown, Bometime* green hy trnnsmitted light through thin shaviugs. Greasy to tlie touch. Melta at 133° to 14G° F. Burna readily in thin shaTings or at the ftugles of specimena when ignited with a match. (Duns in part.) Ozoker ite, 01 natTe parafQnf is not a common product it

Useful Eaetey Minerals.

nature. It occurs in beds of ooal or associated with

bituujiiious aubatsDces. Id the United States it is

found ID Utab Abroad it occurs at Slanik, Moldavia,

beneath a bed of bitumiDOUS day sbule; in maBBes of

SDiuetimeH 80 to 100 lb., at the foot of the Car-

patbiausj not far from beda of eoal and salt; that of

Boryslau in a bituminoua mlay, associated with calcif-

eroii9 beds iii luasBes. It is also reiiorted from the

Carpathiau saudatOQeB iu Ti'anflylvaiiia and other less

important loeaHtiee. Ozokerite, mineral was or

natire paraffin Ib used ia the mauufacture of candlea

and heavy lubricantB, very extensively as an meulator

for electrical wiring, and generally aa a Bubstitute for

most of the uses of beeswas.

FuMJCE Stone is an exceedingly porous, spongy- loukiug lava in vrhicb the air bubbles are ao numerous that it will £.oat on water, and varies iu color from dirty white to pearly gray. It aside from its uee as a toiJet article, is chiefly employed in polishing marble. The bulk of the article ia imported in the lump for use in the Eastern States from Italy, where it ie found nbundaijtly on Mouiit Vesuvius i while most of that used ou the Faciflc Coast is produced in California from deposits tljake Honda a few miles south of San Francisco. Other deposits of good quality also occur in Cftliforuia, near Mono Lake, which is the crater of an e:stiuct volcano, and at Little Owene Lake and other localities in Inyo County. The annual con- sumption is not large and the price low, bo that cheap transportation is essential.

Quartz.— H. 7.0. G. 2.6. Luster vitreous or glassy to nearly dull. Calorlcss when pure| often various shades of yellow, red, brown, green, blue, purple and black- Streak white of pure varieties; when impure often similar in color, but paler. Transparent to opaque. Quartz takes many forms, aad is one of the commonest minerals;, but is chiefly used commer- cially iutbe condition of sand, sandstone or quartEite.

S4U

PROSPEGTINQ AND VALUING MmES.

Beds of sand and BaudatDue are common eTerywberei but tboy are nut all HTailalile for the aame cJasa of work on account of the asaociated impurities, and their Tulue for any particular purrase can only be thoroughly ascertained by working testa.

Tbe tinsst kindt) of trauBparcnt quartz, knoKvn as "roek-crystal," are or rather were extensively used in the manufacture of spectacle iglaaaes, but tbe impiOTe- ments in lasa making have diminLsbed this applica~ tion. Similar quarts is used extensively in glass and pottery making, and as a grinding and poliahing powder. Ground quartz is also used in the manufac- tura of sandprer. In addition to these a peculiar variety of eandfttone called "ganister" is largely used in the lining of vessels used in ibe manufacture of steel on account of its exceaBively refractory character. Ln England the g:ani8ter preferred for lining is a peculiar ailscioug deposit found under a thin coal seam near Sheffield, of almost conchoidal fracture, thereby differing from ordinary sandstone, and containing a few tentba per cent., or Hometimes a little more, of lime, and the same amount of alumina 'n'itib small quantitiea of iron oxide and alkalies, the rest being silica; analagoua aubataucea are found, however, in other localitiEtB iu tbe northern coal iields. Beds of aucb quartz in the vicinity of steal works are valuable.

li'or mortar making river gaud is preferable, aa salt froru sea sands will certainly make its appearance on brickwork where it is used, spoiling tbe looks of the building as well as being objectionable on account of absorbing moisture; it is also sharper, with leas rounded angles, as in rapid streams much of it is car- ried down suspended in the water and the angles scarcely suffer any abrasion.

Stkostia, Steostianite, Eto. — The metal strontium occurs as a carbonatOj under tbe name of etrontia- niie, and asaBuiphate,underthe name celestite. When crystallized etrontianite has a hardness of 3.6 — 4, and

Useful Earthy Minerals.

a specific gravity of 3.65, with a vitreoug or resinous luster, and white Btroak. lu tjolor it is pale asparagus- green or apple-green; white, gray, yellow and yellow- ish bcown. TrauBpareut to txautiluceiit. (Dana.) It occurs in tbe Uuited States in granular and cciumnar masses in hydrauliu linieBtoiies at Schobaiie, N. Y. ; and at Muscaloiige Lake in the Baiue State, a luaBsiTe and fibrous variety of a white or greenish, white color ie found nsaociated with fluorspar. In Scotland it occurs in velbe traversing gneiss, along with galena and bante (haiytes). (Dana.)

Celestite has a hardceBs of 3 — 3.5 and sp. gr. of 3.95, being somewhat softer and heavier than stron- tianite. The luster is vitreous inclining to pearly when crystallized, and the etreak white. The color white often bluish (from which it takes its name) and sometimes reddish. More or less transparent, (Dana.) Celeetite is uauully associated with limestone or sand- atone, and occurs also iu beds of gypsum, rock salt and clay. (Dana.) In the United Statea it is reported from the limestoneB about Lake Huron; from New lork and Penney ivansa, and also from Green orStron- tian Island Lake Erie.

Nitrate of strontia is used to a considerable extent by the makers of tireworka for the production of red £re. The use of strontia has also been proposed in the treat- ment of beet sugar, and in the manufacture of tuyeres for blast furnaces. Sicily furniahss the bulk of the mineral at the present tinie, but little search for it having been made in the United States on account of the small demand.

SuLPHUB cannot be ZQistaken for any other mineral, its brilliant yellow color, and characteriatic odor on burning separating it instantly from all others.' Wherever found it appears to be aggociated with vol- canic action and hot springe, having been deposited by such agencies in vast beds both in Europe and Aiaerica. In boxing for petroleum near Lake Charles

248 Pl£0SPe0Tl2f& AND VALUiNO MIITES.

Calcasieu Fariali, Louisiaoa, "at a depth of 423 ft. the drjU passed through 100 ft. of pure sulphur and 148 ft. of gypHuiQ mixed with Eulphur, the former mineral beitig a oommoii associate of sulphur deposits, by the GODveiBiou of ordinary UmestoQG iuto the sulphate through the action of sulphuric acid. lu Nevada, tbo beds near Silver Peak are traversed by Beams of alum, formed iu a similar way by the decotapoaitiou of aluminous or elay-forming rocks. Iu California at the Sulphur Bauka in Lake County, the depoeita are aBSOciated with cinnabar or mercury aud borax. In Southern Utah the ocourrence is evidently in whatwaa furmerly a crater of a Toloano, about three miles from Fort CoT€ Creek. The crater forms a small basin sur- rounded by 10T.V hills with a narrow ravine opening into the plain — probably a breach in the old crater walls — which coosist maiuly of andesite with some pale whitish trachyte (both porphyries) with obsidian splinters scattered over the surface. As far as explored the sulphur beds extend over an area of at least 1,800 by 1,000 ft. across. The sulphur shows upon the sur- face over part of the basin, but is raostly covered with fiand, or rather the dia integrated andesite of the sur- rounding hills. A curved cut through the western end of the deposit exposes a vertical wall of rich yellow sulphur 34 ft high, from which iu many places, as well as in other prospect-holes, grases escape, together with water holding various salts iu solution." "At the Mammoth claim in the satue neighborhood, the slates aud limestones are impregnated with sulphur, gypsum being also found as a product of altered limestones; while at the Sulphur King claim the andeBites are similarly saturated.

The deposition of sulphur is constantly going on at volcanic vents and many hot aprings. "Mount Purace, in Colombia, wears, a cap of sulphur (derived from its own crater) which accumulates at the rate of 2 ft. per annum — ita auperiicial area amounting to 1435 sq.

U8Eful Earthy Mwerals. 249

3'arda;" audtbe sulphur forming; in the ciater of fopo- oatapetlj in Mexico, is regulnrly worked by tbeludiaus. The Bfllfatara of Babara Sapbiaauo on the Red Sea la aaid to yield 600 tons of sulphur auiiuaUy. American sulphur cornea iDto sharp competition with that pro- duced by the Sicilian deposits (which have been worked to a depth of over 300 ft. and turn out annually 400,000 tons of clean sulphur), and cn conBequButly only be proHtably exploited under tbe most faTorable conditions of labor and tranai>ortatiou aided by local demandj which it fostered by the high rates of freight on sulphuric acid on account of its dangerous char- acter. Native sulphur is aleio met in the mai-ket by acid produced from iron and copper pyritea, which are now mined in enormous quantities for that purpose, ae the contained metals furnish a valuable by-product.

The larger portion of the entire product of Bulphur is used in the manufacture of sulphuric acid, the oonsumptioQ of which in manufactures is extend- ing daily- Outside of this it is employed in the pro- duction of Tulcaniaed rubber goods; in the manufac- ture of "bluestone," or sulphate of copper, which is largely used in metallurgical operations ; as a preven- tative of and cure for mildew OQ plauta by horticul- turists, and many minor uses.

Talo AND SoAPSTONR. — H- 1 — 1.5. G. S.fiij. Luster pearly. Color apple-green to white, or ailvery white; also greenish gray and dark green brownish to blackish green and reddish when impure. !treuk usually white; of dark-colored vaiietiea, lighter than the color. Easily out with a knife. Thin sheets flexible, but not elastic. Feels greasy. (Dana.) The foregoing description ia of the purer and softer varieties, from which theharder kinds are aeptarated as "soapBtone," to the best kinds of which the term 'French chalk" is applied. The mineral is soft enough to leave a whitish mark on oloth and is used by tailors in drfi'ving their pattern:. The various f orca of talc are

50

Prospeotinq And Valvinq Mines.

uf very common oocurreiice, and Bteatite or soapstoue fui'ms extcmeive bede in some regions, beiug often usaociated with aerpeBtines, chloriticor talcoee scbista, iu wliitih lutter rock thin Hakes of talc take th place of mica, and impart to it a certain greasy feel, which Ib characteriatic of tlie entire series of ojiiiQrals asBo- eiate<2 under the name, wLicli is often applied by miners and proBpeutora to any Boit rhite earthy substance in the gouge of veins, whether greasy or not. Talo is XMBed exieDBiTelj in soap making, and lu dressing fine sheep-skins, leather, glovea, etc. The finer, soft, foli- ated variety ia uaad in the manufacture of paper and BQjall Liuantities enter into tb composition of some lubricating compaunds, ''Soapstone," on account of its refractory nature in the presence of intense heat, and the facility with which itoan be Bawo into bricks, slabs or any doBirable shape, is extensively used aa a lining for sLoves, furnaoea, etc. It can bo easily turned in a lathe, and the vrriter has seen on the Mexican border a very ancient tuyere for a bl&ck- emith'B forge made out of such material. It as found in grading for a ditob, and from the size of the trees growing over the Bpot must have been buried for at least 100 years, and may possibly be a relic of the early missionary days of California.

n. BOLtlELE MTNEEiLH.

With the exception of common salt whioh is of gen- eral distribution, and Stassfurt gait and its associ- ates, the balance of the useful minerals of this group all occur in arid regions where the climatic con- ditions favor the evaporation of the water which dis- solves the various ealts and holds them in euapensioD. Many of them are found in foreign countries where the price of labor is extraordinarily low, and from which ocean carriage is remarkably eheap, no that the products of the United States being found far inland, in thinly populated regions and often iu conaequenofl

M

USEFUL EAUrnr MWmALS.

fur from coETeuieiit Jines of transportation, oan with difficulty compete with the imported articlea. The eMoreHcecceB or tiruBts of borate of auda, carbonate of tioda aud salfc greatly itiHemble each other, but can be separated by the teste glveu iu the deBcriptiou of these minerals the preeeDce of GOFbonate of soda beiS: iitdi- cated by elferveeceiioe if oitiic acidbe added to a solu- tion of the incruatation. The compact maseivft deposits found underlying these iuorubtations may also be tested in the same meuner, and while under existing conditions of trade and trauBportation they may not be available for other than local couauinption, they may possibly supply a mineral whioh will render others ay&ilAble, just as cheap soda hi necessary to make quartz eand valuable for the produotion of glass.

BoBA.- — H. 2 — 2.5. G. 1.7. Luster vitreoue to resinous, sometimes earthy. Color white, sometimeB rayiah bluish or greenish. Streak hite. Traua- luoent to opaque, Bather brittle. Taste sweetish* alkaline. Imparts a clear green color to the flame. Boiling water dissolves double its weight of borax. (Dana.)

Borate of Lime, XJlemie or Hayesine. — H, liO. Q. 1.65. Color white. Tasteless. LooBe in texture, fibrous and silky, usually in rounded maases.

Crystallized borax (or borate of Boda) is found in the mud of certain lakes both in California and Asia, but the great bulk is produced from the borate marahea of Nevada and California, of which the general character is well described in the Geological Survey reports of 1883. borate fields are situ- uted in the extensive salines known as Teel's marshy lihodea's marsh, the Columbus marah and Fish Lake Valley, all in the southtasterly part of Esmeralda County. These salines consist of oval-shaped alkali flats occupying the centers of imiuBnee basins and cover from 10,000 to 20,000 acres each. These basins are surtouuded for the most part by a broad margin

2oS

PnOSPEGTIIfG AND VAL UINQ MINES.

of saga plains 'whicli rise gradually to the base of the liilla and motiTitainB wliich inclose them on every band- They have no outleta, and, receiving the drainage of the country around, retain eveirytbiiig broutiht into tliem, including the borates snd salts of vHriouB kicda. From midBummer till late in the Bpriui;, tvheu the anow commeneea to melt on the mountains, thege aaliniferouB landB are, aR a general thiugr, apt to be dry, only Rhallo-w lakes occupying sometimes their points of greatest depvesBion. At other seasona of the year portions of them are covered with water to the depth of a foot or two. Heavy rains, though thcueseldoiu occur in tbeBeregiona, con- vert these alkali dats into bede of tenacious mud, even B slight sfaower rendering their passage by teama dif- Cult for the time boiDg. Water can be obtaioed on these salines almost anywhere by digging from 2 or 3 to 10 or 15 ft. below the anrface. It is generally brackish, however, often so much so as to bs scarcely fit for drinking. By digging to much greater depths good "water is obtained a Bhoii: distance back frona the edge of the tnareh. Over Urge sections of these flats exist deposits of common salt, carbonate of soda, and borax. This latter mineral does not, however occur here, as at Clear Lake in Culiforuia, in the shape of compact, eemiopaque crystals imbedded in mud, but generally in the form of borate of lime or soda. The former is found at many spots imbedded in these marshes from 1 to 4 ft. below the surface. It crystal- lizes in long silky fibers which gather into balls from an eighth of an inch to 2 or 3 in. in diameter. Theee globular masses have the luster of white satin, and when dug up readily separate from the inclosing earth. The borate of goda mixed with aand and other impurities accumulates on the surface in the shape of a dark-colored incrustation an inch or two thick. This ci'ust when dry, being Lard and brittle, can be easily detached from the moister ground beneath and broken into frogmeniB*"

While Nevada and California are the oDly produc- ing States in Nortli America, there are eitensive deposits in Europe, India, Peru and Asiatic Turkey, and conipetition has reduoed the price from the old standard of 25 or 30 c, per lb. to a very low figure tl]© reduction baying, however, opened up new avenufia of use.

The leading uses of boras are iti welding (for which the greater part ia consumed in iron aud steel mauu- facture); in refiaiug metals as a crucible flux; iu enamelling i by pacters, in preserving naegt; and as a detergent for household purposes.

Carbokate of Soda oit Tsona. — H, %5 — 3,0, G. 210. Luster vitreous, gliatening. Color gray ot yellowish white. Translucent. Taste alkalioe. Not altered by exposure to a dry atmosphere. (Dana.) Soluble in water aud eServesces with acids, Trona 19 another of the minerals occurring as the result of the evaporation of water in dry inlaud basins without <iramagG outlets. The following description of one 6uah deposit will convey a good idea of them all :

"Thia mineral abounds throughout most parts of the Great Basin, the exteQaive alkali Hats which form a feature of that region constitnting the principal sites these deposits, which occur usually in the form of an efflorescence au inch or two thick on the surface, "but Bometimea in strata afoot or more thick imbedded in the earthy and separated from each other by thin seams of clay. When found in the form of a thin incrustation on the surface it is never pure, being always admixed with salt, borax, lime, magneaia and other minsrak. The heavier deposits are comx>ara- tively free from foreign matter, carrying generally about 0% carbonate of soda. One of the most re- markable repoBitories of this mineral known consists of a oircular hadiu, the bed of a former lake situated on the southerly margin of the Forty-mile desert, Churchill County, Nev- This basin, vyhich covers

254 pnosPECTiira anb yaluinq

&D area of 10 or 12 ncres, is depressed 60 ft. bslow the cotonaon level of tbe country adjacent- Its bottom, uauftlly dry, though iu, wet seBsoDa oovered with b few itiches of water, is composed of a corufaut jnass of tbe carbonate of Boda so hard that it has to be broten out with crowbars, and ao pure that it obd for many pur- poses be used to advantnie in its natural state. This fiubatance occurs here in layers about 1 foot thick, eeparated from each other by thin aeamB of clay. Xiarge quantities of the crude material are extracted every year." This deposit hns been worked over an area of several acres to a depth of 10 or 13 ft. without Bhowiug any signs of exbaustion. A portion of the product from the above locality ia used in the working of the neigbborinf silver ores, hut the greater portion is refined and sold for other purposes soda being very exteuBiively employed both in the arts and manufac- tiirea.

NiTKATE OF Potash, Niter oe Saltpeter. — H. 2.0. G. 1.9. Luater vifereouB. Streak and color white. Sabtrangparent. Brittle. Taste saline and cooling. Deflagmtoa vividly on burning eoals, and detonates whea loised with combustible substances. (Dana.) Dissolves easily in water and is Bot altered by expo- sure. Colors the flame violet when burned- It occura as au efEorescence on the surface or in the surface stratum of the soil in many parts of the world, but especially to a great extent in tbe valley of tbe Ganges and other parts of India, aa well as in Spain, Egypt and Persia, It is also obtained in a semi-artificial manner in nitaries or saltpeter planliations. These oonsist of heaps of decomposing animal matter, tniied with lime, ashes, road scrapings and other rubbish, covered over from rain, and from time to time damped with the runnings from stables and other urine. Such heaps develop within them small proportions of the salt, atid other nitrates, and are in effect artificial imitations of the saltpeter -bearing soil of India.

USEFUL EAitrnr 2rmEnALS. 355

Niter requires for its formation dry air and long: periods without rftia, anrl is in'oilmied most abun- dantly during hot weather suceeerling rain. The potash comeB mainly from the debris of feldapathia roaks in the soil. (See chapter ou rocks for the per- centogs of potash in various kinds of rocks.) It also forms abundantly on the walls of Gaverua and in tho loose earth floors of the same, which abound in th.e limestones of the Mississippi Yaliey in Kentucky and Tennessee. It is now prepared artificially from Chili- Baltpfiter and the German chloride of potash, by mutual decomposition, producing chloride of sodium or oozomon salt and nitrate of potaeb, or saltpeter, and this product has largely supplanted the native article, being a much superior material.

Iniiia furnishes the bulk of the imipoited niter.

Nitrate of Soda or Ceili -saltpeter. — H, 1-5 — 2.0. G. 2.0 — 2.3. Luster Titreous. Color "white; also reddish brown, gray and lemon-yellow. Trans- parent. Bather seetile instead of brittle. Taste cool- ing. Deflagrates Tvitb less violonoe than niter and colors the flame yellow ; also absorbs water on ex- posure to moisture and deliquteee'PB. (Dana.)

Cbili-aaltpeter occurB on exceedingly dry and arid plains in North and South America chiefly. In South America in the district of Tarapaca, Northern Chili, the dry pampas for 40 leagues, at a height of 3>300 ft. above the sea, Js covered with beds of this salt several feet in thiokness, along with gypsum, common salt sjid glauber salt with remains of recent shells indicating' the former presence of the sea. The arid plains of the Great American baain present almost identical condi- tions aa regards altitude, climate and rainfall (on the Nevada deserts only about 4 in. annually), and as might have been expected, this mineraS is found on the 40-miIe desert near Lovelock's Sttition, cryHtallized in the crevices of rocks and imbedded in the earth ffom 2 to 30 in. belo the surface. Ita oocurrenoe ia

35G PROSPECTm& AKD VALVnTG MINES,

also reported in a similar country near Calico, San Eerjiardino County, ChI. ; aud iii the soutlieru part of New Mexico, neat tbe Cbibunbtia lijie, tLe mineral is eaid to be deposited by Bpringa Id considerable quan- tity.

Nitrate of eoda is used exteuaivelx in the pro- ductiou of nitric acid fiiid saltpeter or nitrate of potaeb, tlje latter product entering into tbe compoei- tion of gunpowder-

Salt iu Bufiiciently well known to be diBtinguiebed from other similHr njjiierals, when in comparatively pure condition, by its taste alone, Eock salt occurs as imiuense beds formed by the evaporation of sea 'water> asBOciated with deposits of gypsum and other marine products. Percolating watera diaaolve these accuma- Jatioua aud supply the brines for the salt wells of Michigan, New York and other Eaetern States, which vary in dejitb from a few up to 1,000 ft., the average depth iu Michigan bein 882 ft.; in New York, 322; Ohio, 1*32; Pennsylvania, S83; and Virginia, 1,042 ft. The shallowest wells are in Utah, Texs and Kaneaa. Some brines are obtained not from beds of pure rock salt, but from strata of salt-bearing rocks Buch as sandstone, shale, etc. The brines from these wells are evaporated by artificial heat. In California, solar heat is extensively need in the neighborhood of San Francisco in the evaporation of sea watsr; while in Nevada salt is abundant in all the interior baains either as beds of rock Bait, asincrustationa on the sur- face, which are renewed as often as they are removed, and that so rapidly as to afford several crops annunlly, or as massive deposits, covered with slight deposits of sand or clay.

Sulphate of Soda.— H. 2.0—3.0. G. 2.6. Luster vitreous. Color white to brown. Translucent. Wholly Boluble in water. The occurrence is very similar to that of oarbonate of soda just described, the material beiug found extensively in lakes and beds iu

USEFUL JSAnmi MINERALS, 257

the States of Wyoming and Oolorado, and in smaller quantities in New Mexico. Well kjiown localities are the iake near Independence Book and the lake seven miles froin St, Maty 'e station, both in the Sweetwater valley; and Burdaairs Lake near Morrison in Colo- rudo. While outwai'dly appearing much the same, analysis develops the occuireuca in the depoaits of car- bonate of soda and common salt, in varying propor- tions, aa Tvell as various impurities ench an silica, linie and magnesia. Available in the manufacture of gt>ds glass and gunpowder.

m. LIQUID.

Fethqiedm. — Orude petroleum varies considerably in compoBition and density the latter varying from 0.6O to 0.80, forming the ao-called light and heavy oils. The oils give proportionateb' niore illumi- nating oil (kerosene); the hearvy more lubricating oil and residue. It is a hydroourbuu. standing inter- mediate in the series raugiu between tbe aaphaltum group of minerals at one end to the lightest naphthas at the other. Its exact origin is iu dispute, but is probably the decay of animal and vegetable substances under peculiar cooditions. It is usually dark green- ish brown in color, and m easily recognizable by its peculiar fetid odor. Its iollammability varies and is not alwa.v;s a reliable test as some specimens (of the lieavy or impure varieties) do noi ignite very readily. In the United States the light oils are found mainly in the eastern fields; from Ohio westward the oile are usually of the heavy variety. It occurs in porous sedimentary -Tocks of all kinds, as in sandstones, shales and some limestones; and iu point of geologic age all the way hrom the Silurian to tbe most recent. At the surface it appears as springs, pools and as a scum fioating upon the water. The surface prospecting conaista merely in

e; streams showing such oil films up to the F the petroleum spring or oil-bearing rook

a

r

'ZbS

PnOmCTLi} AND VALUINO MfMES.

outcrop. EoriogB for ail in depth ore generally di- rected in aocordanoe with tlie resulta found in exiatiDg wells of the neighborhood; though Bometimea bore holes are put down in localities far from any previouflly sunk wella where geologic reasoning shows the proba- bility of the presenoe underground of oil-bearbe strata which havs been proTei3 elsewhere, Borino; for oil is a special trade, baaed partly upon theoretical and geological eonBiderationa but more espeoially upon local experience.

IV. — GASEona. Natubax Gas also is a hydrocarbon, something like the "marsh gas" which sometimes rises from swampa, and also related to the "fire damp" of coal miries. It is colorless and odorless and is lighter than ordinary illuminatinsti: gas. Ita discoTery in a new locality usually resultB from accidental ignition; in regions where it is already known to exist borings for it are put down in accordance with the indications given by earlier gas wells, or to strike a stxatunj which has been gaB-beariug eUewbexe*

—J

The literature of coal is go exteusivB and complete, and coal miaiDg is so esfisntiHlly a business in itself, tLat in a work iuteudad cbieilyfor the use of thepros- pector for orea a long aocouut of coal would be useless aud out of fkco. This chapter will therefore be de- voted to the preseiitatiou of onl>' those poiuts which msky be aeiTiceable te the proapector who may ooma ttcroHS outcropB of coal while seaichicg for other minerals, so that he may be able to e&timate their value as aids in the reduction of metallic ores.

Origin. — The general origin of all coal beds is the same. MasBes of vegetatiou'were laid do\\'n in "nrater in a horizontal position, or neai'ly po; saxd then, ow- ing to geological changes, covered up nd buried by the rocks we now find above them, undergoing in process of time, thj"ouy:h pressure and heat, certain chemical changes, which, according to the period of time which haa elap&ud eince their foimatioD, have been more or less esttinaive; so that to-day we recog- nize several varieties, diatinguiBhed chiefly by their percentages of carbon and volatile matter, imparting to tiiem different aualities, The character of the rocks on which bedsjof salt, gypauiUj iron ore, etc., are deposited is purely accidental and unimportant but in the oase of coal the wide mLi'hes demanded a reten-

S60

PEOSPEm

Tud Valuing Mines.

tiye bottom to prevent drainage, and we cqneequently UKUflUy find a floor of clay, often fire elayj without which we oaunot iniagiue thn formation of sucl: euormouB accuiuulBtioiiB of vegetable matter, which before coEupreBsioD reduced them to their preagnt cod- dition must have had a thicknese from ten to twenty times that which they iiow exhibit- The edges of coal deposits are likely to be iai-gely contaminated with sand and clay or other waste matter; and it is easy to aee if the deposit be of small area, how this wortLleas margin may form a muoh larger proportion of the whole bed than in those of greater estent, as in th eaBo of coal wo must picture to oureelvea immenee level Tnarahy tracts, covered with a dense, luxuriaiit vegetatioQ which would certainly intercept any wind- blown debria before it had traveled far from the margins of the swamp, or would entangle in its roots the sediment brought down by Btreams, the velocity of whose currents would be promptly checked, and cou sequently they would drop their burden.

CoKPosTTioN.- — As a general proposition the percent- age of carbon is ereetest in those coals which are the oldest geologioalJy. Coal contains a certain amount of "fixed" carbon, or that which remains after coking, and also a certain amount of carbon in oodj- bination with hydrogen, oxygen and nitrogen, forming the volatile portion; the remainder is earthy matter (forming ash) and moisture. The following table, from Andre's ''Practical Treatise 034 Coal Mining" (which niay be cousuUed for all details), je very in- structive, showing that with age in the sense of geo- logic time. Goal loses the gaseous eiementfi, particularly oxygen and nitrogen, coneequently containing a larger percentage of oarbon, and steadily increasing in Specific gravity. An important exception ia found in the case of comparatively recent coals which have been heated and altered by the proximity (not actual contact) of igneous dikes or overHows producing the

Coal.

S61

some effect a& age. Colorado and other anthraoites are examples. The perceutuges are calculated irre- ppectiTe of ash aud moisture.

Cojhpahison 01* Caebosaceous Substances.

Subatuioe.

Wood— mean i>t 19 bands

Feat— mQQ of l$Bamp]eB' r..<

Camel cflei,,,.,.,,,,,..,

BlLuniinous coul— mean of .3 dJTi-

BJatiH .-.,.-

SiaiiilL-bitnnilnauiicoaJ— mean.

An(.hTacite coal— mean , , . .

Specific Gravity.

Per. CoJit l.SG

l.ffT 1.6fl

CaFlwn:-

Per C&nt, 59,30

fa. a:

Im.07

BS.17 IJl.UI OS. 50

gen.

Per Cen fi.25

5.ia

E.Sl 4.TB 3.7S

OxyRCQ

and Nitrogea.

Pur Cent, 44. T5 34. la SiI.4B

3.Ts

CLABaincATioN, — The claesification and names of coal fire based od the foregoing percentageH. A portion of the gases are combined to form "water, while the re- maiuder of the gases are oambined with a portion of the carbon in the form of "volatile matter, leaving a balance of carbon, which is known as the *'tixed" car- bon, and la that portion which is left &n eoke when the volatile matter has been extracted by distillation. The varying proportions of these materials render the different kinds of coal suitable for different purposes. Water in all case is a detriment to the coal, as it must be driven off in tbe form of steam at the expense of a portion of the carbon, which is thus lost for heating purposes.

The following cSassifcation of coals is taken from Andre aud is based on tbe amount of coke produced by diBtillation. The **Goke" in this case does not mean oommercial coke, but the residue left in labora- tory tests. Neither anthracite at one extreme nor lignite at the other make true Gok.

263 Prospecting And Yaluinq Mines.

CLASSIFICATION OF nOALS.

Nttme of Coal.

Coke, Per Cent

AntliraciCe

8emi-bit:uuiiDoua.,..,.p B8-8a

HtuininfuiH—

1 . (J Itrar- OurrilD ,, -74

8, FliuiitUiT 74-JtSa

3. Biiioky or fuliEiuous. 6B1

4, Oaa caal SO-dG

JJguite or bro>m coal,. K)

VoiiLtilt)

Matter.

Pur CeDt.

S-13

26-3S Bo

OUaracter of Cota.

Brittle and pordeiy, Brittle and poirdery.

Gtood. Poroua, friahla. Soft, powdei?-

PisTiNGursmNQ Chabactebs of CoAia. — AnthracUe — gtructuro la perfectly LoniogeDeouB, its density grentfji' tbiin tbat of other kiud uf coal, and it has a more completely mineralized appearance. Its color is a jet black, itb a sotaewlbat vitreous luster, often ex- hibiting a powerful play of colors. It does not (easily) soil the fiogerB when handled, beiug very hard and frm. In tlhe harder examples, tbe fracture is distinctly conchoidal, but wheu of a more tender character it frequently breaks into email cubical lumps. Anthracite burna wilh a feeble flame, blue when tbe supply of oxygen ia insufScient, and often deurepitates much in burning. It ignites u'itb difS- cuUj', and is slowly oonisumed, but when in a stitte of perfect eoaibustion it evolves intense heat. Thb quality of hardness possea&ed by Qutbracite enables it to be transported from i>laca to place ivithout injury, Tvhile that of svolving great heat without smoke rendere H peculiarly suitable for many purpoaea, aa in the generation of steam, and employment in distil' leriea brewerise, or in lime or briak kilns. In America it ia largely used for domestic purposes; also for steammaking on naval vessels at timee, and iu citiaa where 'anti-amoke' ordinances prohibit tbe uae of bituminoua.

Sevn-mdhraoite ia a term sometimes used to indi- cate a grade between strictly anthracite and seml- bitumiuous.

Coal,

Semi'-hituminous Coal occura next above the anthra- citaa in geological oidev. Occupying a, higher poai- tioD, it has been less espoaed to the action of heataDd other metamorpliic fltencies, and liaa coiiaequeDtly detained a larger proportion of tts volatile matter. Between tbe aQtliracitous und the aeuii-bitumhioua classeB, however, tbe line of division is purely arbi- trary, since from anthrficits to cannel there is every grade of compoeition. Its color is usually a dull black atid its fructure BubcouuLoidal. It frequently exhibits a peculiar fibrous structure, pasaing into a retuarkable toothed arraugement of the particles, called '*coue-in-coue" or crystallised coal. It burns with a slightly more abundant flame than corIb of the anthracitoua olaea, and evolves more atnoke, but not in denae volumea. It poaseasea tbe dry cbdrocter of the latter clsasj and from ita freedom from a liability to cake together, it in sometitnea called "free-biirn- ing," and **steam coal."

Biiiiminoiis Coal (Clear-burning 1).— "The varic' ties of tbe clear-bumiTig diviaioD are tbe pooreat in volatile matter. They are similar in testure to those of tbe preceding cIbbe, but generslly of a duller tiiater. They are very teJider, and break M-ith an even or au irregular fracture, and in consequence of the very per- fect development of the cleat* have always a tendency to break up itito amall oubicnl luwpa. These coals kindle with difficult.;*, and burn away slowly with a short, clear, bluish llanje, and very little sruoke. "When reduced to a powder and heated in a eloae Teasel they fuae and agglomerate into a dense and strongly coherent coke, a property* which renders them extremely valuable for manufacturing purposes. Both in quality and quantity the coke obtained from tbe clearburning coals is superior to that obtained ftom any of the more bituminouB varieties."

*UlettL IB iliv systL'iJi orpairdile-l joisu ac right angles to ita "DeddUig ot

£64

PH08PEVTmO AND YALUmQ MIMES.

Flaming Coal (BitumixiouB 2). — "The coals of this cluea are richer in volatile matters tbau the fure- goin, a circumftaiioe to vi'bicb they owe their Gbai- Bcteriatio Hamlng quality. Their structure is dis- tinctly lamiDat&d, &nt\ their color black and glosay. "When reduced to powder, hoiveirer, their color is a dark brown. They kindle without difficulty, and burn away somewhat rapidly witb a long white Same. Coals of this clas become partially fused wbeu strongly heated, and while in a fused state swell into a epoDgy masa, g;iving oS bubbles of gas, which bume with a bright tiame. This property of agglutinating in tbfi fire allows the email coal to be bua-ned which would otherwise be uselesB, or to be converted into eoke, of which it produces an excellent qiaality. To this property, also, these coals oive the name of 'cak- ing' ooal, which has been applied to it in comniOD with Horae other varieties of the sums Glass."

Fuliginoua Coal (Bituminous 3) "contain a Tery large proportion of volatile matter. Hence they kiudle readily, and burn away rapidly with a long yellow emoky flame. They are somewhat bard and strong, and their fracture is rather abaly. Coals of this character fuse in the tire Ute the flamine varieties but they do not agglomerate or cake into so compact a mais. The gas obtained from tbem is abundant and of B high illuminating power, but the coke obtained from this division ia friable and porouSf and unfit for poauy purpogee. " #

Gas Coal (Bituminous 4), — "All of the foregoing coaia occtti' in the so-called Carboniferoue period, but some of the preiiit section are found in beds of later geological times. The.i' are diBtinguished by the very large proportion of volatile matter which they eon- tairij and to this circumstance it ia due that they do not cake when heated. Experience has shown that coal beoomes caking when the proportion of carbon reaches 80%, and that of the hj'drogen descends below

Coal.

-/Q -, on the other haad, %vheii tbe proportion of hydrogeu becomeH very small and that of the carbon large, iis ia fihd autbracites, tbe eame noD-caliiig qual- ities result. The gaaeous coals are of a browalBb oolor auU of a dull liieter. "When redueed to powder tbey are quite browD. They are generally hard, compact and strong; their fracture ia even to coachoidal. Coals of this class kindle even mora readily tban the fuliginous varieties, and they burn ftivay rapidly with a long flame. The coke obtained from coals of this class is of a soft and pulverulent or powdery oharaoter aud useless for oommercial pur- poses."

Cannd Coal 'naturally falls under the head of a aeona ooa), though differing nnucb in appearance. It Ib a very hard compact ooal, of a black or browniah. black color, someEiimes glossy, but more frequently dull in luster. It doss not soil tbe iin:ger5 when handled, and it ia capable of taking a high polish. It breaks with a flat conchoidal fracture, and is distin- guished froro ordinary coals by the abatjuce of a lamiimted structure. This is a mark of its faigheat perfactioUj for when it comes earthy and impure the laminated struct are is developed. It kindles very readily, and burns away in the hand with a very abundant white flame. It is now employed altnosb esoluaively (escept for grate firea) for gaa making, for which purpose it corqmaads a high price. Sanmg of canuel oeour iu certain districts with ordinary coal, and often form tbe upper portion of a seam of biturai- ttous coal, and osoaionally of a bed of black-band ironstone." The splint coal of West Virginia and other States somewhat resembles oannel in appearance and [iialities, but is higher in the scale of lijced carbon*

Lignite or Brown Goal "occurs in the more recent geological formations. Tbe processes of njineraliza- tion having been leas completely effected than in the older ooals, tbey exhibit their vegetable structure

566 pnospECTima and valuing mines.

more completely, and a9 an effact of the same causa they retaiu a much larger pruportion of tbe volatik mattera. In colnr thay vary from brown to pitch black. Thoir luster ia generally dull, but Bometimea reainouft] the fracture ia various. They burn readily witli a dull ttame eniittiag mucli smoke, aud ed uu- pleasimt odor. lu couequence of the small propor- tiou of carbon aud the large quantity of watiar whicla tbey contain, the brown ooals do not possess great heating power. They are lariely developed in tbe T?estarn States of America. On accouut of the lare amotint of water they 'slack' into small fragments when espoaedto the air and sun, th large blocka soon showing a muUitude of craoks. "

iMFcaiTiBa IN O0A.L. — In all the foregoing remarks tbe coal ia supposed to be free from impuritiea. but as a matter of fantthis is seldom tbe case. ''Tha iiupuri- iwa may be classed as cseencidl aod aceiduntaJ] the former being those which entered into the corapositioa of the vegetable substaucea from which tbe coal waa formed, and the Litter those which have been inter- mixed with these BLibataneeB. The esseutial impurities consist of silica, alumina, lime, magnesia anil oxida of iron, to which may bo added water. Tha accidental impunties may consist of any substance other than tbe elements mentioned. Some of these have been in troduced by tb& iudltratiou of water holding tbe aub- stanoea iu solution. In general tbe accidental impuri- tiea consist of earthy matters, which were probably deposited from water flowing among tbe coal vegeta- tion, or blown thither by the winds. The quaatity of earthy impuiitiea present in any given sample of coal is estimated by weighing tbe ash after ooinbuilion. AVben the weight of the ash so left does not exceed £% of that of the coal, tbe latter is considered very pure. Above that proportion it begins to lose iu quality and becomes bard and sbaly in structure,

"A common impurity is iron pyrite, or sulphuret of

iJ

iron, a aubatnnce known to coal miners as 'brasaea/ Pyrite occurs soutotimeH an s, Uei>osit iillint tlie cirtks aDc] fissures in coal; soiuetiiiies as tbiu bed&. It is not infrequently njet with running with u lino of part- ing, or ifc occurs aw crystala diBserainated tLroughout the mass ; and more often s.& minute particles imper- ceptible to the naked eye. The preaGBce of iron pyrite detrftiits fTToatly from the value of coal by rendering it nnauitable for many important purpoees. Coal con- taining this mineral is totally unfit for [iron and steel] toetidlurgkiiil purposes [though available for other jaetallurgical uees. as in roasting and Binelting certain Tuetals], and it cannot be burned anywhere in contact with iron without serious injury to the latter. Hence it cannot he einployed for the generation of ateam, aa its corroding action would rapidly destroy the tire- grating and the lower plates of the bailer. Moreover pyrite ia decomposed by moiBture and converted into a sulphate, and tb& expansion which takes place dur- ing the process tends to break the coal into -very small lumps and even to powder. This decomposition is often accaiijpauied by great heat aud epontajjeoue combustion ia not infreiuently occasioned thereby. Heaps of brassy small coal and rubbish lying &s refuse on tbe pit bank often take lire from this cause in wet weather, and, whinh is of far more dieastroua conse- quence, the exposed coal in the workings will aome- timee become ignited."

While no ooal is free from impurities, the variation ia great both as to the amouiit of &nh left after burn- ing and of water. From tbe nature of the origin of coal, as Las been already seen, there must be a thin edge to the bed entirely round its circumference, and this will naturally contain a larger percentage of im- purities than the central masaj where they may be Scattered thrnngli the entire thickness of the seam or Consist of thin alternate Iftyers. Sometimea on*i or laore of these layers will extend over a large area and

2G8 Probpecting And Valuing Mines.

frequently a&Bist matei-ially in ruining tte coal. In BHcL cases tLa upper Beam may Lsre quite a different cbAracter to the lo'u'et' one and may be zuiDcd sepa- rately.

Test fok Coking Qualities. — Some coals -which appear to contain the rtquiBite iTigredieots to make good eoke refuse to coke except under particular treatment, And only a series of aoalyses, followed by Tvorking teets, can determine the ultimnte Tslue of a field, or to what purpose the product tnay te best adapted; but the prospector may readily ascertain for himaelf by the fire, whether his find comes within the coking series by the following raeana; Take a clfty pipe with a morlerotely long stem; fill tha bowl with clean powdered coal, and then carefully lute, or stop the top with stiff, well-worked clay. It is not advisable to fill the bowl too full, as if the coal ebould prove to coke, it will swell od heating, and raiao the clay cap, admitting air, and the experiment will be a failure, aa the coal will take fire. "When pre- pared, place the bowl of the pipe in the fire, beating it gently at fir&t to dry the clay without cracking, and then more rapidly to a white heat. Smoke and gas will be given off (through the stem), which will burn freely being made up of tho volatile matter, water and sulphur. When this ceases the operation is com- plete. Take the pipe fi'om the fire, and if the coal will coke, the bowl will be found to contain a solid mass of ccte of a bright dark grey color, hard and compact if good; but easily crumbling to powder if of poor quality. If the luting or stopper of clay has cracked it may be partially burned up, but a few ex- periments will easily give the requisite skil! to make the test. A large portion (practically all) of the ash, of course, goes into the coke.

The ash is determined by weighing the earthy matter left after burning a definite weight of dry coal in the open air (by which the carbon as well aa the

Coal.

volatile nmtter ig conQiinied), and calouIatiBg the per- centage. Analysis alone can determine thU accu- rately and fui'Qisb the information whether it is a high &r low grade coal, in case it refuses to coke.

CoMnEBciAL Vai-ue, — Tho proapector's interest in a coal diacoTfery centers in the question T\'liether it "will became a buaiuess Buccess on development. Thia depends on the nutuherj, thiobneas and dip of the workable beds; on an abundant supply of clieap labor, to keep tbe coat of miring, sorting and washing at a low figure; cheap transportation by laud or water; and freedom from competition with coals of its own class, thus filling a vacant place in the market. Many or all of these items maybe largely modified if the coal is found in a region otherwise largely devoid of fuel, &B many of our interior mining districtB, in which the price might be greatly ftnhanced, and the product yet have a ready sale; but the conditions be- come emphasized, eapecially as regards coal for domes- tic purposes, in densely wooded districts like western "Washington.

But with all conditions apparently favorable, the exploration of the field may result in failure, from excessive and unexpected "faulting" of tbe coal largely increasing the coat of working; by the intrusion of eruptive rocks into the coal seams, destroying the ooal; by a change iu tbe character uf the coal; by the thinning out of the beds; or tbe opening of other mines better located with regard to some item which gives them aa advautaije iu the market,

PRosPECTrsQ.- — There ia not snueh to be said on this subject. The first discovery ia likely to be purely ac- cidental, hut wheu made a few simplo rules will asiist in tracing tbe outcrop. The firat thing is to get a good knowledge of the rocks between which the coal found and their relation to other rocks above and below them, keeping a sharp lookout while doiug this for aay fossils such as ahella or plants. After acquiring

Prospsotinq And Valuing Mines.

thiB JcDowledge, the search must be oonSned to tlie region oucupiQil by these floor and roof rocks, and the knowledge gnlned of tbe nssaciated rocks will tell the searclier in wliich direction be must look, if be acci- deatully bas wandered beyond tbu limits of the coal- beaript; series, becauacj from the way in which the beda were formed oriiaally, they are now found more or leaB parallel to the juuotioii of two different kinds of rock.

tf the Goiintry has been much tilted the outcrop may foUow quite a wavy line or eren apparently run in a Bemicircle, but having by the meaus just stated defined the limits of the area in which coal is likely to be found, the searoh may be continued by follow- ing up the ravines which cut this formation. la a densely wooded country this kind of exploration ia dicuU, but as the coal is softer than the rooks in which it ia found, there is usunlly a eharp break or drop in the bed of the rnvine at the point where the ttooi ci'uasGs, and ail auch placua ahoiild be curefuUy ecainiued- Beyond this the progpeutor must use bia own judgment.

As eoal eufEers from ©spoaure to the elements, it ia likely that the outcrop will be inferior to the coal found at a little depth below, but whenever the roof and floor become aolid and show no signs of decay, the coal there found may he taken aa a general, but very roiih, sample of the deposit.

Provided all the surroundings appear satiBfactor' a complete series of boring! should be made to prove tbo couditicn of the beds aa rejarda "faulting, " but at this point the work of the prospector ends and that of the engineer be gins.

Gbatel Mihxng or washiug is carried on to obtain plaaer gold, platinunij tis, diamouds and some other leas imiiortaiit Hubstimces, wLich are found during tlie tjearcL for the more "valuable ones. "When tbd water used ii] the pruceas is applied under pressure tbe term "bydiaulic miuiuij;" is applied to tbe operation.

Title depoBita operated upon may be glacial drift; the beds aud hilLsidea of luudern streaniB, \vbicb are geutjrally called "plaoerK," and the operation "plaoer miniui;" or the gravel aGcunnulated in tbe beds of ancient streams, long since dry, and not infrequently loL'atud bih on tho inouiltaili sides above all the pres- ent riverii, may be attacked by hydraulic methods, when not covered with a lava cap j or "drifted" by means of tunuele, in a manner similar to coal mining, when tbe cup of mountain za too hard to be removed economically, or the top gravel too poor to pay for wasbiDg or water too scant in supply or with too small a head or proSisure to admit of hydraulicking. The working of ordinary placers by ground sluices or by sluice bustja is so well nown thuit it is not Decea- eory here to enter into any details.

In Btudyiug graYf;! deposits we muai remember tbat tbe lawa fejoverning tbe operations of nature have been the same for aU time; that the forces have been the samei though they may have operated 'ith greater activity ; aud tbat any esplau&tiou of tbe phenomena which is not in strict accordance with these laws must

zn

PROSl'ECTINO AND VALUING MINES.

inevitflbty be erroneoua and defective. This caution is tlie more necessary as we Lave to deal largely in our explorations with thiDga that we cancot see and ean only baae our sunuiaeB as to their noDditJon on the lawa which we know to goTern the same circumstances in the world which is open to our inapection. Any jiropoaition which ie rn direct oppoeitioti to these laws ahould Lb laid aside pronoptly as worthless. The iraportaace of thia is especially apparent in (he open- ing of "drift" miuflB.

Obigin of Gravel Deposits. — Al! accumulations of gravel and sand have been made by the action of water, either as running streams or sea waves, or by ice as glaciers and icebergs, and result from the wear- ing away of rooks by the action of the air or rain or frost, or all three camhined. The nature of their con- tents must therefore depend on the character of the rocbu which have been destroyed ami the width, depth and velocity of the etreame which carried the material to its resting place, or the area over which ice sheets and glaciers or Boating; ice could carry its burden of soil and rocks before melting and Jepoaiting its load.

As we have seen in studying the tilling of mineral veins, the minerals are disseminated through a variety of rocke, and the presence of veins is not necessary ;, aa is so generally supfoaed, to "feed" the stream. Wbem a stream ceases to show gold in the bed on following it upward, it does not follow that there mufit toe a rich vein in that vicinity, for which we constantly find the miners searching; it may be simply an intimation that the upper limit of the gold-bearing rocks has been reached. We can indeed have good placer diggings in regions where well-defined vmus are scarce. If we once thoroughly realize this gBue:ral distribution of gold in certain belts of rock, the origin of gravel deposits carrying golti tin or platinum beoomes much more easily intelligible,

"WhcE) the rock is decomposed by the ordinary action

Gold &Hayel Deposits.

cit frost or air and rain, tbe defcatshed particlas fire oon- stAatly lesc6Eding by the steepest liD©, under the aGtion of gravity or water and this ia usually more or leas at right aiigles to the etrema iuto which thy finally find their way. During this desoent the par- ticles of gold siiSer but little abrasion, as their prog- reas is exoessively slow, and they undergo no sorting into BiBee, other than what would result from tho grejxter juomentum of the larger particles, causing them to travel further on a steep eicle hill wherd butt little surface water and rivulets acted; but if there woro much water coming dovn the aido hills, the TBTersei might occur, the larger gold particleB Te8i.sting more than the light flaky onea. On outering the vater their fate depeutia on the depth of water and the yelooity of the etream, If the latter is great the finer flaky par' tiolesj which even in still water descend to the bottom very slowly, will be awept away with the sand on their Beaward journey, only the heavier pieces reaching the bottom, where they will continue to sink into the river bed by their auperior weight as long aa the surface ia very soft or Hlightly agitated- The leas the Telocity, the smaller will be the amount thus swept away. In cases where the gold haB not heen luuch subject to the action of water for coutinuoua periods, it may retain its crystallized or angular form, and this is usually an indication of the vicinity of a vein, especially if por- tions of quartz are still attached to the epeimens. The smoothing and flattening of nuggets and graina of river gold is probably due to alare extent, if not alto- gether, to the impact of heavy rooks and the poHahing action of auud aud gravel as they are swept over it in the river bottom, just as such material polishes and wears away the angles of bowldera or aolid massea pro- jecting from the bottom of the stream. It does not aeeiQi probable that the coarse gold has ever traveled very far from the point where it first found lodgment in the river, but the very finest particles may be trans-

274 PROSPECTING Altl

ported many miles. Gold derived from the decay oj oitLer iron or arsenical pyrites taay bo so exceBsively line it will never fiud a lodgment on the bottom u]]til the sediment with which it is mixed reaches quieacont or perfectly tranquil watere.

liiVEii Deposits, — All rivers &nd etreama roay be compared to immecBe sluice boxes in which the heavier particles have been retained and tbe lighter ones washed away, while nature haa been carving out tho river basins with all the forces at her command, pre- senting for OUT final clean up the consents of an itomense mass of material so ijiexpreedbly poor in gold, platinum, tin, etc., tbat human efforbs fiould not have undertaken the task. Some idea of the extent of this concentration may be obtained when we remem- ber that we have absolute evidence that some of the river channela in California have been cut down fully 2,000 ft. below the aurfacs as it esistn to-day. In Bueb a valley with a width of 6,000 ft, from rim to rim, 6,000.000 cu- ft. of rock have bean removed (6,O0OX 2t,000-H2) to carve out one running foot of its length, and all that remains may be a deposit 400 ft. wide by an, average depth of 20 ft., or 8,000 cu. ft. to the running foot of the Talley, or in other words 222,222 cu, yds. have been concentrated down to about 300 in round numbers (say 740:1). If the value of this be ¥1 per yd. the original material would only have contained about one and a third mills in the same quantity ($0.00135).

During this process a portion of the finer gold hae been carried down the stream to flatter regions by the strength of the currei] t, bn t the coarser has been retained, probably not far from its soui'oe the extent of the deposit varyin; considerably with the character of the bottom of the channel, the bowlders in which act the part of riffles or lining in the artificial sluioe

box.

Modern Streams.— Id. the case of the modern mou]),<

Gold Ora Vel Dep0Sit3.

tain BtreamSj the Telocity and qunntity of water have been BO aclinsted to the amount of nji&terial brought down, that the buJt of tlie finer debrig or waste has been carried down to the vallBya below, leaving only te coarser grBTeL and bowlders in the bedti of the rnvines tilled iu Tvith a ceitniD percentage of fine jn&- teriid m the iufcevepacea, makiisj the deposits compar- atiTely ehiaUow and rich, and there does not ajipear to liave been much cany;e fronj time to time in the cou- ditious under which they were made.

AncieYil Eivers. — When we come to study the anoient or buried streftma, as they eiieted prior to the laat gieat outbreak of tavAs, iu which the deposits are sometimes 400 ft. thick or over, we shall tiiid evi- dences of great alterations in the flow of water from time to time, and the charactier and quantity of the material oarried by it iu BiispenBiou. If we trace the history of one of theHe old river channels, as rand by the records it contains within itself, construed by the laws of nature in operation to-day, as in the paat we shall get a clfiitrer tdea of their structure than in acsy other way and be better jjreparad to open theui for Buccesa- ful mining.

Bedrock; Uim; Grade. — The rock on which the gravel deposits lie is called the "bedrock " (ste pi. 10, figs. 1 to 6)3 and the point where the bedrock and jrraTel or lava are seen in contact on the surface the '*rim/' as in pi- 10, fig. 4, a,g; fig. 5, o.. The inclination of the bottom of the stream in the direction of its flow is known ae the "grade" of the channel. By com- parison with known mountain rtiuties, it will be seen that all fitroBma Lave steep grades near their sources, becoming flatter and flatter as they approach the low- land valleys.

Boitnm Oraveh. — The first stage was eiruilar to the conditions surrounding our' modern gtreams. The \i'6nring away of the bills was carried on comparatively slowly, the streams were of moderate velocity, carry-

276 Prospecting And Valuing Mines,

ing oS the waste and leaving the coarse gravel and gold in the river beds. Large quatitities of material brought ilown in flood time were gradually panned out during the drier seasons, as we know by the tbin laj'era of iron aand, euoh as we see cleaned up by the lap of the stream on our jjreseut river baukt and sea heachGB, leaving tbe eontained gold to enrich the bot- tom deposits. In this way the BO-called "bottom'' gravels which are tbe exact counterpart of the modern Xilaoert, were formed by the alternate flood deposits and alackwater panning. Tbeae bottom gravels are usually the only ones which will paj' for the slow prooesa of drifting ; and sometimes, when too poor for this method of working, tbe entire "top dirt" has to he removed, evtjn if it barely cover espeEteee.

I7ie Deep Beih\ — Tben commenced a change in the Burro tin dings. Tbe quantity of sediment sent do'wn had been bo great tliat tbe streams at the mouths of the jnountaiju valleys becsiiiie filled up and the sedi- ments began to accumulite in the valleys tbeniselves and from that time the material deposited assumed a fat grade, and the filling up of tbe bed of tbe stream proceeded at a rapid rate, creeping -upward as the lower portioua became mtire and more choked, until in some casea we find tbe thickness of these beds ruD- ning up into the Lundreda of feet. The gold in such material is naturally tine, and not having undergone the proce&s of concentration to such an extent as the bottom gravel is inucb less ia quautity for equal bulk of material; but there is no sharply defined fine be tween the two, although tbe depreciation takes place rupidly until the gunernl average value of the upper fine beds is raacbed. This results from tbe fact that there is to some extent a combination of both condi- tions at or ijear the point where tbe flat grade cf the valley met the steeper slope of the mountain streHm. As the valley filled uii the river channel naturally be- came wider, the sheet of water thinner and in couee-

Gold Gravel Deposits.

quence lees anil lesa able to carry any burden in aus- peusioQ, and it is easy to picture a wide sandy bottom with uhaugiQg ohaDOdls, bars and Btaguant pools ob- struoted by snaga aud log jams. All the conditions aj'e beautifully shown in the deep gravel workiugs at Sailor Piafc in Nevada County, Gal. PI. 12, fig. 7. shows a portioQ of the gravel banJc at this place, and the coustflQt chaiitjea of the channels can be read in the various deposits of saud and gravel lying udcod- formnbly on each other. The black uiarkB in tbia figure show the position of pieoes of petrified wood, which is found in enormous quantities in every con- ceivable form of petrifaction. Sometimes the trees are imbedded singly; at otbsr points they have ao QumuUted OQ bars and are massed together as we see them m moderu etreama after Hoods. lu the shallow paola, the falling leaves have aecumnlated in the ilne ailt or mud, bicb now splits in very thin layers, and reveals a wonderful variety of leaves, the imprinta of which are in aa esoelleiit atate of preservafeioQ.

That there were occasional periods of drought when the water was oomparativaly free of eedimeat, yet \vith a velouity aaQienb to piok up and remove the finer sand to a certain extent, is shown by the thin beds of fine gravel which can be seen on the faee of the bank, and which by their aiiperiorriohneaa indioats a certain amount of ooncentratiou, a3 in the bottom gravels. In a few cases these beds have become sLiMcienfily thick and enriched to pay for driftia, as in the case of tlia Breeoe & Wheeler mine in Oalifomia, of which a gen- eralized oroas aactioQ ia shown in pi. 11, fig. 2. The upper tunnel was run on auch a deposit ao cemented together by the iron whioh remained among the gravel, as a part of the concentrates, that it had to be crushed in a mill to save the gold. On pi. 10, £lga. 1, 3 and 3, the so-isalled top dirt is shown by c, the bot- tom dirt being indicated by the solid black at 9. Tho modern placer deposits are shown at e,e,fl.

2T8 PnOSPBCTING AND VALUING MllfSS.

Fipeclatf. — The besinniag of the third stage cotn- meaoes with tlie reaewad voloauic activity. The positioa of sand aad gravel aeased aad immeiise bedafl of olay, called by the ujinarg "pipeclay,** sometimes reaching a, tbickssa of 200 ft., 43 at Cherokee Flat iu Butte Oount/, were laid down. At other pointa we have depoaita of rounded bowlders lite cobbleatones and it ia not ualikely that these deposits were derived from the earlier outbreaks of the volcanoes, aacom paaied by exeeasive rainfall, whiah washed the ejected matter into the ravinee, the fiuer material, aa iu all other oases, being aarried furtbeat from its source. Moat of the bowlders ia ordiufiry plaoer gronud are* merely waterworu fragmenta of local rocka ; the large proportion of quartz bowlders beiag due to their hard- ness. Ibis certain, however, that immediately sueceed- iag thasB bowlders and clay, immense outbursts of lava poured into the river bottoms and filled tbem from bank to bank. A case where a bed of einter (volcanio ash) separates UDOoaformable gravel beds is shown in pL 12, fi.g. 6, where the sinter bed appears , to have been tilted after deposition.

Lava <7cy:j,— Some of the lava beds are over 100 ft, in thickness and form to-day ooQsplouous objects in the landscapeg of the gold regioua of Galiforuia, where they cap hillB called Habls mountains" from tlieir nearly level summits as een against tbesky and their precipitous sides. In pi. 10 figs. 1, 2 and 3, the pipe- clay is shown by b and the lava cap by n. With the formation of the lava cap the process of filling was completed. PL 10, flg. shows the order of succes* sion — bottom gravel, 7; fine gravel and sand, c; pipe- clay, h; lava, a. The dark shaded portion shows a cross seotion of a mountain wi£h its ravmes as they exist to-day. The dotted liuea vi,m, show the hills on either side of the valley as they existed during the process of filliug, and the horizontal dotted lines r,?,/, the continuation of the beds fl,&,c, before they were worn away. ' -

Gold Ora Vel Deposits.

3T9

Modern Forms. — The carving of the country to ita present form then began. The river waters on le&uin- ing their sway were diverted into new cbaiinelBt and in TaOBt oafies two Htreums wia formed out of the orig- inal one. When lava tiowg into b. conlaned chanoel Buch as a valley the unrface and sides of the stream in contact with the rock a, and especially the thinner edges, cool more rupidly than the central core, which, remaining in a plastic condition Is liable from the preasure behincl to break the upper ciust, ThJs ia oonse fluently piled up in the center of the flow in rugged masaea with a higher elevation than the sides. In this way there is formed a depression on each aide of the flow nest to the valley "wallg;, each of which be- comes a watercourse, indicated hy the arrows in 6g. 1. Owing to the euperior hardneea of the lava cutting away of the new channek took place largely at the expeusei of the rocks forming the walls of the valley. By degrees these were eaten away below the level of the under side of the lava, when the process went on more rapidly in the underlyiDg clay and gravel, which on being undermined allowed the lava to break off in vertical faces forming the characteristic bluffs of the gold regions. "While this process was going on large quantities of the finer gravel of the original deposits were carried down to lower regions, taking with it the finest of the gold, the course remaining behind, and new placers were form- ing. "We have evidence that there were two outburets of lava, producing iimilar results. In the lower val- leys the lava capa are entirely basaltic, but in the higher regions the first eruptions were either trachytio or rbyolitic. Both eruptions are welt ehown in Flumas County, BB in pi. 10, fig. 1. 'When, after the trachyte outburst, the cutting of the new valleys had proceeded to about half its ultimate extent the basalt ontbreak. occurred and invaded ome but not all of the streams. In this case the gravel oontaiiiB pebbles of the lava got*

tm

Psospegtikg And Valuing Mines.

ering the older channGl, a,b,c,fi, aloDg with the quartz gravel vbich ia cfaaracteristicof both, but the laTa cap is KU exceedingly hard, heavy, compaot, black iron- lilie baealt, vrhile the cap of the older cbanuels is a light-colored gray or reddish traohyte, much lighter and coarBor in grain than the baealt, and very bareh to the touch on a neAvly broken face. Being much 6ofter than the baealt and less liable to take columnar forme, it> seldom presents such coiispjcuous bluffs ob the basalt. In some cases the basalt lies directly on the gravel ; in others there is the usual bed of pipe- clay. If this m ftbeeut we may preenme that the region Vi'as near the source of the lava flow, and that the material forming the clay bed bad been washed down to the lowei- country or bad not been ejected in large quantitiea. The clay beds under the basalt at Cherokee Flat m the foothills of the Sacramento valley are very thick, while in Onion valley, near the summit of the Sierra Nevada, at an altitude of 6,000 ft., they are either very thin or absent. That the eruption of the basalt was later than the formation of the older gravel beds ia absolutely proved by the occurrence iu the Laporfce region, Plumas County, which is located on a trachyteooTered channel of great length and prominence, of a basalt cone overlying a bed of gravel, the pipe or neck of which was penetrated by one of the deep tunnels, and the gravel bed "drifted" all around it, some of the gravel being even eurronmled by thin sheets of lava at the outer circumference of the neck which formed the vent. At thia particular locality the trachyte cap had been eroded. The structure is shown in pi. 10, fig. 6, where a ia the gravel and b the Inva cone with its neck or pipe ascendinc throiigh the bed- rofik and gravel.

Since the basalt outburst, which svas of enormous ertent, covering hundreds or even thouBands of square milea in California, Oregon and Washington, there seemato have been no aerious volcanic diaturbance, and

Ora Vel Deposits,

le denuiiatioD went steadily on up to modetn times, leo.'iriug a mountain range in the case of encb dow, of which we Lave a plan in pi. 11, fig. 1, which repre- seuts two modern atreameijii, and the buried ancient riTer jS'f", with thoae portiona of its lateral streams which have not been worn away in the general denudu- tion. L represents the lava and pipeclay oappiui;; Q the gravely and the heavy black lineu that portion whieh is known as the bottom gravel and suitfibld for drifting. As the denudation has not progressed evenly, it may happen that the gravel at some points has not been exposed, and the lava apparently lies on the bedi'ock, as at U,

"Oversows." — In other places it may be exposed on one or both sides of the ridge, or the lava cap may have entirely disappeared, as at G, showing the gravel on the surface all the way across the dividing ridge. The richer bottom gravel found in tb© lateral branches of the stream will Naturally be exposed as at T, T. A common term for these exposures is an "overflow," aa though the gravel bad been squeezed out of the bill, but that this expresaioD is erroneous is shown from the fact that tha grade or incUotttion of the bedrock dips into the hill„ as shown in pi. 10, fig. 5, where a ia the so-oalled overflow and g the main channel to which it leads. The only exception to this rule is where a remnant of the head of one of these lateral branches is left on the other side of the modem ravine, which has out the lateral in two without removing the upper portion. Unless this lateral was a large stream, the gravel left will be only a small patch. If a large stream it may present all the features of the main chan- nel if it happened to be covered with lava (which does not necessarily follow).

iafira.s'.— We also fracLueutly hear miners spaak of two or more channeHs in the hill. Such a condition of things is aninatall probability the dividing of a stream into several braucheahein almost exclusively conlined

asa PHOPEGTiNG AND VALUrNq MfPffSS.

to tboBe portioBs wliich have a 0nt graiJe, and does not ocQur where tbe grades are Biiuli aa yve find Id mountain regions. "Wliafc doea occur is shown on the line OPf pi. 11, fig. 1, where if OP were a tunnel it would out two bodies of gravel, but they would be oaiy branches of the satQe Btrsain, the first one eneouQtered> if the tuunel started at 0, havinij; a steeper rude thuo the secjcmd, as lateral braachea of a river have almost universnlly heavier gradea thaD the main river. If there ia a suddtin expansion of the Lava nap, and a more than ordinary width between the rims, auch a propoai- tion is almost sure to be found beeeatb the surface. PI. lOj fig. 2, represents such a structure aa would be found on the line OP of p]. 11, ti, 1, where we have two gravel banka c,c, under one lava cap a. Without going' into further detail it may be said that all these features can he reproduced iu a model, thus proving the general accuracy of the theory of origin.

I'auUed Ancient Channels. — It is not to be expected in H country which haa been the seat of guob compara- tively recent volcanic activity that there will fae an absence of faults and dislncations in the channela. Un- fortunately these are numerous and often interfere with the auGcessful working of otherwise valuable property.

Three examples of such faulting are shown on pi. 11 in figs. 4, 5 and G, all taken from the mining re- gions of Plumas and Sierra counties, Cal- Figr. 4 showe the aitufttion at Graas Flat near Laporte. Here the fault Ali has out the channel acroas its general direc- tion, the left hand portion in the figure having beeu raised, ur the right hand portion depressed, as shown. The bedrock at e consequently acted as a dam, and backed up the water flowing down the bedrock, till it formed an underground reservoir P, the drftinat:o outlet of which near A was ho near the surface that grassy meadowa were formed at sustained by the perennial water in P; hence the name. It was impos- sible to work the submerged ground until a long and evpQUsive drain tunnel had been run

Gold &Ra Vel Deposits.

Pig, 5, pame plate, sho-s n fault tunning lengthwise of the channel in the pit at Laporte, ah being the dis- locatiaUj d the bedrock, c the gravel, and e gravel from the later aeries oJ gravela previously described, barren and almost entirely devoid of quartz bowlders. Such a fault ia not so detrimental to the working of the de- posit, aa it can be followed npstrem without interfer- ence; but in such a case as in fig, 6, where the dikes c,cc have broken through fltid dislocated the grravel g, the drifting operations on the bottom gravels, sfaowQ in black, beQame bo expensive that while the giavei waa rich the expense involved in hunting the continuation of the channel beyond each dike consumed all the profits.

Folded Gravel B<!:ds. — Inetead of sharp faulting, gravel beds sometimeB show evidence of diaturbauce in the shape of folds, either in smooth long sweeps or ia a complication of smaller waves (pi. 12, figs. 1 and 2). Folds are, like faults, often acoompanimenta of voloanie eruptioua, and the gravel may be dragged with the lava sheets.

HiLLaiDB Deposits, — These have the same origin as those just described and ara in fact in many cases, if not in all, only their lower portions, which, being at the time of the lava Hows below the level of the sea or interior lakes, or for other causes, escaped the lava cap which buried the upper portions of the streams. As the laud rose the streams began to cut down into theas deposits, Gonceiitrating the contained gold on the bars and riffles along their sides, which sustain a conataut renewal ad the rainfall washes the hinsides down into the river bottoms.

There is one class of hillside deposits, of local origin, in which part of the gold has, in descending, been con- centrated in poekets formed where favorable rock for- mations occur, as in the case of slates dipping into the hill. These pockets have since been covered over with eoii and debris, and some of the gold may have been

as4

FEOSrSCTTNQ AND VALUING MINES.

ciirrie*! out of tliem aod further ctown the hillside, KproacliDg out in faulike ehaxm. lu aeflrcLicg for such poclceta the prospector pans out aamples of dirt along the foot of the hill, noting: where pay or at least some yolii begins aiid ends; then runa a corresponding lina of pan testa parallel and higher up, marking the limits of the pay. If thia second line is, as is probable shorter, it \vill iudicnte a triatile near the apex of which the pocket is sought for by trenching.

Hea Bkacb Dej'OSITS. — These are mainly derived Irani ancient gravel beds, which are reconeentrated by being broker down by the impact of the waves, and sorted by the waves and tides. As these dflposits are Id GioBt cases the furthest removed frotn their original source, the contained gold is of the very finest char- aoter> and consequently the moat diflBciilt to save by mechanical appliances; these difScuItiea becoming steadily greater as the size of the particles of gold diminishes. If, however, the ocean were operating on solid rocks of auy of the various kinds which contain gold, there is no reason why we should not find depoaits of oonglomerate with coarse gold, gritdually fading out into finer mid finer sedimentB with finer and finer gold, aa the beds recede into deeper and deeper water, to which only the finer sediments would be carried by the refiux of the waves, or undertow. And fnrtber, if the coaat Hoe which ia being destroyed be gradually sink- in<r, as we know to he the case in niany localitieSr just aa it ia rising in oihera, we should have such a bed of conglomerates, consisting of the larger waterworn frag- ments, eitendins? over a lare area, both in breadth and length, friding out on its upper surface into the finer ond poorer material, and in some such way as thid the heds of gold-bearing congloraerates may have been formed. The destruction of the shore line would be more rapid and the deposits more extensive than in those cases where the coast is gradually rising, aa in thia instance the same material would be longer exposed

to tho abrading action of the waves the formation of Qonglomerutes ivould be leHB, ani} of &ne sediments more esteugive, and tJLie ijold particles would euflfer more abrasion and be reduced in aize.

In searahic for guld-beariug beach sands, these oi'e naturally to be looked for under blufft of gravel ttud conglomerate. A favorable tinie is after & strong %¥inLl blowing along the coast line, which maksy cross waves, advantageous for concentration. The best spots will usually be those marked by lilies aud patches of blat:k Baud, which are almost always coDcenirated wherever any gold is.

Besides the beach B&nds proper, gold-bearing Bands have been worked; oS-shore by dredging, on the <!oaet of New Zealand.

GiAciAL DEPoaiTs. — Under this head are included all those depoHits in which ice has played a port in their formation, and wb have atsequoutly evidences of more complicated action. Aa in all other deposits there must be, to start with, a belt of gold-bearing rocks to be removed, or the resulting maaa will be barren. Given suob a belt of rooks there ia no reason v!hy glacial depoBita should not contain gold, just as thue which have been derived from aerial eroaion, but we are likely to find a greater variety in the physical ap- pearance of the gold, either smooth or angular, aoarae or fine, because it has been released from the eontaiu- ing rocks by a variety of methods.

Glacierfj transport to the lower valleys, first, the rocks or bowldera which are detached by frost from the exposed bluffs which form their boundary walls; and aeoondly, the rounded bowlders and sediment which are formed by their grinding action on the rocks over which they travel- If they cross a belt of gold-beariug rooks they must discharge into the valleys the contents of these rooks, along with the remains of the rocka themselves, either in the stream which issues from their "foot/' or into the terminal moraine, if they

236 rnOSPEGTINO AJB VAl Um& MISES.

termiuate ou land ; or tLe oautents may be widely dig' jieriod by floatiu iue or icebergs if they terminate in tba wfter.

While luorainal deposits may be oneuited to min- ing Teiiture&j, the river deposits resulting from glacia- tiou may be worked by niiicbiuery suitable to the rs- teution of the excessively fine gold, which muetnece&- Barily be lost in the agitated waters of a sluice box.

Gbavel Mining.

What OonstUittes a Worfcaijle Gravel Proposition.- The elements which go to make a workable jiravel mine are ; 1, the amount, of and distribution of the gold itt the travel; 2, tUe widtlj, continuity, and extent of the deposit; 3, tba character of the bedrock; the depth of the hedrock iu relation to the neighboring rayines; 6, the grade of the channel or bedrock and freedom from faults; 6, the available dumping ground for the wagteiniUerifll ; 7, the character and amount of the water supply. While all theae elements enter iuto every working prepoitiouj they have widely varying values aoeordiiig to other coDditiqna.

Placer Mining. -Th] term is sometimes used to in- olnde all methoda of working placers or gravel depoaitB; i 1 19 here ap plied in the uan al an d more restricted senae, excluding hydraulic mining (which involves the use of water under pressure) and covering only those methods of gravel washing (mainly in recent pincers) in which the water depends for its working qualitiee simply on its quantity and the grade of the sluice boxes in which it in used. The altitude of the source of supply cuts no figure, except as Jt affects the grades od which the gravel can be washed, Ae tbia condition involves the handling of every pound of gravel by manual labor, or praotioally &o, it is only the richer nnd consequently the fihallQwer deposits which are available, such as the beds of ravinea, river-bars and the shallower adjacent

Gold Qra Vel Dsp0Sit8.

deposits. "When the former become too poor to work, the miner says he has lout tlie ithaune!. It is not always nieaut that tLer© is no JoUfer iiid jcatioii of gold, but its concentration i& not uutSiTient to wartatit hand- ling hy Buch alow njethods. For the '"pan" and the "rocker'* a very small quantity of water ujay be suffi- cient, and the amount ofniatoriiil handled daily is bo comparativoly Rmall that the tiueBtiou of dumping ground doee not trouble the miner, neither does the grade of the channel, nor disturbance by faulta, be- cause his apfiiiances are movable on short notice; and the same mity be said of the ''long torn" or sluice boi into which the gravel is shoveled when working on a HomewLat larger scale; but the depth and oLaracter of the bedrock may be all important, as it is on the bed- rock that the miner finds his chief reward. If he in unable to reach it on account of the inllus of water the cost of wing-damming the stream or pumping may eat up all the pro6ts, and after all the bedrock may be Buoh that it h;is not been able to retain the gold.

A perfectly Bmooth sluice box would permit all the gold to esoape, and to avoid this the bottom is either provided with riffles in the shape of alatfi, or paved with bowlders and sometimes with wooden blocks cut across the grain. All of these methods provide crevioea into which the gold drops as it ia swept through the boxes by the force of the water, and is thus prevented from escaping. The bedrock in a stream &cts in the same way. If perfectly smooth, as at E, pi. 12, fig. 3, it may be absolutely clesn, there being no obstruction to give Anything a retentive ho]d. A case of this kind occurred at GibsonviSle. Cab, where a long tunnel was run to open a pietie of ground lying between two minea which had paid haTuIsomely, only to find on reaching the channel a perfectly smooth bedrock and almost rerfectly barren. The most favorable condition ie a bedrock pitching dawn stream ns at A, in the Sjime diagram fio that nil the crevices are presented to the

Frosfecting And Valuing Mines.

impact of tbe deecending material. Iq eucb crevices tbe gold is literwlJy juimued iuto the rock, and it will uitiuaUy pa.y to miue from 6 in. to 1 ft. of its Burface along with the gravel, esrcciall.v if it be softer, as tbe miners nay, 'choosy." A Biiailarly trood bedrock ia ftn-med by the worn surfaces of linit;etoiie h and C, which bfcing eaten out into irregular holes act ag; per- fect riillba and 'JYe good residta as itt Sbaws Flat and Ooliirabifl, Cal, ; but less satiefactory returns are usually had from aluty rocks pitching up stream as at D, especially if the rocks be hard, as objects slip readily over such surfaces. Tbe application of these pritiojpltis will eoiin enable the proBpector to Tsork out the problems ior himself and test his theoretical knowl- edge by experieuce. "Pothules/' vbicb are Hmooth rouud pita worn in the solid rock by tbe eouataut fall of water charged Tvith sand, or the grinding action of an imprisoned bowlder, like a peatJe in a mortar, are apt to be swept clean of any viiluuble contents. Boulders m the bed of the stream of eouree act as riffles, but when large they add materially to tbe cost of mining, requiring derricks for their removal and mucb extra labor. If the gravel is cemented, as is not infrequently tho case, it may be uecesBary to leave it exposed to the air to slack, if the cementing material (as clay) is such aa will yield to such aimpe treat- ment; or it may be even necessary to pass it throui:h El stamp mill; but deposite of this character are not likely to attract the placer miner, as they invoWe the outlay of considerable capital, which ia only warranted by extensive explarations and the proof of eitonsive deposits.

Gold Pan. — Prospecting is usually dons with a larga shallow iron pan about 16 in, or more in diameter uorusB the top, by in. deep, with flariDg sides, stamped out of a single piece of chafuoal sheet iroD, called and well known aa a "gold pan." Such a pan filled with gravel and fairly heaped in the center will

Gold Qra Vml Deposits.

m

what he toy be a, , fouud out how luati or how many yai flluice box, both o

hold about 25 lb. aud about 150 pang are usually con- sidered equal to a cubic yard number varies with tlia aize of the ) ; Talues of gravel bein estimated either by the pan or by the cubin yard and not by the ton. A cent is a piece of old about in. square and half as thick as a ¥5 piece, as an approsimatjou to giva some com putative idea of size and value. With these figures the pi'O&pector oatt form aom idea of to do daily, as soon as he has pauB of dirt he can weak daily of gravel he oan shovel into a which will vary according to the looaUty the character of the ground aud the dis- tance to water. Peraiatsot panning is the only tiling which will test a guluL, Just as uue swallow does not make a aummer, one pan of ood dirt does not make a mine; uor doea the failure to &nd gold in the Brat pan prove tbe loaality to be barren. Aa a usual thing an Abundance of quartz pebbles in the gravel is a good iQdloation, and when these are aocouapanied with an ubundaDce of black sand, minute garnets (transparent and red) and small rounded shot-like pebbles of obrome iron, it ia not well to be easily diacoaraged. The signa of Gourse may fail, but they are what tba Mexicans terra pintas or colors, and call for a thorouiirh search. If the deposits are too poor to be worked by these primitive methods, but are shown to carry gold (aa proved by extensive panning) over a large aud well defined flrea> we tnny resort to the methods employed in Hydraulic mining, by which we can move and wash per man so vastly uu increased quantity of gravel, that ground very poor in its average cotiteufca may prove remunerative but we must remember that the hydraulio iQiner always calculates on a rich bottom streak which haa to bear the loss, if any involved in removing the top dirt, which may sometimes be a valusleas clay; and generally stops work on the hank when the limits of thiB bottom atreak are reached laterally

290 Prospecting And Valuing Mines.

By hydraulic raining we anderatanfl the ubg of water under pressure; that is to say, at some suitable poiat the stream is turned iuto pipes whicli couvay It to tba J ground to be worked ; aad by this raenDa we take ndvau- ' tage of the weight of the water in the pipea to force Jarge quantitiea through a nozzle, aud secure a power to out away the gravel bank without the aid of pick or shoTelj and wash the material into suitable Bluices, According to the preggnre or bead and the aniouDt of water xiaad a miner*a inch of water'" will wash from 3 to 10 on, yd. of traveL The "head" is the differ- I ence in height between the paint at which the water ©nterd the pipe and that from which it is discharged; while the "preaaure" laequal to the weight of a column of water of this heightraultipliedby the crass aeetioual area of the pipe, both in feet, by the wei of 1 cu. ft, of water, from which must be deducted the loaa caused by frictioa (ealled the friction head) agaiuat the sides of the pipe, which will be governed by its leugth, size and eouditiou of its interior as regards smooth nese and oleanliiteBs. This loss m greatest in small pipes, I

It is evident that the grade of the gravel to be worked will depend on the number of yarda which can be moved daily by a given quautity of water, aud that this will depend on the pressure ujuler whiob the water is used. To iucreaaa this pressure we have to gain altitude, and this farces the head of tbe water Guppl}' further and further back into the mouutaius; and as this supp]y must be constant diiHtii; time of rain and drought alike, we are compelled to build reeervoira, into which tbe various luinor HOurcoB of supply are collected and held in reserve. When ive remember that iifiines such aa those at North Bloom field and Cherokee Flat, using 2,000 miner's inches or over, consume daily more than 33000,000 gal., or water sudicieiit for a citg

S,SBO OIL ft.— a tank lS£lSil5 ft. (See Ctiapter ZVn. on Water.)

Gold Qba Vel Deposits,

of 350,000 inliabitants, it is not to be TnfonderecJ at that there must aometimes be an expenditure of $400,000 or $500,000 on the water plant before a yard of graGl can be washed. With such a heaty preliminary ex- penditure on water, besides the cost of tnnnelB, Bluiccj buildiuK, etc., at the miiie, annual repairs and working expensea, we must have correBpondingly large deposits of gravel to justify the enterprise. The North Bloomtield Company in 1879 used 931,000 miner's inches of water (15,000000,000 gal.), each inch of which moved on an average about 4 cUh yds. of gravel, or a total of about 3,724,000 cu- yds., eq.ual to 2,310 aores 1 ft. thick, 231 acres 10 ft. thick or 23 acree 100 ft. thick. The actual area removed, was prob- ably about 7 acres some 300 ft. in depth. These are of ctiurse outside figures, but they eniphsize very strongly the neceeaity of a thorough inspection of the water supply, and the facilities for disposing of or im- pounding the dt'bria, before opening an extensive hydraulic propoeitiou. It is tJtae enough to test the luulity of the bank when the water and debris ques- tiouB ere settled.

It would be beyond the proper scope and purpose of the present work to enter into the details of tbia highly developed method of mining. For such infor- mation the reader is referred to *'A Practical Treatise on Hydraulic Mining in California/' by Anguatna J. Bowie Jr. ; "Practical Notes oti Hydraulic Minintr," by Geo. H. Evans; ''Manual of Hydraulic Mining for the Use of the Practical Miner, " by Tbeo. F, Van Wflgenen, and other hooka and current literature.

Drift Minuii/.—TheTQ are, however, large bodies of gravel which cannot be handled by purely hydraulic methods for one or other of the following reasons : (1) The water supply may be totally inadequate, or the deposit m&y not ju&tify the expense of briDging it on the ground; (2) the dumpitig ground iilso may be in- adequate, or local interests may prevent it from balng

293 FROSFSVTWG AND VALumo MINES.

made available; (3) the top dirt may be eo thick and worthless as aot to trarrant its removal; (4) tbe de- posit may be entirely capped witli lava, whicla cannot be ecouomically remoifed; (5) the ravines on either eide of tbo ridge containing the channel may not have been cut dotvu deep enough to enable ub to put in a tunnel on a bydrauUc grade, or they may be too flat for suitable waabing sluices; or (6) tbe ravinee may be eo hih tliat tbir bottoin is above that of tbe old uhau- nel, BB iu u! 10, fig. 3, and oannot gain aocesB by tunnel under any conditiouB.

Iu this lagt ease it will be necessary to Tork the niinci with pumping maoLinery through either shaft or in- cline, of which latter method the auccessful Damascua mine in California is a good example; but in this iu- stancB tbe incline followed the channel on its deaceud- ing grade, and did not involve the dead work of shaft- ing, tbe use of which cannot be eaid to have been more tbaa partially succesEful. In all the other casea bed- rock tunnels are resorted to, which are run through the riru on a water grade until the channel is reached, wheu the gravel is exti'acted and haudled in cars very much in tbe same way as a coal mine is operated. Water can be accumulated intil sufUcient gravel ia taken from the mine, and a clean up oan be made daily, weekly or monthly as the ease may be. Having to wash Bo small a quantity of gravel, comparatively I speaking, tbe sluice boxes may be small, and but little water ia required under very slight prKSsur© or none at allj so that tbe plant is not neceseariiy ooetly. Given the gravel tbe success of drift mining depends on the location of the tunnel with regard to the bottom of tbe channel, for many laouthg of labor and many thousanda of dollars may be expended on a tunnel which may bo valueless if it should unluckily enter the gravel above tbe bottom of the cbanne>J, which it is unable to drain and render workable, as is the case with the lower tunnel in pi- 11, fig. 2. It is infinitely better to be

&Old Gra Tel Deposits.

too low tLaD too bigh, but the locafciou of these tunnels IB a problem whiob will sevGrely task the enginciBr and geologist Qombtned.

The greater nuiDber of the drift mliios are located well up in the Tuountaiss, on the Bteper grades near the hegd of the old channels, and it ia only here and there that the shape of the country baa caueed the re- moval of tha lava cap and espased the underlying gravel in such a shape that hydrauli work was pos- eible, so that long stretches of the ancient river Sie be- tween these isolated spota where the altitude of the bedrock has bseu BBcertained. In these unexplored sections it is only by inference that we kiiow the chan- nel to exiet aud numberless abandoned tunnels abow how little the miners were acquainted with ite struo- ture. To opeu a mine in such a situation is a delicate task and can only be aafely done after boring acrosa the general line of the old river, to risoertain the true position of ita deepest portions and its depth from the present surface. But before this cau be done we must determine the course of the old stream so tfaat we may be sure that the bore holes are- located acrosB, and do not follow it lengthwise. To make certain of this the rim of the channel on each side of the ridge must bs carefully traced out and platted as pi- 11, fig- 1, noting where the lava pipeclay or gravel shows in contact with it; and the survey should be extended to include the bed of the ravines on each aide of the ridge; levels should be run the entire length of the rim and the creek bottoms with full uotes of the racks exposed in the latter, and these levels will disclose the exposed OEida of the lateral atreama T/F which will outicrop in the lowest parts of the rim. When such a survey is platted we can approximately draw in the center line of the main channel, and of its branches on the plan; which will cover only tlie raain stream where its rims are approximately parallel, or tho main stream and a lateral if there are wide expansions as at OP, aud an

?nosPECTma and yalviht Miss.

eiposura ns at /. Prom these tlato we ftan an approximate croae section At any point, auoh db pi. 10 dgt ill nhich tbe rims are at the same altitude, makiug tlue uueeeti slopes of tlie old river of and gf, the aftiue aa thoae visible between the rim a aud the bed of the oreek h. It is evident that under such condi- tioQS the length of a horizDntal tunnel to taji tbe bottom /would be euuftl to tbe width of the obannel between the rims a ff, us the triangles dca, 06/" and fbg are all similtir. !Mi>i'e difficulty will attenJ the detsnuination of the length uu snob a line as OP, pi. 11, fie. 1, but the aolutiou prfictioable as an approximation. Of courie tbis -ha not an absolute method, as it is baaed on the probability of tbe same rock taking the same or practically the same slopes when worn away under similar conJitiona, and this may not always be tlifl case; but it will do to determine whether a tunnel is feasible, as, if the diatanoe to the creeks as from e to is less than one-balf tbe width between tbe rims, tbe probabilities are altogether in favor of tbe condi- tions shown in pi. 10, fig. 3. If the riaia are of differ- ent altitudes, as in £g. 3, tbe center of the old chaDnel will probably be located proportionately nearer the lower rim.

If this preliminary test prove satisfactory we can locate the borings with certainty, and they should be not less tbau three in number, probably five or up- wards, aa their respeiitive depths may indicate. To ascertain the probable grades of the channel we must eiteud Our investig;stiona to the beds of the crete 011 eaeh side of the ride, as it is important to know be- forehand whether tbe country is faulted, whether the channel is choked by bowlders, and whether we are likely to euGonnter flat, moderate or steep grades in tbe ground wbeu opened, as bad faulting might lead to failure and might not be diiclosed by the borings; bowlders are more difficult to handle even than in tbe open air ; and the grades, as we Lave seen largely iu-

Gold Gsa Yel Deposits.

fluenee tLe amount of gold in the bGclrocU K**QTel. There will probably be under aoy circutnatauoes a slight flalteuing at the junction of each lateral branch with the main streain. By examiDing the modern rayibes we may possibly find in each & band of rock bb F, pi. Hi £g. 1, which is easily recoiDizable, and by using this as a common haae, and following eacii ravine both up down with a tine of lerela we can arrive at a very fair idea of the probabilitiea where we cannot see the bed of the channel frotn what is visible in those of modern origiu, especially if we find the rock strata occurring in orderly aucceBsion in each stream, on all points on which we deeire information, whether it be faulting, dip of the rocks, accumulation of bowlders or grade. It would he poa&ible to enlarge on this theme almost indefinitely butenojgh has been snid to fiirniHli the ke3* to the methods of exploration, which must be vBTJod to suit each rJirticular locality; and the miner, by the aid of this key, can study for himself the chances of Buccees. The boring is not iliEBcult or ex- pensive, and nill be nearly as satisfactory an open shaft, which will cost more, take more time to sink, and might not after all be EnitHbly located. Th6 trachytic lavas seem abound in ehoke-rlanip or eai"- bonio acid gas making good ventilation in the bbafts imperative.

Marhitte Washivfj. — The operations just spoken of are bathed on the use of large quantitiea of water in open sluice boxes, in which there muat inevitably be a lofls of tine gold, an the records of the undercurrents show. Workings on a large scale have demonstrated the prenenoG in gravel of gold bo fine that it is not visible in the pan to the naked eye, juet as reoaoning demonstrated should be the case in gravels which owe their origin to glacial action, or which contain the products of the decomposition of pyrites. This very liue gold must certainly be swept away in the swirl uf Buch streams as are uged in either hydraulic or drift

k

Dperatiotis, as it takes a loDg time to aettJe even in atil] water. To aave Buch gold it luuBt be brought into coDtact with quicksilver in such a way that it oannot escape gmalgaination. Such is the intention of all mecbanioal appliauoes which have been proposed. It in sufficient to say that hy their means gold baa been Baved whioh ie eo iunitely £ne thiit it can be applied as a paint od paper, producing a gilding amoothor and tbiuner thau gold leaf. Its presence liaviug beeD demonstrated, the apparent absence of gold tn the de- bris from localities where auriferous pyrites have been largely denuded iseipiaiued, and the metal is probably much more widely dis&emiDated than has heretofore ben Bupposed. The discovery of gold iD this condi- tiou and the ability to save it may have far-reaohing results in gold mining, especially as in talcose rocks and serpentines cauch line gold occurs as jSlms of iu- iinitesimal thinDess, hich increase the value of the assays, but is ea.tieediDgIy difficult to save in the mill. Ih a piece of solid rock we hve the material con- trolled, no matter bow fine it may be, and can detect its presence by aesay of even small samples, but unfor- tunately vre have no way of conoentrating gravel so as to get suitable assay samples except by laborious proceBses and may have to depend on workiog tstB for the detection of such gold.

Test/or Fine Gold in GraaeL — Probably tbe best ei- perimental method would be to wash a large <iinmtity of gravel, previously measured, in the same water, never allowing any of the latter to escape, but uamg it over and over again, retaining only the iineat sands by a proper system of screens; and when a etiitable quantity of sands had been accumulated they naitht be treated by the chlorination process, which dissolves every trace of fine gold iu the mass and saves nearly all of it. The result obtained divided by the number of yards of gravel concentrated would give the average value per yard, EUid thia might be greatly

Goli} Oea Tel D/Sposits.

more Umn alioTvn by teat wortiogs in tlie sluice bos The differeoce between the two results would be the iuvisiblo gold.

All mnchinea suitable for this claims of work use much leas water per yard of gravel washed than is neoesBfirj in hydraulic operatioua, and this in a most important item if the dejiosits are no situated that pumping muHt be reported to, as a good head of water (pumped) wili coat from 15 to 30 cents per miner's iacb according to 4he height to which it must be raised, and the length of the pipe tbrougb which it has to be forced, or the coat of labor and fuel.

Washwg.—The difficulties attending the sepa- ration of gold without the use of water, or as it ia oalled rather c!urioH9ly> "dry waHhint;, " are enormous, and it can only be attempted on the richest bind of material with even a shadow of euocesa. The great mistake is made, as in so many atlieFmimtng machines and proaesaes, originated by perarms who as a usual thing ate'totally ignoraat of what baa been attempted by others before they bsoame inoculated with the idea, of supposing that tho careful manipulation to which the inventor subjeota the small quantity of material on which he operates can be repeated on a large scale in actual raining. For auoaess it is absolutely necessary that the material should be absolutely dry and tbor- oughly jjiiiverized, as any moisture, especially in clayey soils, will prevent the grains of gold from separating from the earthy matter.

Hydratdic Seuo/ors.— Not a few localities in which gold is found abundantly pTBScnt dicultiea due to iusuflfiaient room below the deposit, on which we can construct sluices of sufficient leagfcU to properly wuah the gravel, and in which we can deposit the debris after it is washed. lu such oases we are com- pelled to resort to hydruulic elevntora, by which the gravel is lifted from 30 to 50 ft. or over and there dumped into the sluice boxeSj, which can then be from

FROSPECTINa AJfTD VALUmO MINE3.

one-eighth to a quarter of a mile longer than would otherwise be po'sible. The method ia of aourae only AV&ilable on moilevately coarse material, a9 tbo diame- ter of the tube and the force of the lifting iefe prsTent the pH&saffQ of very coarse material.

Eimr Bar.i. — TheBs usually form at the junction of two etreauiij, or just below the point at Tvhich the cur- rent is deflected from one aide of the river to another, If a Btream ia auriferous, theas bars are often riuh in gold* which ie brought down, in flood frinae from the upper country, often many miles. The Snake Colum- bia and Fraaer Hirers ara good examples of such atreamB, in addition to the well kuown California localities. On the Fraser, at Yale, the amount of fine gold brought down by the stream, to localities not less than 50 miles from the source of supply, is so great that the surface of the pebbly barg, which act aa rifllea, pa>'B to work over annuullyj and a panful of moss gathered from the bowldera esposad betwoen high and low water mark, will show from Hffcy to seToral hun- dred colors. It can easily be understood from this that bars which have remained untouched for years may therefore be very rich; immGnaely so in some in- atatioee. Hill's bar, below "Valev must hate yielded many dollars per cubic yard, when seven men with three rockers took out $90000 in 90 daya> These bara may be so near the level of the water, that it inter- feres materially with working them. In such caaea WinQ dain, are resorted to. Theae structures consist of a wall of brush and bowlders, built out iu the shallDW water at some suitable point abore the ground to be worked, to divert the current and iuelose a Iplock of desirable ground. The current is used to run water wheels which pump the incloaare dry or sufficiently bo to enable the working of the gravel to be succeaafully carried on. Such struotures are of Course only aTnilable during a low stage of water, and any sudden flood is apt to wash them away, making

the operation risky, as a wLole aeaaon's work, qs Well as the money invested, may be lost in an hour. In some few cases it maybe possible to divert theatreanij wliioh 19 a more satisfactory method if the ground rendered sTsilable is sufficiently extensive to justify the expense. Probably orte of tbe mast GuccesBful entorEjrisea of tbia kind wab ou the Cape claim near Oroville, in California, the owners of which in early days turned the Feather Rivsr into a flume 40 ft. wide, and deaDod up from $G00,000 to $700,000 in one fluraiuer'ft work, Although they lost the Hume during a sudden freshet before the job was completely finiabed.

Dredging the bed of tbe stream is sometimes resorted to, it being reasonable to suppose, from all we know of gravel mining, that if the bars in a river are worth working, tbe gravel beneath the smfrtce, wbich we cannot see, must also contain gold in paying quan- tities. Such dredges are in succeBsful operation in several localities, both in America and elsewhere. Some machines can Landle ob much as 150 tons of gravel an hour; but tbe quantity, aa well as the suc- eesfi of the dredge, will depend largely on the character of the river bottom. If it is encunabered with large bowldera, it may be impossible to work it to advan- tage, and the be.t results will be obtained in moder- ately fine material of a uniform character.

Adjuslmeiff tjf Savutg Ap])l/'a}ices to the Size of the Gold.— 'la any appliance for workiug gravel by water, the meaBure of Bucceas will largel.v tlejiend on the careful adjuatment of the amount of water need, and the grade of the tables or sluice boxes, on or in which tbe gravel Ja wuehed, to tbe size of the particles of gold in tbe material under treatment; and the finer and finer these become tbe more accurate must be the adjuBtment. There are many localities where the entire bulk of the gold is au fine that we have to resort to the use of the principleH involved in the undercurrent, or to the Use of amalgamated plates or to a lining iu the

Bcrma anp vALuma .

eluice bos, made of incli boards bored full of holfifi, to blaBketa. burlnpe, or rawhides with the hair point- ing up Btream, as in China; or to cocoanut m&ttins laid over a eoarse liueti cloth, as in New Zealaad. The localitiea where this ]ciii<l of gold ib chieJSy fomtd are along tbfi banks of large riTera and sea beaches, and the gold ia frequently accompanied by such large quautities of "black g&i:id" (consistiDg of magnetic and titanif trouR iron derived from the decay of erauitic rocka) that these, in any stream weak enDugb to saTa the ilaky gold, choke the eaving appliancea with a solid bed of iron aand, through wbioh it ie impossible for the gold to sink and reach the riffles or quick- eiWered Eurface below, and it ia con sequent] y passed on through the Bluic-eg, on the top of tbe sand. The only method of improving this state of affairs is to £rat extract tbe iron Band, or that portion of it which is magnetic, from tbe material under treatment so that the remainder may be tiutshed in a much gentler cur- rent than would be necessary to carry off tbe iron sandj and yet sufficient for the task of separatism; the quartz Bauds from the gold. Yarious appliances have been designed to work these sands, but until recently they hae met with but a very limited abare of auo- oess. There appearSj however,, now to be a prospect, by the use of magneto-electrical appliancea, of making more progress in the solution of the problem, which ie a fascinating one on account of the abundance and widespread area of the material and its constant restoration by the operations of Eftture.

In working this class of material, the aim should be to make tbe machinery as light and portable as pOBsi- ble, BO that it may be readily moved to the material instead of hauling the material to the machine, as this rapidly becomes an expensive process, for while the materia) may be abundant it is usually of no great thickness at any oue poinL This is particularly the case in beach sandst which may be scattered by he&T/

Gold Qra Yel Deposits.

storms audi afterward reaaaorted hy f.lie gentler action of the waves in more moderate weather, which pan. out the lighter particles of sand, leaving the gold and iron in a concentrated form.

Throughout this chapter espeoial attention has been paid to gold, but the eame priuciples of prospecting and working are equally applicable to all minerals found in similar couditionB, such as tin, platinum and itai allies, and even native silver aa at Planchas de Plata, in southern Arizona. Thsse metals are, how- ever, all worked in open air placera, and have not yet been found, bo far as the writer is aware, in paying; quantitieB in drift operations, though platinum and iridosraine are found in nearly all the gravel diggings of Cfiiiforniaj along with occasional diamonda.

tlHAPTER XVn.

Water And Its Measurement*

Walter plays so important a part in all miDing operations that the &7ailable supply becomes a vitui queation, whether for jold washing, for power or for millint; aad Uoiuesfcio use, Tbefollowiug sitnple rules for ascertaiuin the quantity Jiud eatimatiDg the power 'whioh can be derived from it will! be fouDd useful in this conuectiuD.

Unit. — AViiter may be lueaaured by the galloDj the cubic fool i>r the miilur'a iDch, aud the uae of the special tei'iu depends Huruewbiit uu the purpose to which the water is to be applied; thus, city supplies are usuaJly estiiuatad in gallons; irriiLtiuu quantitied in oubie feet or miner's inches, and for tniuiuy; opeia- tioDB on a lare aoale almosft uutvarsally iii inches.

Weiifht. — A cubic foot of freah water, with the barometer at 30 in., weighs, at 30 F-, 62.423 lb.; 62.367 lb. at Hi)"; 62.218 lb. at and only 59.7 lb. at 212°, a fair average btiing G2,33 lb,, but UHually callecj 62.51b. for convenience. JJelow 39' the weight deoreaseB, bo that at 33", or the freezing poiutj it ia only 57.2 lb. anJita apeeifiu jjrravity only 0.9195. Seft water wei;bs from ()A.02 to 64,27 lb. per cu. ft.

Bulk.— A. gallon of water XT. S. etandai'd containa 231 cu. Id. This is equal to a cylinder 7 in. high by 6 id. in diameter, or to a cube 6.1358 in. on the edge. and ie 0.13368 of 1 cu. ft., so that 1 cu. ft. containa 7 AS gal., or in general terms al.

Miner's Inch. — Thia is the quantity of water which

WATMJi AND ITS MEASUREMENT. 303

will flow tbtongh an orifice in a 1-in. bowd, 1 in. eq,, in 24 hours In selling water, however the water Gompauies Bometioiee ]mak6 rates hy tbe 10-hour and 12 Lour in,, users not requiring it for the full 24 hours. The inch varies according to tbe pressure under which it is disGharged. The term arose in Californioi in the early days of gold xuining, but th customs of diSer- ent campa varied, as the "head," by which is mflant the diefcauce from the top of the water to the center of the hole, ranged from 4 to T, or sonietiines as much a8 8 in. The 4-iu. head is still used in the irritjation districts of southern California, but the 64n, head haa of lute years been considered the standard in mining eatiruates. Uncler a 4-in. head, through an oritice 1 in, sq., the disoUarjie is equal to 1,728 cu. ft. or 12, 95 gal. in 24 hours. The 6-in. head discharges about 2,150 co. ft,, or 16,083 gal. in the same time. The North Bloomfield reports, ae the reeults of esperi- meats hy Hamilton Smith, give 2,230 cu. ft. or 16.680 gal. The measurement is made hy leading the water into a tank, provided at a height of 2 in. from the bot- tom with a horizontal slot of given dimenEtions, say 2 in., which can be olosed by a moving bar, eliding in it. If it is desired to ujeasnre all the water, this bar ia slid back uutil it allows the water to escape at such a rate that the surface Btnuds coDstantly at the re- Quired head, and the @ize of the aperture can be read o3 imoiediateb' by t'raduatioue on the bar. If tho Blot is 2 in. high and the bar has been slid back GO in. the flow will equal 2 X 120 in. If it is desired to measure ofl a definite quantity the slot or gate is properly adjusted, and the waste gate opened until the requisite head is obtained in the measuring tank.

PrtiMiire. — Water oserta the same pressure in all direetions. In pipsB the pressure is equal to the area of the pipe in feet, multiplied by the vertical height of the pijie (not by its lexigth), and ths quantity thus astiertqiud by t)2| lb* (the weight of 1 cu. ft. of

pRospEcrmG AND YALum& Mmsa.

water), or if the area is oalculatfid in inohea, by 0.132292 of a pound (the weight of a columji of water 1 in. aq. and 1 ft. high), and this by the height ver- tically of the pipe in feet, the i'eault will be the pres- sure per inch in pounds. Moving crater exerts lesB praesuve than when it is stationary, but when out off suddenly puts a greater strain on the pipe than the aimple stationary load, to which the monientuxui of the moving column has heen added.

The following table (condensed from Trautwine) gives the weight of water, at fi2j lb. per cu* ft., con- tained in 1 ft. of pipe of different diametera from 1 to 36 in. The fractions of inches are omitted, as seldom used in mining operations.

Weight Of Waiee In I Ft. Of Fife.

in

Weight, Lb.

Diam,

Iq

mam. in.

Wgghi,

Diam. in

Lncbes.

Iat;bBa.

TnchiM

Incbes,

0.389B2

1&

1&

S3

Ms. Is

S

n

41,082

£0

S9

%&.fi3

3.05.5T

Si

S*.S7

a.43S3

J9

57.37B

Si

1fl4.3a

Si

aag,s7

a.4esu

6fl.M5

S3

S3

13.S2S

76. Sos

Si

T

ai

Ss3.48 1

S

21,729

ffi.lSl

Sfl

za&.si

dlB.W i

fi

Ib

11(1.000

S47-5J

Sfl

The quantities increase as the squares of the diame- ter of the pipes, Thue a 36-in. pipe contains four times as much as one IS in. in diameter — MO to 110.

Discharge Ujider Bead.—Ihe discharge of a pip6 from the bottom of a reservoir is found by multiply- ing the area of the oriiSae by the velocity of the i&tiream, which depends upon the head or pressure. If the opening is circular multiply the square of the diameter in feet or inches by 0.7854, and this will be the area in feet or inches. The velocity of discharge ia ascGrtained by multiplyini* the square root of the bead in feet by 8.0Bj and the result will be the Teloc-

WATmii AND ITS MEASUREMEWT.

ity in feet per second. The foIlowiDg table (con- densed from Trautwine) gives tho Toloeity of dis- charge in feet per second for heads of from 50 to 500 ft. In termed i ate heads can be made proportional to tbe ueareBb iigures :

Velocity Of Dischaboe Tjndeejdiffekent Heaj>3.

HlMUl

veioeitr

Per Second.

Bead.

Vetodty Per BcGODd.

Eo

M.7

13S

fl9.7

fiO.B

9ft.3

W

17B

10&.0

6&

.T

i0

To

lacf.O

Tc

eo.s

aoo

Isb.O

eo

n.s

ffTS

isa.o

B&

13&.0

w

uo

l&O.O

Wh

78. a

Ibo.O

wo

Poioer nf Falling IVater, (on the assumption tbat one horfie power is equal to 33,000 lb. raised 1 ft. per minute), — Multiply together the number of cubic feet of water which fall per minute; the vertical height of the falL or head in feet; and the number 62,3 (the I weight of 1 en, ft, of water in ponuds) ; aud divide the result by 33,000. Thus 800 ou. ft. of water falling 16 ft. would give n thaoretipal horse power of 24.17. But water wheels do not realize all tins power. Undershot wheels only realize from one-quarter to one-third; breast wheels about one-half; overshotSj from two- thirds to three-quarters; turbinea and wheels of the Felton type from three-quarters to 85%. In general termB Jartie quantities nf water under small heads are best utilized by turbines; but above 20-ft. heada the impact wheel will be found satisfactory even up to pressures of 2,000 ft. The makers of the Pelton wheel issue a circular giving useful data in relation to the measurement and use of water, and from it the follow- ing tables are extraated. Th© first gives the h. p. of

30S

mosPECTmo and valving mines.

1 in. of water under beads from 1 up to 1,100 ft. ThiB iucli eqiiaU cu. ft. per minute- The table assumea 359 efUcieucy.

Taule For Oalgulatinq Horse Power.

Heads

HiTse

llendB

Horse

Heads

Horee

Headd

HOTse

in Ft,

Power.

In Ft.

Pdwer.

in Ft..

Power,

In Fni,

Power.

O.0O34Ut

o.wirM

Ito

n.41(Hm

4W

l.lStiMS

O.0Ml2;ffl4

saa

0.7WdBl

Iso

0.43Md

l.]iS3iKH

U

O.IJTMl

&40

leo

l.iWram

O.OafiWB

0.B45145

D.4Hsm(I

sa\

1.1H3644

n

o,ia>TK

aw

0,aS92BB

S10

O.&OTiiHT

1.803tt8

m

Bto

O.B934S

22U

U.Su]S1

i.assssa

To

0,1B90!?B

sai

o.eirsst;

sao

D.5S6S81

6S0

i.40oiwa

Bo

o.&4i:si

O.STPSEa

aoo

]. 448880

W

0.00511

O.iO&iTH

J.S69M5

O,M]4T0

y.9moa7

am

o.isiTsaa

Lososoo

0.8S5D1T

1,014174

sro

O.H51Bfi9

],S110Ss

Iw

CBRSTfl*

l.OdHSl

3W)

0,076110

Soo

1.93i?1

Isd

3]:i9t]

1 DfiSlfiJi

0_Toos(B

Iju

O.WffirBH

4S0

1 .05bl5

30(J

0, 74110

S.41471

Igq

ij.aeaaoB

4B0

1.1107ft2

S.asfllTO

leo

a.3tS368

45T)

MeaMiiTe.mpni btj Weirs. — lu general terms a weir IB auy Qbatruation across strenra as a dam, over which all the water in the stream ia compelled to flow, or BO muoh of it as may be desired, which can be regulated by suitable waste gates, which will maiBtain a constant depth on the weir. Select a place in th stream, where on being dammed a pond will be formed of sucient length to check the Telocit3'' of the stream. Acroaa the lower end of this spot place a board or plank, in which a square notch hag been previonaly out through which the water must flow. The length of the Dotcb in the dam ehould be from two to four times its depth for small quantities of water, and longer for large quantities. The edges of the notch should be beveled toward the intake or upper side, and the clear fall below the notch should be not less than twice the depth, that is 12 in. if the notch is H in. deep, and so on, to prevent loss by backwater. In the pond, from 3 to 6 ft. above the dam, acoording: aa

iTSR AND ITS MEASUREMENT.

atream is Binall or larg©, drive a stake, and then obstruct the water until it rises preciuely to the bot- tom of the notch (which must be level) and mark the atuke at tbia level. Then complete the dam so a& to cause ail the iater ta flow through the nutch, and after allowing time for the water to settle, mark the stake again for this new level. If preferred the stake oan be driven with ita top precisely level with the bottom of the notch and the depth of wnter be measured with a rule after the water is flowing freely through the notch, but the marks are preferable in most cases. The ditttDce between the niarkB is the theoretical depth of flow Corresponding to the depth in the tnble, where an example ie given of the method of making the oaloulation. The quantity obtained ean be couvei'ted into gallons or miner's inches as desired.

The following table will save trouble in making oom- putatzons from weir njeauremorite :

TABLE FOE. WEl MEASUREMENT,

GiTiaf cubic feet of water per mlmite that will flow over a weir 1 itl wldQ

and f fota % to 'ZfPj in, deOp.

InchiBS.

H

M

U

%

%

M

%

ni

,00

.3B

.s

.Sb

.M

,73

sa

.(fi

i.os

i.as

1,35

l.TO

l.ta

i.gs

B

s.or

S.2I

£.34

S.4S

fJ.Sl

3,73

2.0(1

3,0A

fi.SO

8.3tj

s,m

B.sa

s.m

4. so

4,&1

4,8t

5.B3

fi.liO

B.8T

6,25

e.ffij

7.m

7. Si

7.Isu

S.42

S.6!l

S.B3

A

9,i5e

&,47

Do?

9,01

Id. 13

Id.Ho

11, ar.

n.4fl

J1.7]

t2.fl4

is.ys

Is, 13

14. B4

15,00

1ft, r>o

ifi.as

17,16

17. B7

17. W

lrt.31

lfl.47

18. T4

10, So

10. M

lfl.S4

ai.n

20.. Ib

BO.ff?

3D.Sa

fli.f:]

93, Ki

s*,8r

ss.es

ffl.04

S4.n

Eg. 30

ai.M

K.sn

fl().M)

Sfl.SO

ffi-.It

l&r.4S

as. OS

2H.a4

28.gr

So.Ss

39,81

so.ss

So. 54

80,8f5

Hi, 18

31 -W

aa.is

S3.4T

Ss.45

S8.7H

At. 11

Uaa

as. 10

S5.44

So

Bs.Tt

80.45;

Si.Ti?

ar.eo

S8.16

Prospecting And Valuing Mines,

Suppose the weir to be G6 in. long, and the depth of wnter ou it to be ll| in. FoUcw down the left band columu of the Bgures in thtRhle Udtil jou come to 11 in. Tlien run norosB the tnble on a line with the 11, until under on top line and you will find 15.85. Thia multiplied by 6G, the length of weir, gives 1046.10 the number of cubic feet of water passing per minute.

Measii.rcm.eiit in an Open Stream by Vdociiy and Gross 6*edion.— Mensure the depth of the water at from 6 to 12 points acroBS the stream at canal die- taucBB between. Add all the depths in feet together and divide by the number of measurements made; this will be the ftveraee depth of the stream, which multiplied by its width will give its area or crosa section. Multiply this by the Telocity of the streatu in feet per mlQute, and you will b&ve the cubic feet per minute of the etream.

The velocity of the streain can be found by laying off 100 ft. on the bank and throwing a float into it at the middle, notinjj; tlie time pnaaitig over the 100 ft. Do this a number of times and take the average. Then diyidiug this distance by the time gives the velocity in feet per minute nt the surface. As the top of the stream flaws faster than the bottom or sides — the difference beinj;: about S'(J'— itis better to measure a dietance of 120 ft. for doat aud reckon it as 100.

This method oau also he applied to measurements of water in flumes. The error will tend toward excess, if the friction along the sides and bottom is not allowed for.

Water And Its Measurement. 309

TABLE FOR MEASURINO WATER BY MrNEE'S INCH.

Leoetb of Opening iQcliea.

OfADinea 9 Inchea HiRb.

Head to

Ceuter

6 Id.

Oil Ft.

Head to

Ceoter

a in.

O-a. Ft 1.47S 1.4U I.4H5 I.48T

I.Am

1. 40] 3.4Hs

1.4S9

OpeaiuRS 4 Indti Hib.

LflOB

,610

Head to

Center

5 in.

Head to

Center

6 in.

Cu. Fr, 1.32t) l.SM 1.3&4

1.3&7

1.3G1

1.B65 l.ME

Cu. Ft. I.4fiO

l.fiOO 1.M2 l.fi(H l.,505 l.MH 1.50S 1.S09

Head to

Center

Tin.

Cu. Ft. 1.B70

Ld9a

l.filft

i.esa

i.tss

I.Sw

t.est

, 1-632 1,634 1-63S 1.B99 1.64U 1.0*1 I.B41 1.04J 1.M2

CHAPTER XYHL ARTEfilAK WELLS.

Definition. — Strictly speakiug, an artesian well ehould flow naturally over the top of the pipe without pumping. Tbe name is very Irequeutly but erro- D Bously applied to any bored well but aucL wells merely diJller from any ordiuary well in the size of the hole aturl the luethoil of lining it.

Thuory. — Artesian wells depend for their succeBs on the property of water fiading its own level, or the tendency to stand at the same height in both the legs of a tube bent into the abape of a U. We muat there- fore have for tbe source of water a region bigher than the one where the well is to be sunk, and even then owing to the friction in the ground and tube, the water will not rise quite to this level-

Basin Wdia, — Ta secure the best results we niust have a saucer-shaped basin of strata all dipping toward the center, and no part of the rim of the baain must be lower than the point at which the well is sunk (except as hereafter explained); and this basin must be filled with alternating layers or strata of material which wiU allow the ready flow of water, such aa gravel; and others, such as clay, which will not per- mit its paBsage. Such a condition of the atrata is shown in pi. 14, fig. 8. To make it more intelligible the vertioal heights are made out of proportion to the horizontal but this does not a£fecfc the prmoiple.

We have here three beds of clay, and two

Artesian Wells.

beds of gravel g and with Burface dirt a. Now if a ell be aunk at the cButr uf the bBin, as at ut, it TTould penetrate all tteBe beds. The upper bed of clay c would hold water, and if the well did not go through it we ebould have only an ordinary well. But as the stratum of clay c would prevent aay water which fell on the surface expo8,urs of the gravel g from reaching the surface again, this bed would form & reservoir m whJoh the pennatient water level would be the height of its lower outlet. If then we extend the well into the gravel g we should make a lower opening and the pressure in theundergrouudreserToir would force the water up the well, and perhaps over the top. But if we extend the well through g and th olay b into the gravel e we shall have tapped a larger reservoir, the gravel being thicker, with a larger sur- face exposure at a greater height, and the increased pressure will cause the water to rise above the top of the well, giving a permanent flow without pumping. This is a true artesian well.

It might however happen, as in pi. 14, fig. 9, that a portion of the strata had been out away and fiubae- quently overlaid by horizontal depoaite as at c, but if these should be a retentive olay, the result would be the same, as the lower edges of the gravel g lying be- tween the beds of clay a,b, would be hermetically sealed by the clay and the well w would still be artesian on account of the pressure resulting from the altitude of a and h.

From the foregoing it will be seen that the beet results will be obtained in those wells which are near- est the oenter of the baein. These will be under greater pressure than those nearer the rim of the basin, and the How wilil gradually diminish aa it ia ap- proached, until thogo nearest to it, penetrating the retaining clay higher than the natural outlet, will have no overflow and become pumping wells. The central wella will, however, be more expensive to put down.

312 pnosPEcrma and valutng ,

Exceptional Gase, — Otber oflusee, however than tb& ocaurrenoe of sQucer-sltaped basiuB may give riae to favorable conditioiiB for arteBJati velle, &s in the ccise of San Bernardino in Southern California, wliich lies a few miles north of Colton. All tbe wells in the latter town are supplied with windTuills, while in S&n Beruardino there are upward of 800 artesian wells. fumighin an immenee flow of water. The quantity is so great that large irrigating ditcLea are supplied from this aource. The boundary line between the two regions ia a nearly straight line running west of north. Along this line there baa been an immejise fault acrosa the wide valley of the San Gabriel Eiver, with its alter- nating beds of cla,y and gravel, which has raised the solid rock on tbe west, until it acts as a retaiaing dam, converting tbe valley to the eastward into a huge utderround reservoir, very much as in ph II, Og. 4, where AS may represent the fault, forming the reaer- voir P, so that while wells to tbe left of A would re- quire windmills those at 6' might be artesian, (The illuBtration ia drawn for a different purpose but the relative position of the rcoka and gravel bedB ia the same.) Here the water finda its way into the np- turned edges of the strata, bounded by the two walls of the valley, and not being able to pass the barrier of rock at the western end of the valley ia forced to the surface through any opening piercing the retaining claya. That this is the case is proved by the wella being deep close up to the break or fault instead of encountering the retentive claya fit gradually dimiu- iahiug depths going westward.

Bequisite Conditions. — In the caee just cited, the fault having become impermeable, or not affording an out- let for the water, an artesian basin was formed where none would otherwise have been poBsible but it doea not always follow that because we have the proper shaped basin it will furnish an artesian flow. If the beda of clay are thin, very alight earthquake dia-

Ahtestan &Lls.

iurbaDces mA liave broken tbeiUi so tbat they no longer act as retaiuiDg wallB, but aJlow the eacape of the water to other lower strata where it may be loat; or the gravel beds may not be c out in none over large areas, but eontained instead between two layers of clay united all ronnd like tlie cruet of a pie over the fruit, in which case there wonld be no presence; and some- times, when the How is smalb a deeper siulting in search of a greater supply maj' allow the water to escape into a lower stratum having a natural outlet, and the flow be lost altogether, So many contin- gencies surround the successful sinking of artesian wells that only actual trial can deterniine the proba- bility of succesa, except in casea where obviously there can be no extensive basin aa in broken moun- tain countries.

The writer sunk 600 ft. in the San Joaquin Valley, Cal., but never found water which came nearer the top of the well than 12 ft., while fui'tber norths in what would have been deemed a less favorable locality, 18 out of ID wells were successful and the deepest was less than 200 ft.

While gravel has been spoken of as the source of water lu the foregoing pageSj it may be found in any other porous rock which will easily pernjit its flow, sucb aa sand, sandstone, conglomerate, shal, chalk or even litnestone the essential point being that what- ever its nature it must lie between two n on -permeable strata of clay or rock. The retaining ati'ata, instead of clay, as assumed above, may be of any compact rocka such as hard and unbroken slates quartzite, etc. "Without these there can be no artesian welL When auoh a bed is found in sinking, the operator may expect satisfactory results not otherwise; and if water is found beneath it in reasonable quantity care should be taken not to break the underlying one, for the reasons already given.

If successful, artesiaa wells we invaluable for the

Probpectinq And Val Uinq Mines.

water aupp],v of cities jtud irrigation, as, though m some caaey their lirat cost may be Ifirge, it is not inva- riably BOt bub on tile contrary often quite moderate, and the annual repairs are nonjiuaL

Permanence of Supply. — The well at Aire in Artois, France, has giveu a stream rising II ft. above the sur- face for the last 100 ir%arB, but in some cases wbex'e the success of tbe experimont has induced the sinhiog of a large uumber of welle in the same "basin the con- sequent iucreaBe in the aize of the outlet, combiocd with escesaive demauda on the reservoir, has dimin- ished the pressure aud reduced the flow, aa in the London basin in England. Aside from such caunes there is little to fear escept from destructiTe earth- quakes which may rupture the strata, but fortunately these are rare.

Examples.— following table of a few wells will give Botne idea of the depths which have been attained and show that there is no relationahip between the depth of the well and the quantity of water obtained. In "'Physical Data and Statistics of Calfornia," by W. H. Hall, there are minute details of many hundreds of wella varying in depth from 90 to over 1,000 ft., and with bores ranging from 2 in. to T in. As is the case elaewhere, many of the wells proved Talueleas for either drinking purpoaea or for irrigation on account of the large amount of mineral matter (chiefly the salts of sea water) which the water contains, the amount running up to as much as 231 grains of solid matter per gallon; but the general results have been very satisfactory. The deepest bore reached a depth of 2,160 ft. without finding artesian water.

31& phospecting and valuing mines.

Thp atomic weifrh&s h'cn? KlTeo have been compiled by Prof, F. W, Ciiu-lre tzfwti a\.c. m<Mt teut and relielMc d€<CeriDiEiat.i<ina ostA ore adopted as stand- ariJ bj the Atnerk'nn Chemical Societjr.

In iLddltiDii to the fore-eoine thire are b nantlwr of supposed elements— uctiniuni, holmiiiia, iduniuin, lltiieai 111:1, muaudnum, utiptuuiuui, phUlipiuin annideL-fpiariL, not aiu'X'iit'd or vEilid Uy all i;}iemist?. Aii?in and beUum, hawtivrr, ere pliLCftd iii dii ]LHt, tliouh little kuown about tlieoi.

ITiD widt ratline in sptiQc ffrftyity duo t-.i iitjinirity of eauLjilps id som caeiefl; tempemliin; wtieu teiit; with luetalit whetWr cost, riUtid. hani- mernl. eU;. : sad to th(.< f iK;t tbat the deteripijjatitmg were tnmle hj dlSertUit c.fapminiLa. UHini; liilTireTit mtt!nj<la.

In the older yh'jTiiijTil nomcnclfttiire oxygen "M UffUtned lU 16 to 1 oT hydrouH. Ijiter deteriiiluntioDaLve 15. to 1. CoDBsqustitly the TsJuea nf atomic weJghte a.i- c>i-1CllJat<?il on Xwa sc&1t>M. on one Af bydlKTi la ULken m& 1, and ub the oth<u-, ozyiBit as 16. TbA differ&tu%H kta onJy frKUoDAL

QEHKBAL CLASSIFICATION OF MINERALJa CBRUBH).

L Udoraia MxTALLtc DR ScB-llIsn'jU.ua .

Mo.— SEInpralH haTinp mot/iUic Idstor are opaque, and do not traosmit: IMiteTPn thrnuph thir tiitrnest edges. The colorof tbe!r powder, or ifimk, therefi <[v iliirk, though DOt. rnKxssarjly bliuk. The inlneraJs with Bah-m*talllc luster wLieh ah? included in this Bectian &li ffie darfe-colored fttreaks. Many diirk-clonHl diimerais wboae Inater ia dotibtful bare been placed here,, aud also Id Section IL

A.— rCBlfiLB rfiOU 1 To 5r Da BASILI VDLiLTILK.

1, .j'wnie OsnyjUiind*.— B, E.on gha*coaIgtveftTolatilecoatIngof araeiiioua

oxkle.

2. S/tiitii> iirV)i7(.fjAti.>irij:.— B, B on chaivoal glva chargAteFiBtlf? ra--like

odor Impart iin Eusxire-lduc coJor to th ndiKin- . &. irilurii'm CXTrtfjfJitiMis.— vVhen treated in a tesMnltc trilh 5 cc, of coDcen* tmted H3SO4 aiid [?tuLLy lieatiMl, Ltie acid rrkuui a reddiHb- violet cotor.

4. lifimo'Fi/ Comi>fiiitn7s:.— U. B, on chmuvat givig adeyi? 'CFbite coating of

oxJde tif antimoDy. &. .— Wlien rOttStftd In tbe Opan tube or on cha-rcoal give the odor

of aiilphurouE anhydride, but do ntit givo the rsactiotla oC the preoedlo

divliilQtie. B. Not beloDgtDg to the foregoing dirisiona.

B.— INJTatBLB, OB PUaiBLI IBDTS K HDB-TOIOTILS.

1, JVon fJompounds.— Become mitgtieCfc after beating B. B. in tfas rediiclDK Bame.

5. 3f<inganrw: Compcntnds.— bnpart to tba borax bead [q O. F, a retdjafa

violet color. Z. Not bdonglag to the forgoing divlstana.

n. MiysRiLS WiTHOTrr Mxijjjjo Lobteb.

TJoTE.— Minerals -witliout metallic lueter are transparent, altbntigh they may hare such no Intense color that they trfljiamlt lielit only throturh vwy Ihln edges. The colur of their powder, or their atrealc is geaerallf white or Ughtolored, neTer black.

A.—HASiLX TOliATILB, Oa dOUBIiaTlBLB.

BapJdly disappear when heated B. B. on charet.

Useful Tables.

nraiBLE JTIOM 1 TO 5, A>fD Sfin-VOULTILK, OR OHLT SLoWLS OlL PAttTUl.Llf TO UTILE.

Pjt T.— GIto b Metallic Globwie when fused with Esodliioi c&rbODte on

cLaruo i]. 1. Silver Compounds.— B. B. with scxlixjni carhonata on chajroa] & it

lK-ti>buIu vC silver. S. Lead }oands.—B.B. with sodium (wrbnTiatnon charcoal give a globnle

of liarl.

3. Bixntnlk ChmpoimJs.— B. B. fiith sodium rjirbonato on ehar<al ffise a

lohuio of bismuth.

4. Aniimmip Comnintds.—B- E. wJth BwUiim carbonate on charcoal give a.

5 Copper ttoinjiDTiJirts.— B, TJ, with aodhim carbonate on charcoal give n glc>litilf lif qotmrr Till; powdi.Tfd (uiri'.-ml ou charcojil, aftir uiolHttniu with hyiirouhiHiirii: acid, Jmiiiarta au aziire-tilUB color ip f±ie bJowpJpe aanTH j.

PiRT n. IroTi ComponvAi- — Biume mlgti'etic aftflr beating Ijefore the blowpipe in tba reducis}; Jlatue.

1. Sviphn ten. Arsenides, ondPfioBpftate*, chiefly. —Solnblein hydrochloric or pUdc fl-cid nitlirnil a perceptible Pesidnej ek1 witbouC yiddlDi; gdatJuous silita iiiKnn evaimration.

S. srittn/ns— Soldljiii iu hydrmbloiPicoPBiti'fcacId, aniJ yield pilsiti no ua aUica upon cvuporatitin, ur af>CTiuip<js&il with the fM-'paratiou of iltca,

8. Not bcioniing to the foregoing divisions. — Insoluble in hydrochloric acid.

Part IJT- Wheti fuswl witli godfum carU>tnitei on cbarcoial do not giva a Caetiallic lobuif'. and when vised alone in the rBducin flame do not iwcfUiif magneLic.

1. Salts of the AJixtli and AtkaU-Earth Jn<:tah.—A.tt&r intense igcitlon be- fore the blowpipe, either ia the forceiis or on charcoal, the igtiited material giv. s qd a1kalin reaclion wheo placEd on moisteaed LunaertB paper.

a) Eapilr nnd completely eolublp in water.

b) ItiKoiiiblu Jn wattr., or ditHcultly or only piirtially soluble.

3. .irflfjin/cs. rhospkiites tj-nd. Hijrtitnit, cbi>f!y. — Solutilp la liyilrochloric

acid, but dD not yield a jelly or a reeidue at Hillca upon evaporation. 8. SiVcaftfl,— SoIijlilB 111 Syarocliloric iWJid, atid yield gelaCinouB silica upon eTap!>ration.

a.) \ji the closed tii\w p;lve watef,

b) la the clos'td tiihp givn liltl" or ho water.

4. Sf7ca(!(.— Decrnupo&l hy hydrochloric acid with the separadon of sUlca,

but without the formiitiDii of a jelly. la the cIiki&I hilie giKti water, b) Iu the cl<.>si"il tule giv*? litLie or no water. EL Not belonng to the foregoing divisions.. Insoluble in bydrocliIoricacSd.

Q.— Infi73Iblk, Ok Ptsisls Iboye 5.

J, Sfifi* of the ADinli-iTtK Metal*. — After InTiia litfnii ijnfDre the blow- plM. iith<?r in the forceps or on cfiarcoai. the ijmiteti nmterial givc an alkaline roaction when placed oflniniswcied turuitric [jitper,

5. Curbonates, Rv,lphiiles'. Oxides, Bifftrtix/'des and /ViifMp A ai?*, chiefly. —

Soluble in hydrochloric field, but do not yield a. jelly or teidud of suica

upon evaporaliou. Strteafw,— fiijlubie fn hydrochloric acliS, and yield gelatinous silica upon

evaporatioo, 4, aicaM.— Decomposed by hydrochloric ftCld With tboBeporatlon of silica,

tnil: wltbouc me flrtaatioii ot a jelly.

3a0 PHOSPEGTINO AND VALUING MINES.

a. Not tielongjni; tc the forotng dlTtBlons. loaoluljla la tiTdrochloiic &eid. &i bluL-ilUHHs Usis ilian tUat of tilaaa or a good quality of steel. Cui

be rioriii.chi.'d iiy a knift* . b) Hanlatttit e'luai to or greater Lb&a Uial of glBsa. Caoooti ba BCralChod by n knife.

CHAKACTEB8 OF MINEEALB iDANA).

1. NruDe. sytiOnjuia.

£. CryatAlliiiH, form and Rtruciure.

Byet'rm of r:ryst[|lliztion-

Ajclal ratlit and aiifiilar e'lemetita.

(iQiral abructure BBiorptiDiis vadetles, iaUiativQ forme, ic

Gohesiuii, ClfnaTogiB, Fracture, Hardaesa.

4, Charatiprs r&larJng to

HRat,

Electricit?,

Sljiciietjani.

5, Taste andoflor, t\. i'hemical compuisitiQa. 7, PiToeHMUCiinaJltlegCbJowpipe),

Systems Of Ckystaljjzation (Dana).

I. iBometric— S equal Jiies. at riElit anplee to each other, {Ei.— cube, octa- hedron, dtxlacaln.'ili'oiijiyrLiv).

n, Tetragfinal — a*XHfi_ TIih 2 Ijitpral azequal, tbt) vertJcalosiS longer or shorter; til] at right trj puch otlier.

m . Hsag-ODal anit nh>)iikii)t3tdr'al, 4 a.x9s\ 3 lattr&I fi. In BB-tnf} pIada at flO° rroiTi i?iinTi oth-r and a fourth vertical xia ftt right angles to Lhem and eiT.litir loojer or nht)r1*r.

]u Uiii; UexiigQUI system prppep theiti are 4 prJtiCfpal pliuieB t)t symmetry: 3 eual pliinrs mtei'SKtini!: at tiO", and a fourth UJi3f<(}Uftl( normal to thetiK aiE4<-- muclLlary plaueij liiamej lu Uiu seE (fX- ampl'ff, ftpatlie Bronpli.

The Khoiiilji>lifiii 111 siystetn iDclLdes forros with only 3 platieai of ajTiimetrj- ljilvn;ef;tln at J2li' in the Tertical axis. (Ex, rnombobe- droB— inacy forms of i:i:ilcit and tour malice).

IV. OrLiiorlioiiibiu -3 uuemiiil axps at rlgtit anglfls to each otheT-; 3 plana

t>f syniiTiftry, which intersect in thcsu axes but are all difTei-ent.

V. Moaucliiiic - ;) uiiBquai , of which one latnd axis is Inclined bo Uih

Vertical asiSi tne gUier titielies right augVeB : 1 platio of symmetry. YJ. Trldinic — SI uDeqiioJ uxeH, and thuir Intersection a are all oblique.

MINERAL CHAKACTEES DEPENDING OPON LIGHT (DANA). Kinds of Luster :

1. MeMJUo; 3fiVfnetaIHc.

9. Ada.Qiantin{Like diamond).

5. Vitioiig, (like bi'okHii glass), 4. SilnouE (hke yellow reaSni

6. ortitLgf (!lk.e elGC:oilte>.

6. Pearly.

7. Silky (the result of a Hbroun Btmctara).

Useful Tables. 331

Individualization Op Crtstal8 (Ce08By).

L Distinct, separate and so nearly perfect mloerals tiiat their proper forms may be clearly recofpiized=:ciystaUized.

IL CfHtfused mass showlDg crystal faces or planes and cleava planes, but no perfect crystals (rock salt and white marbIe)=cryBiAlune or massiTe.

DL CiystalUne form and cleavage both entirely wanting to the unaided eye, but the specimen shows double refraction when a thin section is TOwed by polarized light (chalcedony)=oryptocry8tftUine or com- pact.

IT. Sntlrely devoid of crystallization (opal aod ob8idlan>=amorphous.

Implanted crystaIs=cry8talB of uniform size tiiickly set on a surface.

Dru8y=very small implanted crystals.

INTERNAL STBUCrrURE OF MINERALS CCROSBT). .

GranuIar—Flne to coar8e=iD grains.

C(npaot or impalpable=when the frralna are invlBlble to the naked eye.

Glassy or Tltreous=no trace of granular structure even under microscope;

may be crystalline (like vitreous quartz) or amorphous (like obsidian). £Amniellar=laBunatioD independeut uf cryHtallizatioa, or depeadeafc. In the

fliBt case called bimded; m the second, foliated. FllvouB=U coarse, called columnar or baaded.

EXT£aiNAL FORMS OF MINERALS (CROSBY).

Botry4ridaI=rounded, grapelike.

MammiHary=Iarger rounded prominences.

BtaUctltlc=depoeited from solution by dripping water from overhanging rock.

Stalagmltic=Depoeited from solution by dripping water on floor of caves, ete.

TiiCaoeouB= porous deposits formed when reeds, grasses, moss, etc., are in< crusted by mineral solutions.

C(Hicretionary= rounded mass or nodule produced by aggregations of min- eral matter in the body of a rock.

FlBolitlc=U the concretions are small (about size of peas).

OSUtics:if very small (flah roe or mustard seed).

Geode8=hollow concretions.

AmydaloIds=almond shaped, deposited in the vesicles or steamholes of lava.

Dendritic, arborescent, mo88y=:(8tain8 of iron uid manganese, native copper, etc.X resembling vegetaUoo.

Betlculated. net-like.

Iumose=feather-like.

Filif<H:m=wlre or thread-like.

Acteular=Uke needles.

FBACTURB (CROSBY). Conchoidal=8heUy. Even. "Uneven. Eaithy (like clay or chalk>

£:aitlur(l

Splintery.

Vsefuz Tables.

THE GEOLOGIC SERIES, ACCOHDlNQ TO DANA. [See alea p. €8 for the syetem ojdaptetl by the \J. 8. Geological Survey.]

Ago dC Maa, or Quatemuy.

TtfA.rnmRliiLii Ag-B.

Tertiafy Period.

dTBtoceotia.

Jurassic

WcaldeD (epoOli}.

BaptilTAJi Age.

Oaiible (epoch).

IJflsIc (epoch).

Triaesic-

PermiBn.

GarbotiUeraiiB Ago.

Carboniferous.

BubHJftrlnntferoiUB.

c&.

Deviiti\&D Age, or of nsEes.

Chemung,

Barailton.

OorolCeroiis.

Copper SUurian.

Ortakftny.

Lowar HelderberE.

SoJlna,

SnuriilD Age, or Age or iDverte-

Niagarm.

1) rates.

Lower ailurioD.

Trentoa.

CftQudJaa.

FrunordJal, or CoiobrlBii.

Below tbe tiovrer BUurf coula the azoic echisU and anlte.

PROaPEGTISQ AND VALVINQ MINES.

CLASSIFICATION OF ROCK A, Igneom Bocks. K Aqueotte abd

Olaay.

Acid Olaaiee. ObaidloQ, TerliCe, Piitnlca,

Chiei Feldapar OrUjocisae.

CbFefFalilKps/

Btotlte Tot) Uti3) Hornblende (DC) (uid) AugUte.

BiotltflrorXand] HoTuiileDde.

-|-QitflH*,

+Qiian)i.

— orti.

azid

RbyoUte.

(Qimrta Porphyry.)

(Quartz

iCSXTE QBO

Tracbyta. fProphrry.)

<f%lBlte.)

[jp.

PhonoUte Craro),

Leucite PbonolJte (Tery rare).

DucltQ.

tPorphy- rite.)

Ajidevte.

FragmantaL

RbyoUte Turf and Breccia.

Trachyta TutT and Breccia.

PhonoUte Tuffwid Breccia.

Ande&lUc TuK

and Breock.

Gmiltold.

aBANin

(Pegmatite)

aaoup. (r&re).

NeptaellDfr Syenjt€ (rare).

Leucite-

[very rare).

DIOHtTB

Quiutz-

Djorjto

{Tonalite).

DkiHte.

SiO,.

m.ti&!(

W.SfW

B.Ow

Useful Tableb.

ACCORDING TO PKOF. J. F. KEMP. .folian Socks. C Me£amorpblc Kocka. Koosa).

Andestte Obsidian. Scoriae, Tacbylite,

Basic ObsEijiaD,

Plfigkdlasia.

Ntsplielinp,

No Feldspar.

Fyrox&nes.

A Series of

Bare Basaltic

Bocka.

Aueite (or) (and)

Horsbleade (or)Caiiid>Dlotlt.

Ultrsrbafllc

— OUviue.

-l-OllTlne.

.—Olivine.

+Othrlne,

Eahj

Ujs. Obd

Up.

Auite-

BasalL

Willi Neplisil- iii&, Leucite

one or eUl.

Aujtite.

Limbi]ir]te

fiaalc

Olivioe- BasaJt.

OMabase.)

DolBrite.

(OUvinfr Diaboua)

Hot readily dlstin] inhabit

froEii Bialt

vrltLoiittha.

mlcrnjsfopo. Extremely rare

ta AmviiCa.

Not readily distiaenlsh able from BaaiUt.

Sxt-remely rare In Ataerlca.

tlons in nominl MagcnoB.

Meteoiites.

BaBaJticTiiffiUid BrecciaB.

Water.

, QjUIBRO obcdp.

Diabase. Gabbro. Anortho-

OliTine- Dlaltsae.

OllTiae- Onbbro.

TlieFailto rare).

PjTOXeD- ita.

Periiotite.

Icq.

Nod to.

OHyine- Norite.

B6.40r<f

4E.9O0

3O.0Ok

326 PBOSPECTme AND VALUING MINES.

THE nONCIPAL

Grand Divliiong.

Origlii.

Structure.

Hatwial.

Znocdiermit State.

AqneouB

and JWoUmi

(the latter

only Btightly

stratified.

of fine

materials

usually not

compacted).

More or leaa earthy.

Arenaceous or sandy.

Band.

QraveL

Shinirie. 1 Rubble, r

Tolcante f rag- menta.

Volcanic aafa.

Stratified.

Arfftllaoeous or clayey.

Hud. Claj.

Calcareous or limey.

Ooce. Chalk. Chemical pre- cipitate.

Metamorphic

or

TransitioQ.

Aai.eous, with subse- quent heat, pressure and chemical agencies.

Roughly

stratified; is

part crystal-

une; usually

flRHile.

Useful Tables.

aOOKS (LE CONTE).

Campacted State.

EBBential Cotnpanenta.

Hc'UiarliH.

Sands tOT!B,

QUica often Iron oxida.

Orit.

Small pebbles {mostly quartz) ce- meDted allies, and iron oxide.

CoDErlomtrate.

Lar pebbles and bowldera similarly i;emDU.'iI.

BtbccLb;.

Angular rrairnients(iiftuaUyTolcaQic)

of vajloufl roelcs, cemeoKd fBitti

Blijua aul icon Oxide.

FneToIcanfc dust 'Compacted undBT water.

Shale,

Indumted particles of clay, mitially wJib BQOie quartz grains and

LlmeatoLS.

taUine'.

Migtjesi&fi IStn*- 1 Etone, dolomite, f

Dolomita and caldte.

niagBeaite.

Uagneslte.

Gnelaa.

MJca, quartz, feldspar.

TSiia. achEst.

Mica, quartz, feldspar.

Chlorite BcMBt.

Chlorite', quarts, (eldspw.

Tfilcose acbist.

Talc quartz, feldspar.

HotTjbleode schfet.

Homblebile, qiiaCtE, felddpai-.

Qaruet Bchiet.

Garnet, quartz, feldspar.

Blate.

Hardened atinCe, cleava acrosB fitratlAcaEioL ploiids.

Quartzito.

Alterbd BaUda(ob.

Marble.

Altered Umeatone, caEcJteu

Serpentine.

Altered m,agnetiian minerals.

328 Pr08Pecting And Valuinq Minss.

The Pbincipal

Oruid

OrlKlii.

Sbncture.

XateriaL

Oocurrence.

Phitonic or massive.

OcCIUTlSff

nwiHirff

OccurrlDfr In

Uoitratlfled.

Igneous.

CiystaUine.

IntmsIoiiB.

Volcanic or

Occurrlnff fa

true eruptlves.

overflows.

Besides the essential componeDts there are tnauy minor " accidental " morphic— su( as magnetite, pyrite, olivine, etc., but these usually occur in

USEFUL TABLES. ROCKB (LE COTTTE}— (Cim<iiie((-)

Compacted State.

jdClDCC—

Pegmatite (apblc

flranite. EuTite or grnullte.

Quartz syeuite.

rorphyrftic granEte

Basic—

Dtorlte. Quarts dioHte.

Qabljro,

Quart* poiphyry.

Fel&ite. Di&rlte.

iCIDIC—

Kbyclite.

Tr&carte.

PhonoMte, Light colored

PumlcB. ObeiOiaO.

Andegite.

BaaalL Tachylite.

Large plates Of inl4 fmbeddQd

feldRpar.

Quartz, crthdflwy fi.'ldapwf. miCfi.

A nue-traJiiudjifr&iiiie. Ortboclsiatr ;', hnrubleade. Qtiart:, ortho<lfiAB ftild&par, born- blonde. Large ciyatn.ls of feldsp&r la a fluur grnu admass.

PEaEioclaseCeltlstai', IbortibieDilfL

Piioclase ftldspar, bDmblende,

auartz,

PLagJoclosa feloHpor augite, Olivia's

Xrtmitotd sartety at aiabase).

ftI£croc[76talIlae grrouadmass,

IflTEcr crystals of

ortliooLUM ixivi quartz.

MlcrocrysUls of ortboclEiae and

quartz.

FlofliKlaaa ana horabltinde (micrD-

cryntalUDe).

Aute aad bombleade (microcxyH-

taniaib).

VUreDiia groundnieisa. witb crystals

of quaru %a tirthoclftse

laaniidiTi).

Vitreous Erounduiuas. wltji cryetal

of ortli'x:la&,' (sanidiTi'i.

VitreouB efouadmaaa. wlib ffystCLls*

of aiidia acid, uepbeliae.

TitreouB Erouadmaas, with cryatala at plaglocuue, auito orlwrableuiJe.

Vitreous Kn)uiidma£B, with cryetalti of plagiolase, augite and oIlTiae.

Mi crocry KtaEUoQ

groiiudmasfl, wittL

or without

larpfP crvBtals

iaibeddfMli

Glany £Toiind- uiQsa, with fine to CDarue cryijtalKim' Iwdded, or wholly vltreciuH, Uaijally ft'ifKrained (micro- LryutalUoe) ot- iu- peifectly cryatal- [iji6 (crypttKiiystftl- IjuoI. The CoilowJng t-xjt. ia the fltouy cndUiUoB;Phyollte, lipur!t<ti, trachyt>e,

d<jlr'rite and aade- '. The fullowia areglasajr: Scorin, puimce, ob Bidlan , and tsiuiyUte.

or accesBDry minenils ia moat rocka, especiaUy in the leous and meto- RDoll proportjous.

330 FBospEormQ AJHD VALUiNQ Mmm,

CUEAVAOE (CROSBY), KJodfi:

la the Kometric{1.)B7atein, f Cubic;, octahedraJ dodacs

— tetmtuil (U.) flj-HtuiD titdraL, etx:.

— <jirtiiCKrboiiibic (IV.) Fi3'aU;ni- priamatie, basaX and

— mooocllnic (Vj BjHtetiK piDflMwldaJ / pynunldal.

—tricUnlc (Vlj Btem ,) J

Defrreea :

Perfect or emlaeEit (like inkaj.

Distinct,

ludifitiDct hagiext&iA.

In traces.

MUTERAIS DISTINOUtSHm) ACCOEMNG TO TOIJCH OR FEEL (CROSBY).

Meacer (Uke clialk, clay, etc). Smooth.

HArab. Unctuous,

Boogb. Greasy.

UINERALS DISTTNOUISHED ACCO&DINa TO TASTE {CRtBT).

Astritigat. BaliDtf,

Cooling, AikftUne.

Bour. Adhtialva, Bltler.

MINERAig DISTI¥r0UlSHi:p ACCORDINQ TO ODOB (CHOflBY).

Swilphuroufl, Ai-IlaceoiiiB (IfLu ).

Araeulcal (Ilka Fttrlic}. Fetid Q\k% souie lEinegtOQea)

BorgeruUsta tselenlmu).

Scale Of Hardness (Mohs).

1. tfoUated), rery soft.

2, QypBuni (conitact alabtfr), can be scmtclied by bba flnger luUt a. CMelte, can bo urusin'.! Iiotwwn the teeth.

4. FluorJte, eaH[ly ecnitiln'cL hy Jiulfe elel. G. Apatite, about tli*; liuJxluis totfe sijinL

5. Feldspar (cirtlicn:lla>ii.'J, ejisily Bcnvtclied bj' quaxtf. ?. Quartz (ciygLiiUltift), iKratoIipri onHury glas. 8. Topaz, easily Bcratchtrf quartz. H, Conindutii, scratclied odIj" bj' flfumond.

10, Uiaui'Giid, burdtt miueiraX kacjwD.

T>r. F. M. Eudlloh says: "In testing the bardoess of a minenJ fcy tbis nc&le, care abould tikiu r\iw tlie pure ujueral, not a mixture, la obtalaed. irRinlnpr&l BCratcliea ctiicit- , liut Is sLTBti.'h<sl bj' HuriritB, Xa fitiout the same deifree, ila hunlm'SH lies uearljf midway beTW'Seii fi and 4, aud la exprenaed by S.5. If It barely Bcrtitches (lc;ite, but in dpciriw'ly scratilieil by fluurite. the liardaeaa Is a.5; If uearer to fluoriteln hardness, but bIJU Bcrstched by lt tbe liardno ia S,& — i.""

Useful Tablkr

VALXraS OF METAl-S, OHFS, IHTNEBALS, ETO-

[QuotHtifHiB ttrethf'se ruIlDtf la thp UnH:fl(l Statea January J, ISffiH, ThS BelUnK poiuti when Dot Othtrnvisu . ia aasuniiHl ia be New York City.]

BubGPtanoe.

Non'-klETALLIC.

Coninduui -..

DJAtunsaiiwO'iiB in- fuatirjal earth.. ,,,.

ICuiHry

Garnet...,...

Grindstones

Quartx

KciiiteaBtoDe..

KoitRe

Tripoli

JUuid

AluuiiDiica Bulph&t ABbestOB.-.

Aspbaltuni .

ABphaltk: UmOfltODQ.

Barytea

Bauxite

BJtumim

BLcuniinoiissaudiitODe.

Borax

BiXiniSnfl

Ojintml;, Baturol hy- .:

Cemestt PorElaud

Cement, elaf.

:

Obrome ora.

Unit.

Clay, ohlott...

Clay,flre,

Coal, antliracite, eWve

Cool, bltumiD'OUH

Cf*lt cannel , ,

Coal, lignite..,-.-, CiJuailsviUe ,..

Coke. Trialdod

Ciq>peras

CffppBT Hiilpliata.

CryeLlle —

Feldspar

FlJut, slLk;a

Fluorspar ,,.

fe'uller'ii earth

Lb,

I/Dte toti, Lon ton. Ehcrt ton. Short ton.

Lb, Short ton.

Lb,

Lb.

Short ton.

100 lb.

imib.

lortton.

EborttotL.

Short toiL Short ton. Long- ton.

Short' ton. Lb. Lb.

Bbl.

Bbl.

Bbl. Short ton, Laia too.

GhoTt ton,

Short tan. Long ton. Short tou. Short ton. Shj>rt ton. Short ten. ShorE ton.

Lb. imlbH.

Lb.

Lb.

Short ton.

Short ton.

Sfinrt ton.

ItlOLb.

Prioe.

4.6-lOc.

la.BO-SE.lB

iT-aoc.

l.CS

1.25-1,76 19. Kf Ib. Hi

4O.0O-eO.OO

7.7a 10. oo

S.ttH.SO

SSe.TG t],7ES.60 2,0(l-,iO

HeiQapItB.

Be&t ground Qru(3e Naxofl.

Lump. Lump. Lump.

Lump.

Beat Cuban, Lowr gvadA, Trinidad. Utah EilaoniUi.

Cnide. Beat.

Crystal and Powder

Barrels of 800 (Im. barrels of 400 lbs. Barrels of .1 Vh%.. Oouimerdal lump.

j£>oiiLestfc r. D. bat

1 works.

Brat

ScroDtoD, Bk

FiEtaburK.

Denver.

Pittflburtf,

Denrer.

Beat ade.

From Qnwoland.

OroiiEd.

Lump.

CYudiwt

Lump.

Useful Tables. 333 "

VAXUES OJ" METALS. ORES, MINERALS, ETfl.— CtanHavfrf.

autfitance.

Iridium

KlclcBi

Pladtium..

Quicksilver

Rilver

Rake Elembxts. [prioei Iflva are at

nLBkerB' works is &er-

Tnanp, unlees otJier

wlsencted.] BtLTium — Amalgam ,,.,

Elfctrol

Beryllium — Fowtieir. . . .

Crystals

141trate., fioroa—

AmDrphDua, pure..,.

CrjstiJs, pure

Nitrftte. , ,

{'aicium — Electirol. Cerium— Fued

XitrBte

CbrooUym— Fiifled,

Pui-e, powder

Cbe-m. pure crust..,. Ciibalt— (I@9g:C>.

Ripe... ,

IMdj-miuDQ — Fowder. -.

Nit.ratd £tbium..

Nitrata nallium.. Crmnnlum— Powder. .

Fused

Qluclnum— Powder . , . ,

CrjEtalft.

Nitrate ,.

ludjum r

Lab iJi an um— F [>wdisr. . .

Electro L, in balls

KltTftta ,

Lithium

IlErate.

Molybdottum— Pd wdar

Fused, eiectrol

Niobium

pBtnlnin -

Faibtdlum— SpoBKs "

Stieet and wire

Gram. 100 lbs.

Lb. Troy 02.

Flask. Tray OB. LoQir WD.

mva.

Gram. Gmm. Oram.

Oa.

Oram.

Qrom.

Lb.

Lb.

Oram,

Lb.

K*r.

Qram.

Kg.

Kb.

Gram.

Oz.

Gram,

Oz.

Orala.

Gram,

Oram.

Gram,

OreuD.

Lb.

Gram.

Grain. Or. Gram. Ox,

grams.

Gram,

Gram.

Oram.

Qraxa.

Sl.i9 3,TS

$14.60-16.00 41.00 H

Sss.oS

K.Oo

Si. 19

5,?1 5,fl5

£.60

fl.ffi l.SO 4.S8 a. OS 38.UJ G.fi& 1.7B I9e.

S.Sl S.09 3,00

S!l,32

a. 50

4,58

£1,50

2.Sb

eoa,

t2M S.SI

ate.

1J5C. Si .To

Bemajsa.

Erice in Qermuiy. Sew York. Accord'g CO quaatltjr.

New Tork; flaak dt

Com" value,

PlttHbUtB.

New York.

New York.

New YOTk. NeWTOtfc.

New York.

New York.

New York.

New York. Uaw yorit.

334 Jpb08Psctijhg And Valuing Minb8.

VALUES OF METALS, OKSS, MINERALS, ETO.— Cbntind.

Substance.

Unit.

Prloe.

BemarkH.

Gram. Gram.

Gram.

Kg.

Kg.

Kg.

100 grams.

100 grams.

Gram.

Gram.

100 grams.

100 grama.

Gram,

Lb.

Gram. Gram. Os. Gram. 100 grams.

Gram. Oz.

Gram.

Oz,

8.S? 11. Do

7,50-6.00

JHSc.

Si. 19

7,14

119. Uo

Si.Oo

Selenium— Com''r Sublimed ixiwdei' Sticks

Siliclum —Amorphous. . Strontium— Electrol,. , . Tellurium C. p. sticks

Thorium-

New Tork.

Wolfram —Fused

Lump.

Nitrate

Tables.

Mf

u; — 13 — — :! 1- a

ia£'

Ot HtlfVJO

II It i:| II II W 11 II II

IBej Bjwnbfi hSjfeSSSSffi

Useful Tables.

The oalj material standftn] of CUatOmaiT- leHElIi authorized by ihe IT. 8.

the britieh tondaird. The yiu in use iu the Unit Stales is therefore wjuol to the British ya,rd.

The only Authorized mateiial atandafoE of Customrtjy weight ia the Troy pound of thi Mint, it is of braHS of unliniwn dnsitji', bhI therefore not 8uilabtf<:ii''fktiiridiLMof Qias!, ]t waA ddNvid Itnui tlie BiHtliU sUtqdarU Troy pound of 1758 by dirt'ct. Koraparisoa. Tht? BrEliali avoirdupota pound W&s alsa (Iprivtd from tha lAttar, and contain!; TOW grtLlns Troy,

The grain Tro' Is llmnrure tlio Bairifl as tha gfuin avoirdiiiiois, and the [)Ouu>1 abofr()u[iois in use in the United tatoB'iH equal to tbe BHtlgh pound avoirdupoiH.

British jrallon 4,&i3-l6 htora.

the Rritinh busdifl 3B.iM77 titers.

Uy iht' ioricurrenl luitioo of the prinripnl Qovemments of the world an luterutuiuiiid Uiirfau of VVeiihts iind MtMuiureH has b[£m established ueor Piuis. Undr the direL'tion uf th lat-ernmiooal Committee, two ineotia were cast of puif platinum i rid iu 111 in rlie proportion uf D parts of tlie former to 1 of the latter nietal, From one 'if rhese a oermin nutinher of kiloenmiB were ppared from tlie other a di'tlnire niiinUfr uf iritt'r hivvs. Theeu standards <jf wiight and length ware iiiteiconii'itr-dt ta itiiout pnreretict?, AttA certain onea wcru seluleJ 4i£ InttrniitioiuAl yototype taiidardE. THo otlicrH wei-e cUstributid hy lot [o Che different i(Javmniiignts and are called National pro- totype BtAudflixta.

Tbi3 metric Bvat-em was leaSized in th* United States ia 18G6.

Th Iiitflrtia,lloua.l iijtaudard Meti' Is dRrlvd rnmi Mtre (Irs ATohlvfia, and ita len'Th Irt detlnod by ttiB distaocx; b5tweon two liuoa at Centifrrarte. on a

SliLttnuiii-iridlum bar deposited at tlie luteruatiiDDal Bureau of Welghta and teasurefi.

Tbe in tenia U on al Standard KilQraiii Isoi mass of ptatiuum iridium depos- ited nt the same plat-e, and Its weight in vacu*} is the some as that of the Kllorauiine des Arehivea.

The liter i-i equal to a. cubic decimeter of water, and it ia. measured by tha quautity of dlstillenj water whichi at its ciaxinmiri tlensity, wjU coimterpolw toe Btbiidard kdoram in a vacuum, the volume of Huuh a quantity of watet bein. aS aeady otj haa ecrtaued tua! to a- euWo decimeter,

Iion tOQ: 3i4D lb. avoirdupois — 1016 klJoeram, Short luu: :ii">0 ' " 60T.3

Pound avoirdiipota 4K).6 jrramB.

flask of mercury =7flX lb, aToJr.— 34.700 klloeram, Troy ounce SLKMertuuB.

Gallon 3.785 Hterp.

Barrel of petroleuta 4Si

" " SKll: 280

" limB 800

" natu!%t cement aoO '

" " Port]B.;aiieQt - 40O

Gold coining ir&lu per ax.. Troy $30.fi718 Silver ' '' Troy - IX.HSa

fol. 1.59 hectoUtr.

lb.

127 klloftram.

181. 4*0 "

==|D.tMlB7" "

Good Books Of Keferench._

[Any of th? fDUowlng hooks cao be nbtairi'ed at liB't pricsE, carriaK nreDBM, from Tbe EuigiiLeBriuir aad Mmiu JoumaJ, Jl Broadwur, New VorL, U. a A.]

Absatinq.

ABBaysr'sOulde. By O, M. Llehcp ,... 1.60

ABJiAytr'a NauiiRl. Uy finiDoKBrl. 8.00

Assnyiini;. By C. H. A&n>ti, Pan I., Golditnd gLver Oi'QB. fl.DA

lu-ce II. and HI., UoLd und Hllrer BuIUoq, LeexL, Oopper. Tin.

JUercuiy , ,,.. ],76

AisayiiiK. A Tuxt-Book tin. By C. &.J. J. Btringer 9.SS

AsaayiiiE'i Manua] of ProcUisaL By Jolin TilitobulJ ... ,.,.,,., lOM

AHBayiiiK, Not*;s<]n. Hy P. deP. Rickettaand H. Miller.. B-flO

Asaaj-ini; uf j julU, Copper, Silver, Gold and Mercury. By T. Bodeniui 1.50

AfcaayfaK Witti ilie lilukvpipe, Qiiaiitilatlvt>. liy Ji. L. Fletcher I.fi0

Practilcal Mutallury and Aswayin, By A. H, Hioma.,* I.M

MttDual of PrAcuiyal AHBaying. By H. Vaa F. Fumum.., 9.00

ManiiuJ of .sH&yiii. By W. L, Brawn ,,, 8.fiO

and B. KePl- ,,..,.,.., , I.OO

Alkali Maker'a Pockeb Book, By G. Lunge SW

Alkali Manafjuirupu in <Jreat EH[Al, itt . n. Of " Tlie Mineral la-

diistry" 9.00

Alun and Sulphate of AlumlDa. By Jolia £ntiijUisC, Id YoL m. of " The

Aiintral Industry" 6.00

Briefer Ojurso io CEiemiscry. By ira lieniBeD 1.18

Ch(.<iii>c{il AualyKJu. By 1>. O'BrfuB KOO

Cheiiikral A.Trnil>sis vt Iitiq, Et A. A. Blair *,00

CtLoi;iiH.:al Aimlyii.i3, ijiect itilHtiiods in. By Win. Crooks £.00

CliinilL-al aini Mrfallurgicai Hftndbook. By J, £1. Creiner and 0. A,

Ej;kl"ll. ,,.,.,.,., ,7B

Chemical Tiiijhnoloy, By C+ E, Grovetj aJidW. ThoitW 7,B0

Chemical T'irhnoltjgy. By R. Von Warner , 7.6ft

Cbiiiitry for En'Inera and Mauufoturem. By B. B)£int aric3 Q,

Bloxiiio. Vol. 1.., Chemistry and Ennfffirici;, BuLMiit and Mftbal-

turjfy 8.50

ClipmiKtiy, PiiDciplps of. By D. Misnilflfr ., lO.OO

Di-tioTiary of AnpHod Chemistrv. By T. E. Thorpe Vol, t. (A-Dy),

SIB-OO; Vol. n. lEaii-Nujtj, SlS.OO, Vol. III. (O-Z), fSO.OO; coinplBla.,. 60,00

EI!iro-fTheiiii(!Al AjiRljpsiH. By E, F. Smith ...,, i.iB

EJectroCheinihtry ami hUeitrci-iMetallurgy. By W, BurclierK. la Vol.

IV. of "Tho JJlinornl Industry' 6.00

Elec tro-Cheuiiafry. By (i. [Jore ft)

E!*otro-Chcmistrj-. By 31 ix Le Bln.Dc ,,. J.SO

EitjL'lrotyslB. By H. FontBine, ,t,.,, ..,, RfiO

Edglntjerlne Chemistry, By T- E, fSXiUmti ,,,,,.,., 4JS0

InduHtrial Ch'.'mlslry. By J. PayuQ.. 10

Inoraan'c Chemintry for Beeliineire. By H. E. BofiCOB and J. Liint.. .. , .75

lAhnmlory Mftnusl anri Pnn.i.'ip|43 of CnemisCry. By 0. H. Bitihardson. ],10

Laboratory Manual. By Ira Bemseu ... , .40

Good Books Of Reference.

MetflUiirRicnl Analj-Bis. EyN, "W, Lord ..,,,... l.SS

Poiaaaliiiu OVtiDiile MunuEacture. By TitUB Ulke. In Vol. rv. of "Tto

lineral Indiiisrry " ,.,. ., , 5,00

Quiilitatlve Aual}-Bi, KotescD. £y W. P. jnosos 80

QuiUitative Clioinical Aualyefs, A Short Course Id. B. C A. Schaeffer. l.SO

Utiatltativ-e Olieinical A-cnlysis, Uy F', Clowes SLAO

gtialitAEiTi!! Ohprniiail AnaljiBbi. By C. B. FreaeBhia ,. 5.00

ULialJI&tiv'. LIihilIuilI AiinlystB. by A, A. Noyes, 1.25

QualltuiivuCli'iuiii'iLl Aualysia, By JoJm Mfller. ,.,,,,,. ].&0

yuaiitlUi(.ivf AuaJyHis. By H. C. BdltoU. I.fiO

Quaiiticative CbeiuJL'al AnalysiH. By T. E, Thorpe.,., ,, J.ftO

OurttLiiifltlvfr Cli.-iiin;a] AB:Ll_vsi liy ElfctJ-olysia. By A. CUbkti .,-. 8.00

Quantltiitive; C'hciiii(inl AiiHlyin. By II. P. TalYiot I,&f)

QuactitiUive Ch(3miiyil A nlj'sfn. By C. R FitenfuB. ,..,.,.,,., ft.W

bii]t8, Tublt:? aud QiLu.utLtiUiiVti' AnalysJB. ByU. 31. Fattlson Muir,. GO

ilu]pburiL Acid Mfiimfacture. By (iei>. LuDj£;e. S vols. 85.00

Vcjmnnlric ADaly>ili*. By H. W. BbJmpf 2.50

VcdumeCric Analysis. liy y. BbitLDU 4.&0

ELECTMCrTT.

Electric TVanmfeBion of EneiirT. By G. Kapp, 3.S0

Electrit;TraDnilsaloii HuiKlbook. By F. B. Bitit 1.00

Eleocriojil l>ist.nhutii)U. By M H, Kiigour, H. Swao and B. H. W. Bogs 4.00

Eleccrin;al EnRiucermR. By W. tIino and A. Brookei 3.50

Eluctrk'al lneiii.-rriufc as a ProfuBsloti, By A, U. Southani 1,25

ELi;i:trical Toukift-Book. By G. Munro p.tiif A. JonneBoii S.50

Eltwtriciil IV.HTr TmnKmJH&ion. By L. BhI) 8.50

Electrital Transirieaicin of EuerEy, By A, V, MjIioh,. „., 4.60

Elffirriuiry ami Watt?r Power. By M. A. KcploKlu 1,00

ELectrkity f&r EnginMrH. By C Dtinornl, ,,.,..,.- .., 8,60

Electricity in taiaiug. By S,T. TboiniisciD flO

Explosives And Blastins.

BLBstiiiE. By 0, Guttmann 3.75

BlAiiiiibjf anci (juarnin. J. Burjoynu 00

Blasting in Mines, Quarries. Tumiels, i?re. By A. W. EiEd Z. W. Daw B.OO

EsploBivtw and Their PtiTvera. By M. Efcrthelot 9.75

Explove and Explosive Gompounds, A Bdef Primer of. By M.

Bprthlot 50

Lectutt: oij Explosives. By W, Walk? , ,.,,...,,... 4.00

Hnderii Bljili SsfiluKlves. By M. EiBsler i.OD

Kitro-tixploBives. By P.O. SatiforiJ,... .,, SHH

Itocit Blasting, ByG.G. Andre a.H

Geoloqt.

ABptxrtsof theEatth. By ET, S. giia'r ...,,.,,.. „. ¥,M

CheiniLa] and Geolocai Esitaya. By T. S. HunL.. S.Bd

Economic OfHiloKy. By R. S. Tari- 4.0O

Elflnientary Oi'Ploffy- By R. 8. Tarr 1.4I>

EliMJiyto Mf f.Jfsiloy. By .1. LeCoiite 4.00

EuBlnwn-ine l-Jeolupy. By W. H. Pt<nnJiiE 1,40

Pfcid Cii?>Ky. By w. H. Penning ],40

EJpId tJcoloity, OiitUnia of. By A. Qefkle 1,00

OtuHtis of Ore ti*jnisiia. By F. Poaepny 8.00

Geological Story Briefly Tuld. By J. D. Dana 1.16

Geology. By A. J. .1. 1.00

Qeoloky, By .1. Prestwlch, Vol. 1. Chemical andPliyeioai O.SS

Vol U, etnvtis-niphiMl anrl piivHioB4. ,c ,,. 8.00

QeoloKy. CloHts Bi-okof, By A, dnWiifi l.IO

Geoloey. CoTni)aratlvif. Trauslated by p, Lake .., ,...,, ,. 4-S}

CrfioioR-y, Compend of. By J, I*pConto 1.30

Oeoloffy, 'ewTect-Bol)h: of. l!y J. D, Dana JLOO

Oeology of ColotwJa&Bd Western Or Depilts. BG. Lake S.bC

340 FHOSPECrmQ AND VALUINQ MINB&.

GpoWgy, fra<'Mral Aids In. By 0. A.J. Col..., , ,,,. 8.09

Geoloiry. Priuoij.lrttor. EyStr JuhB Lyel] 8.00

Ocolojjy, Text-Book of. By A, (fftiki* T.bO

Hanri-Boolr of Ftocfca. &y J. F, Knp

].i me;* tones ami Marlilcs. Dy S. U. Biimham , Q.OO

].irlinlr.ey, MnilRlof, By B. H, WJltiaunS ., 3.00

Mammli of Qwolow- Ry J. I>. r'ana ,., 5,00

'Ijeti Air Studios in Gwleicy. By Q. A- J. Cote 8.00

lire He oaila By J. A. Pliillirw 7.00

Ore I>eiiti6it!itif UioUiiilodBtat-s. EyJ, ¥. Kemp 4.€0

(Ire l)i]MiLs, Fonnattou nC Eruptive, By L H. L- Vogt. In Vol. IV.

or-Thw MJDHr loduBlry '",, , ... &,O0

OriKin of Urea, Viewa Held To-day. By J. F. K&mp. In YtA. IV- of

'Tlii-Miaera] InduBtry 5.]

Hfiolway tiuidi. Ao Aniiu'ictu) Qeolovlcol. By J. Uacfarlftne 2.50

BockK ana 1116. By H, E. Bloukbridge S.ai>

Metallubg -General.

Alumiaum. By J. W. Riclmrda fi.</i

Alloys. Tranaktl4LDdeilJt<l iiv Wm, Brant 4.1ift

AJlnypnnd Their Constit?nta. By R. H. Thuraton p.. ..,+ 2.SW

Ai;i;eDl:ireroua leHii Orej4, TrtiLtmeitit of. By H. O. Hofiuaii. Arlides

(in f hlfi siiTnrt't flini wntfliriffd in Vols, I., U... IH., IV. aad V. OC The

3Ilni>i-al InauHtTy " eat-'h SjTO

Ooppffnij-lilUH. MiyJeru. By Kitwiii'd D, Peters, Jr,., .,,,,, ,.., S.00

OOprierSiiiphiitM Maniifjictiire ftt Frulber. By A. Dopit. In Vol. Y.

of " The MiDorhl IndufiiLry " ., . BQQ

Electro-Chmniiitrr lunl KlfjcTm Metallurgy in I8SJS. By W, Borcliera.

In Vol. V. of -The Minnirfil Influatry." S.M

fclettro-Cheiiiiiiitry anil EiwLri>-Hetlliirgy, PrOKress Ui ISBS. By W.

Borohprs, In Vol. IV. of The Mineral Indugtry ".., 5,00

Etectro-Metallurgy. By A, Watt 1.00

ElwmilMeUilliiP'y. By (!. Gn? 2.00

Ui&etro Mi'Uiliiirpy. By W. fi. McMlllau 8.B0

T..eail and CiiiJr>er Sm+ltinpand L'iiujmt Converting. By H, W. Hixon.. 3,00 ' Lewli Metnlliirg)' of, anil the DisJlverizatian of hwa GiuIJon. By H. O.

HofiimD , , , ,,, B.W

Lead Bwrsiug. By J. E. Rothwell. Iq . IV. of "The Mltierallo-

duatry'".. , „, S.OD

Matte SmellinE. By H. LRng,.., .,..., £.00

Mdt&lA, Tlir PropeE'des and Treatmeat. By 0. Bloxam and A. K.

HiiuUrigt.jn , ,,.,.,,,„. 9.001

Metalliferous Minerals and Mining. By D. ('. DaviDS 5.00

Meta!lurj<y of Tin. Bjr H. I.rtiiJfl. In Vol. V. of "Tbo MiDerftllnduatty.'" 6.00

MetJillur, Iiitrodiiction to thttStmly of. By W. tl. Rotorta-Austen... tiW

Memllurw. Elemcctary. By A. H. HJoms,... 1,00

MfUUurgj-, FJtJuiPntsof. By J. A. PhUUiJS 9.fM

Metallurgy Asayinff, Bv A. JI. Ilioms t... I. BO

Mill Prautiiw in California. By E. E. Prswton 1.00

I'lojn.-BS in Ore DrraHinE in 1890. By It. H. fiJcharda. In VoL V. of

"The Mineral Industry"... 5.00

Rare Elennnle. By L. M. Detmla, In VoL V. of "The MiaeraJ In-

diiHtry " 500

Recent ItnrihiTetMenttt In Ivftod Meballiir, "By H. O. Hofmou. Iti Vol.

V, of "Tlie Mimirat Industry" - 5.00

Rejjeiipratoi' Furiiatiefl. Ev M. ilrahajn , .,,,,..,. i.ffi

ZlnciLiidCadiiiliini. By W. R. Ingalla. In Vol. V. of "The Mlnoral

Industry." 5vOO

Zinc iteHnlMg. By BruDoKeri In VoL V. ol "TliaMlaeral Industry.". 5.00

Good Bookb Of Heference.

METAIAUKaT-GOLD AND SILVER. Amalgamation of Free-MiUliiE Gold Ores. By L. JbdIh, Jr. Id Vol.

m. of "The MiTitimllnduatry.",. ,..,.. fi.06

Barriil CIilDriuatiaa Proctsa. Bj- J. K RothweU. In Vol. V dt '*TJie

Mio*-ri4IiidiiJ*'ti'y" , -,.,,.i..,, ,..,.,.. fi.W

ChlDrlxliziug Hoaetlrig of CalcarKous ver Ore ContaJning_ArsanfC In

Lrftfge Qiianlitiefi. By 0. Hof menn. In Vol. V. of "TheMiDeral

laduBtry.",. fi.OO

Cyaolde Pruc<iB. By L- Janto. Jp. In Vol. I. of the MintirallBdUBtry." *.M

Cyanide lYfHMiBS. By A. Sdieidel l.M

CyBhld© FK>i!eiB. By-farkij ,, , ., 8.™

Cyanide Prfwera. E. B. Wiison. l.M

iCiy&iiIdfi Solutions, PreclpiratioD of Hold from. By W. A. myalls. In

Vol. IV. of "The Mini.i!Ll Itidiiatry.", 5.00

Gottlntf Gold. By J.C. &. Johnson, I.SO

Uold AmaleomatloQ, L.nist-s Id. Ey W. MiDumiotL and P. W. DufQeld. Si.(Kl

Gold and Silver Ores. By Wm. HiunikoQ ilerritt.. ,...,... + .TS

Gold ChLorlnatlQu. By J. E. BothweU. la I. of " The Mitieral In-

duatj-y. ,.,.,,..,,.,, , „ SJO

Gold librtractionatthe Witwatesrand, By W. H. Feldtman 1.91

Gold, Metallurgy of. By M. Eia&ler.,. ,...,. 0.(10

Gold. Metallurgy of. ByT. Kirfc Rose S.BO

Gold Milling. By H. Louis. SJSS

Gold Mines of thiHfittd. By 1>'. H. llatcii and J. A. Clialmera..., B.M

Gold 01*8, Notes on theTtvifltiiiC'iit .if. By F. O'DriBColl. ., , *.00 HydroMeiaUurKj' of the Pre4;ioii Mttala. By Heary Wuna. In VoL

V. of "Ths Mineral Industry "..„ 6.00

Loa'hinKofGold Sliver Orra. By G. H. Aaroa 5.00

JJilviatiouof Hllver Ores. By C- A. Htetj&fflJdt-. , .„ fc.OO

OreRoaatlnff Bj- Kui!;el E.OO

parting and RuHnine Crold and SUvm- Orea, ByT, Dike. IbVoL, IV.

of 'Tlii=' Mineral luduatry.'" £.00

Silver. MctalliirCT 'J'"- By 1*1- EteBler ..., 4.D0

Boutb Africa, Diamonds Bcd Gold in. By T. Keunert a.0*

Stamp Milling of Gold Oreg, By T. A. Hicfcard... &B0

VukouGuldiFitildd'Ciuide to. V. WUboq .70

MUraRALOOY.

Blowpipe Aualyais ajiil ItermisatiTe Mlatiralof. By F- U. BadBcli. . 4.00

UliDWplpv AUalyaift, Hy J. fjitidauar .i,,... ..m , + ,,.,.i I.IJO

BlowpLpi! in €hiniitry. MiiiteraluEV aud G)Iogy. By A. Ro4s SOU

pet.irmljiaticiu of Rock- Formlnj? Minerals. By E, Huftsack, „..,.,,,,,, S.OO

DtteriJiiiiative, Bliucruli;y. By C. G. Wtifteler . IJB

OBtnaand Frecitiiis HtoniVs of 3 Auieriiia. By O, F. Kuf ..„.,.„, 1(X00

Hwd Book ut ftucka. for W'LthiiuL Llm Mkroaoope. By J. F. Kamp. Lfib

WJoeialogy. By F. H. Hatol* ,.. ,00

Ulneralogy and Petrography. By J. I>. DaQB S.OS

Hlncraloeyj, CirTstaUorap and Blowpipe Analyala, By A. J- Mosea

aodC. L. Paj-BiKLB. . . . , . . 2.00

Mlnraliiyy, DwcrlptlTe. By H. Baueroian .. S.UO

Mineratotiyr I>?termiaative. By Q. J. Bmah S.60

Hin>ralo', EHm&nls of. By J. Niool.. ,...i --. iOO

MiKenilogy, Hn-ndbudk of. By J. C. Foye ,B0

MlQfralogy, Niv System of. By J. D. Dana. ,,,,...,,.. ISJAj

Min'emkigy, SyUiiiiatl. By T. 8. Hua&..,. fiiOT

Minemloj, Text- Book of. By E. S. ]>ana ..,.,,,,.,,., .,,. SiB.

MinrfLlA. CaiiilopUG of American r..oca1iLfea of. By E. S. F bmjL ., i.Off

MlneralA, Catalogue uf, and SyDHSDyms. By Thoa. EgLesn, ,,,,,,,,.,, S,C4

Hln4:rals, Uiciiouary of Names of. By A. ft. Uliete}' S.SO

Uuw Co Study Them. By £. Daoa.. p „ LU

342 PR08PSCTIN9 AND VALUING iflNES.

PetroloKT. A Text-Boot of, ByF, H, Hatch M

TAbles for the Itetermlnation ofUlncrala. By P. Frosr.. 1.50

Mtstng.

AcclitenU. Mining. aiiiJ their Prevention. By Sir B*. A- Abel

Amcrlonn IrlJniDg Code. ByH. N. Copp

ADtiirn tt<- CinJ Trudtj. Evolutlou ot By ft. P. EotliwelL Id VqI. IV.

of '-Thf Mineral TndiiPtTT." IWB

Btlliali Uolujubia. Aliuiiig Iaiws JSS

BrlltsJi CchhiTiihia, Unlti States and WaBMngtan MiofngLawa .80

Coal and Metiil Mluur'a Pocket Brok.,. S.T5

4\ml Mining. By H. W. >lu-tn-'S , 6.0(1

Col , ttv George IJ. Anlre, 16. W

CimlanJ Hoa] Miolut: By W. W. Smyth , 1.60

CoHieryMniitiser'iCEiiculiiUjr. By W. FaJrley., ,..., ,. l.BO

Ck)il[ery Mjiua"r'b HodiDkhiIc. ByC fiunely ,, 8.7?

CoUlpry Wt>rtiae iUid MuflaetO' By H. F. BulmaD atidR A. S.

Rxlinayr" ,. 600

Corivni,iilijri (M MLiit-.H, EtH***eftfi Fi*Uwr and SoR. By Wffi. HoptOH'.,. I.B6

Enjthv n-Titl CittuT HiiK'mlsaiid RliQing. By IJ. C- Da vies B.00

Eci;'.':itiiitr Mining. U 0- W. TjCtcic , B.OO

IlydTmilit M luiiig. By A. J, Bowii' 5.00

Bydraiille HInlne'. By T. E. Van WageEan l.GO

Ltadr oud Zinc Mining iDdtiHtry of Mlssuud and Kansaa. J. O. Holt

bouirh d , , .50

HetaiUterous Mines. Hacliier-y. By K. H. Davtea S.OO

Mine Drainwsei, Pumps, EM. By liana itehr 1,M

Mine'fimberin? 1.00

Miuf? VtfiJiiilutliia, By E. B. Wilaoh.,., 1.85

UiDi'ral Industry, The. Its Btatlatica, TecbTioogy and Trade in the UijJced atatesiAndothiif countries from, the ettrUeBt tlCOrt. VoL 1

Btatirttii-stothend uf ISU* 2.50

VoLU, gtallstisticatcitheendof;i899. ...,,., ,...,..., b.qo

vol. m. " " " IBM 6.00

Tol.IV. " " IBM 5,00

Vol V. " " 18M IS.OU

ToL VI, " " 17..,.,,.. 5.00

Vol. Vr£. " " " 18B8 5,00

Mineral Lanita. By H. N.Copp... 4.00

:il, Mines and Mining. By H. S. Oabom 4.50

MtHere" Hnnrtliook. By Jolin Milne 3 00

MLnr'ii rooliet BoQb, Bv I!. W. Lock 5.00

Minor's P(H!kPt Bnn.k By F- D. PciwerB 3,S0

Illiui±ii and Mining Men of Coluruio £.50

MittiiifT, Rv- Ariifilf] I-upton BOD

Mlulnif ]£a\nvEritie, G. C GreenweU 'O.OO

MiTiiibj;: ILW!a ur Colon] inu ,.,,,.,..., 1,50

Mruln' Manual for i&. By W, R. Skitmr , , SOO

XlQlne- RlgliEii in rtt Wi?BU?.tii Htati-a i\nd Territories, By R. S. iHorrisoa. 3.00

Klied Metals <ir MKjilTk- .-Vllciyri. By A. H, TfloPUS. IlliMirrtted l.SO

Mcdra C*>kt' OvnR and By-Prt>ducts. By O. Lun. la Vol. V. of

"TIjo Wini'ifll InduBtry." , ,,,. 5,00

OreandStonp Minlnff. By C. LeNeynFoater 10,00

PhuKijluileij uJ Amtrica. Bv F. Wyacc ,. 4,0U

IVflctic'fil Nott-j? ou Hvdraiilii-' Mtnfne;. By Oeorge H. lrans 1,00

Pmctical Mining. By J. (1. Murply, .w , l.SO

ProapeotinK for Held and Silver. By G. iJke I.JO

ProH™ttora,£iplarerB and Miners, A Practical Guide (or. By C. W.

M uore 4.78

iTroBP'-w'H Field asud Ouide. ByB.ti. Oaboni I.d0

Qood Books Of Heferencb.

PtOBpector'sHoji'lbook. By J. W. ADdersoQ l.£0

Prospector '!4 Manual. By H. N. C'opp &0

Report Book for Mining Entfiueera. By A. G. CbarleLon 2.Dd

Blate and Slaty Quarrj'lug. By D. C. IMvies S.OO

Story of AiJiLTiian CoaSs. By Win. .1. NicoUa SLtO

Story of a Pleoe of Coal, By E. A. MarttB 40

SUiry of the TA.m'i oS Illustrated by tlie Great Comstock Lode "Bv O.

H. Slilnii IBO

TinMiiiiug. By A. G. Ch&rleton..,.,,,, .,,.,,„. , ,„ l.SS

TuaneJlDjK. By H. 9. Drinker , flB.OO

TuHHeJii>B. EyP. K, Clark, ,. ,.. , ,..,.,, 18,00

YeuLUatloD of Mines. ByJ.T. Beard ., E.&a

Miscellany.

Ci Ensineer"'3 Pocket Boot, By J. 0. Trautwlne .,.,, EOO

Field Bftok Tot Engineers. By Henck S.M

Hydraulii; FMmxilw- By T, W. Btene ,. S.IO

Byiraulfc and Water Supply Eiieiiiefirinjf. By J. T. Fannio B.OO

Hydrauliif. PracLical. By P. U. Kandati S.OO

HydraiiliL's, Pmctical. Bj- T. Box 2,03

MecbaukMtl Esffinoer'a Pocket Book. By Wm. Kent. b.00

Petroleum. By W. T. Bronnt 7.

PetroleuDi. By Ben J. Crew 7.50

PelToleain DfBtfllatioa aud Idodea of TesUnif HydrocarboDB. By A. N.

Leet S.W

Sdbveyikq.

Colliery SnrvTing;. By T. A. O'Unnohue BO

IjOgahtlim Tables, tiy Webslur Wrlila 60

Levari c)it II Jc Tabl. By Vtiii Vea 2.&t>

Mftthemiitiful Tablpfj By J. Pryde,... ...,. 1,75

MiuwSurveyfDja:. By U. H. Bronph ,,,„,... S.

Plan" Siirv(;yir]i;, By W. J, Bfiytnoni.. 3,00

Oiiantiity Hurveyin fcrEniueurs, etc By J. Ijeuilii,g 6.D0

gUfwey PruutU-i. By L B. Jaijkii „.., ,...,.,. BOO

SurveviTiR. Bv W. St. GHIIeftpio B,BO

Surveytng, A Fractloal TreatUt on, By H, S, Me'tritt ,.,.,, fi.DO

Survey inR and Levelling InfltniTTn-nC-s. By W, F. Stanley 8.00

SurveyfTig Inflcruments tor EuL;meers. By I. O. Baker... 8,00

BurveyioKi Mutiual iif. By F. Hodtuian. fl.&O

BurreyiTiE, practi-nl!. By G, W, DsIU. .,,,,..,,.,,...,.,,.., 8.00

SurveyiiiK. Thtiury and Pratitice of. By J. li. JijIidsod 4.00

Surveyors' Formiiln'i Tahls and Mernonui'JP, By J, T. Hurrt S.CO

Burveyor's (Jui-li.". By A, Litsnain.,. , ,. ,...,., 1.50

Suteyoit Hand Buok iar. By 74. Merrlmajii (uid J. p. BrooltB.. . 8.M

SutitfirrBtieous BuTtif iBg. By T. Ftiuwick aud T. B&kar

Plat& 1.

Fig. 1. — Idealized Btep faalts.

Fig. 2. — Actual fault in the Leadville diBtrlot, Colo.

Fig. 3. — Simple fissure without displacement.

Fig. 4. — Idealized fault, hanging wall depressed.

Fig. 5. — Idealized fault, reversed, foot wall de- pressed.

Figff. 6, 7. — Actual condition of examples 4 and 6, showing bent edges of the strata.

Fig. 8. — Contact vein, due to movement of strata.

Plate 3.

Figs. 1, 2. 3. — Illustrationa of trough faults. Fig. 4. — Different formB of fisaures, shown horizon- tally. Fig. 6. — Anticlinal axis {A) and synclinal axis (£).

Plate 4.

Fig. 1. — Folding of rooks; horizontal plan (after

Geikie). Figs. % 3. — Cross section of the same rooks (aftor

Geikie). Fig. 4. — Value of rock exposures to the prospector;

Bhoving utility of surface croppings, as

compared with underground workings. Fig. 5. — Trough faults in coal seam (after Jukes). Fig. 6.— Extreme folding of strata by lateral pressure

Plate 5.

Figs. 1, % S, 4. — Lavas injected into the bedding

of rooks (after Geikie). Fig. 5. — Granite intruded into metamorphio soliists. Fig. 6. — Basalt intruded into ooal seam.

Plate 6.

Fig. 1. — OompresBion TeiuB in slates or shales (Key- atone mine, Amador County, Gal.).

Fig. 2. — Vein in granite, with spurs.

Fig. 3. — Vein on contact of porphyry dike; one waU "frozen."

Fig. 4. — Vein on contact of porphyry dike, through limestone.

Fig. 6. — Exaggerated representation of "pocket mines" in granite.

Fig. 6.— Refilling of a lode.

Fig. 7, — Fissure veins, with associated beds, at Tombstone, Ariz.

Fig. 8. — Mineral deposit following joints in lime- stone.

Fig. 1.— '

Fig, 2.—

Fig. 3.—.

Fig. 4.—

Fig. 5.—'

Fig. 6.— I

Fig. 1. Fig. 8.

Cross aeotion of the Wheal Dolcoutb, Corn- wall (after O. Le Neve Foster).

Hematite deposit, UlTerstone, England (after G. Le Neve Foster).

Zino (oalamine) deposit, Altetiberg, Ger- many (after O. Le Neve FoElter)..

Wlieal Mary Ann, Oornwail (after 0. Xie Neve Foster).

Great Flat lode (England), segregated deposit (after C. Le Neve Foster).

Cross section of Mother lode in Maripoaa County. Cal.

Bedded porphyry and quartz veinB.

'YeiQB of satin ap&r ia ooDgiomerateB, Death Valley, Cal.

'YeinB of quartz in conglomerates. Death

Valley, Cal. 11,— Bedded veina, oroppiag aroiindhilL

Plate 8.

liongitudinal seotion of Wheal Dolcoath tin mine* Cornwall (after C. Le Neve Foater).

I I J I I I I J J I I I I I I r I I

Plate 9.

Fig. 1. — Dip of veins.

Figs. 2, 4. — Looating working shafts on a lodo.

Figs. 3, 5. — Illustrating course of an outcrop in a hilly country.

Fig. 6. — Bavine formed on lode, when the ore con- sists of soft material.

Fig. 7. — Bake of ore shoots, and formation of ravines across a lode of hard quartz.

D

/

'

'

'

' /'

RgS.

Plate 10.

Figs. 1, 2, 3. — Formation of the ancient buried

gold-bearing river deposits in California. Fig. 4. — Probable length of tunnel to tap the

"channel." Fig. 5. — Side ravine or so-called "overflow" of

gold-bearing gravel. Fig. 6. — Basalt cone (6), through gravel bed (a),

at Laporte, Cal.

Plate 12.

Figs. 1, 2. — Folding of gravel beds at Taooma,

"Wash. Fig. 3. — Section of river bed,. Bhowing effect of

the bed rook on the retention of gold. Fig. 4.— Slate quarry, showing stratification lines,

B, B, and cleavage lines, L, L. Fig. 6. — Contact vein. Garibaldi mine, Cal. Fig. 6. — Unconformable gravel beds, divided by abed

of sinter. Fig. 7. — Changes of currents of water in a gravel

deposit, with petrified trees, Sailor Flat

mine, Cal. Fig. 8. — Folding of slates by pressure of dike {D). Fig. 9. — Cafion or ravine, following fault. Death Valley. Cal.

r,g.-5.

Bse/ of Finer.

flg.4.

Flg.5.

Plate 13.

Irigs. 1, 2, 3, 4, 5, 6, 7.— -Data for estxmatine quan- tity of or£ in a mine. Fig. 8. — Miner's horn spoon. Fig. 9. — DeTelopment of mines. Figs. 10, 11, 12, 13.~Strike and dip of outcrop. Fig. 14. — Mioa crystal. Fig. 16. — Hornblende orj'staL Fig. 16. — Augite orystaL

Plate 14.

Figs. 1, 2, 8, 4, 5, 6, 7. — Showing method of mak- ing loofttions, good and bad.

Fig. 8. — Artesian well in basin with continuous rim higher than pipe outlet; c, d, olay beds; g and e, gravel beds; a, snrfaoe dirt; w, well.

Fig. 9. — Artesian well in basin with rim defeotive on one side; but which flows because the basin is sealed by the water-tight clay bed c; g, gravel bed; a and h, olay seams; w, well.

Plate 16.

FigB. 1, 2. — Oorreot form of blaze on trees as witness

marks. Fig. 1, front view; fig. 2, side

view. Figs. 3, 4.— Good (3) and bad (4) stonfrnd-6take

monuments. Fig. 6. — Posting location notice in tin can. Figs. 6-12. — Making locations (see Chap. X.), Figs. 13, 14. — Blind lodes; longitudinal and cross

sections.

zn

Index.

A

AbyBsinla. EwJdon In

A'luni!i,atJae,,,,,,, 807

AifTlQultum] tighta 172

Aluluutor . , 4g

AlRt&n Moop tniue, id

Alt&bere mlneil 113

Amador mloofl JOS

AmorphOQB. , ,. 207

Aaleslta ..., ,, ,...,. 819

Authnwlte 2BS

Anticlinefi l-jo

Antjmcntril sMver ., 210

AatiniQUJdidH and a,t\9etildea 18B

Anilmrmy flEd country rocka..,. JS8

AntitiiijiDy ores .,,... ffliJ

AiJdcit.. : so

Aqut'OUB thaory. .,,,,, ., imj

Arastra. „,..,.., „,,,.. aS

AFUjDiVaceDt SOT

Area Vein m-orlced , , 38

AJ'Kf'niite, ,,,, , aio

Arftjoic 23a

Arniiial pyrite..,.,.,.,. 221

Aj"Btiii!t aad antUnanldes,,,,,,, laz

Att!4Jaii wella , 310,315

AE-b-'B-CtJ. ,H , , ,,11. 3U

AalKiKtoH [n honibleiide j-ocks 164

AflphAJcuui , . , Sal

ABtsaylag ,., ,,,,, U4

Ansessmeut Work ,,,., ITl

Atufumjte !fia

Atcunic weight, J 813

ACLLd , jaig

AlJglto ..„, B9

AutuDJCe SS8

Axurlbe , , ,.,,. ajj

B

Boclu .,., , !J4

hold MjLluiaJn .,,,,,,.. 1*1

Hara. Hi;?er ggn

BaTT/t'-& , Hai

Itoswlt 51, &i„ S8

Basalt. TFOBppctiDgla

Batopilas, .„.,... fl. lui, 103

Bauxite 83U

Eecker, Q. F., on SMaiBlioat

SpriiiKB 107

Bwkilna planes . . . 41

BedaUlpof ,... no

Beds, OrB..,,.,.i.,. — ,,„ fU

Beds, fnitcropa crf 1*7

Beds, Tliickntstja of m

Beds, Workable 71

lieuiiigo [uiDsa J83

KibJiograpliy., „,.. gg

biauiuUi, NdtiTe,..,.,... 2SS

iti.'JiTiiutb iori?s

BsCuDimouB cooJ seg

B!a.i!lt silver , gji

BJeade gi8

BIbdiIb and ealfiQa, Senaratiae. SB

Blind lodea ,,,,,77!,.. 7T

BoKiranoreL 8, 14ft

Book! uf reftirtiODe ,.,t,. S38

BoraLB ol litLe iffii

Bopft ... ,.14a.8SI

Borebole records ai5

Bore'htHle, SpereBberif. ..,...,,,,. Ml

Borinfa fur cuak... ,.,, lo

BoTliifii ill gravel 10

Borinpi, Useleau.*,..,..,... s

Bomltje.,., ...L.ii.i.i.., tl8

Biitrj'oldjftl,,,. ,,,, jr)7

Uottuia gravel ,,,„ fl

Bowlder el&y .,

lirocela ,. ea

Ereece & Wheeler mlnQ 3TT

Brick cUiya nia

UrUllftEt 30?

Britlle .,„ na

Srittle8i]Fr ail

Broqildo of silver , llt 811

BuliratoueB ,. gj

Bulkof oppH 18

BurH:!liH.nllta 213

0. 4C. shaft 109

Oadmium 227

Ca)ani (re , , gi7

CalavDi'ite , ajg,

Oallco district,..., iqb

L'annpl coa! jjog

L'aOon Citiek ,,,. iqb

Cni'bo-Dflie of (."opper .4

Ctirbt'iiiiti' of leiicf,,. SIS

Cnrlwnate orpine, , S17

CarnaeQ isUuidsalC. 141

CarpentBr F, B., oq Dakota gold

miDea

CaeciuUt ran.,,,, 1£S

Indsx,

Cafipiau fiea salt 141

Camg 13

aieaato , iMT

Oerargyrlte

Cerucsite 216

(jluUcoclta .,... aia, nfl

C'haJcopvrite. 232

46

t'hareieB lor locatlonft. ... . 191

Cb'-iiiirb salt 141

I'liile Kaltpter. 2M

Cliloride of<pperi... 215

fiiJoride oi'flUver 116, an

Cli l&ri to H ,., ,

Clilorlte si!hl8tB. , fifi

Cbroiae and country rocks... IBfl

Ohrome in schists lOB

Chrome oCuufrenotfl J33

Chrome ora. - &S3

CJiPQitiite 8aB

Chryaocolla SIS

Chri'flollta ..,, 3fi

hutes 91, aw

Cinnabar. 11, 81S

ClalLUH {Swi altw LocatLona).

Clalii>B. LocatJog .107

ClyaiialyRe , B43

Clay, Bowlder , QT

Clay, Brtek , £43

CJfty.Fire ..,., &4

C]ay Roufe '"A

Clay. BHm 14

ClayH GS

Cleat .,,..,,., 363,

deavoKS 40, 330

Coal ,.,, , S59

Coal beds, Faulted Q

CooJ, CoEumdi'cia] value. 2GD

Coal, Comrwsition ot 2B0

Coal, IiiipundtiB in 36H

Coaliuines, Creijliii IC

CqbX prospL>ctiiig...F S0S

Cobalt, bloomi 34&

CobAk it! bOtan. , „ 107

Cobalt-uioJtel,. 138

CobAitores... i£25

OobBJtJte., 235

ColraWStS.. , .,.,.. 26B

Colombia, Sulphur fu S48

Compact.. ,,. aOT

Campafifl les

CompetltloQ M

CoavptwiiiOii veiDS US, ItK

ConiBtock lodo. . . .18, SO, 78. 92, flS, 101 107,109,111, tl3, 118

CoucentratlOD 30

OaDiilioldal 207

Concretlonarr . . . 807

OonElomtrau!. Volcaale M

Conglomeraleah...

Contjict veins Bl

Coiitacta limfstoae U

CoQte&ta, LocatioQ 195

Copptirandcoiiintpy i-ocka.. liW

Copiwr i:li]oridtf ais

Copper In bods 144

Coppur uiiutH, Lake ' lOD

CopptT, NqcLvis ..,., 91S

Copper ociuri'eucus IBl

Copper or©i I' ST

Copper ores tUt

Copper oxldei. 214

Copper-sJlvur... 100, ISS

Coppa* BulpliHte. , SlS

Copper eurfiMf orea. lUU

OorailinH limeatoDe 4>9

Comisb miaeH. ..t03 IM llO, 11:3

Corundum

Country focll (icd grtogue IH

Country rock Kamplea.. 1G5

CfJUntry rovkaand vuiu fllJIng 180

Country rocks, Effect oa flKBures. ffl

Cracow aalt 141

Creeping i a

CroppiEBB. ,.., ra

Croas-cuttlcg' AB

Cross-cut tunnels 197

Oryoiite W&

Ctyat*!. a4d

OryatallizatiDn of ndueraU 380

Cuttanite.. ,,, £13

Curtis, J. S,, on old and silver In

icba lO?

Cuprite SIS

Dacte fifi

Daiutree on KoLd ocGurrvDces 107

Pana on metuls tb Kbbe aod

graslte 107

Dana on nickel in lava-, ,.., 107

DaubrSe oTi muteoroidB IDS

Death Vrtlley B&, 1CH

Decamposjttoa of ore at surface.. IBO

DeePEraveJa BJS

Deposits, vaporaUid 14S

Deposits, rpnufjf Hi

bepositain limestoDC! ICB,

Dtpoaitft, MiUWRl wdiuieut US

Deposits oliver thau velQH I3&

Dfepoaite, FhyelCfiJ diarauter of . . . 08

Depths RicLD(?flain ISO

Derbyshire mines 196

rJevRlopniRnt 4, 197, 913

Diatomaceous earth. .,.,.,,.. ..4 10

IHkM ...72,76, B9

DikM, Lodieaon U, 154

Dlorite, Gold in 107

Dip 70,78, 148

Dtscbaree of water 304

Dolcosth mine. 18

Dolomite 47

Dredging: jMN

Drift mining.. , 901

Drift tuanBla ,..., SIO

Drifts 9(M

lynsx.

Diytawa, , , SIT

Btwaahliig.. S??

Duiile SOT

e

Blectro-chemlcaJ action LIT

BlmeDtA... — 816

Eleralor, Hydi-auiiC SW

EtT4nit Cjl

EmboUte,..,,.. , ail

Emerv .- 235

End IfiM..., 1S3

Epwtasalt 14B

E,roBl{)Q of veltift 169

Kf yi liFiWt 4 S2G

Evapomtioa 180

F

Fauita.. ,. F3

FAUlta In KraTfilfi, ...,..,... SW

Pftalta Rerrse. 86

Piu)lB(,6ime.. ..,.!.,.., m

Faulta, Trough; VT

Feet of minerals SSO

Feldspar 37

Ftalwte &S

Fit>roua SOT

FDifonn, ,. ..,.

FlUoKof TeloB , 09

Firachy ,.,6S. Sl

" Biaaupe TetnB, True" tt9

FJsaurw.,... S3

Flaftonfl. : £1

FlamlD); cool 8d4

FUat , 4fl

rioftt .,.., IBS

Floor &i

Fluorapar , , , , , , . aST

FoliLtMi eravBlB SW

Folia(>id , S(iT

Foot wall tuunelB -. l&Q

Foirhbammer on metiUB In ea.

wttler loa

Forniatiims, SiippeBfiloaof 188

FurtiLKul! iriiQerals 3S1

Fnve""''" rocks. (iC

Fraukljiilte £]S

Fraaer fefl

FiveetD[i r. , 61

FHtfllbbeciltQ. SIJ

FrDztieiOB. 80

Fiiliiflnoun caj t..i-..i.i...i. 9S4

ifptmcecreek. IM

Fuubilitf of minr&]9..'<. 3SS

G

GalecB aiB

Galena and blende, BeporatlaR. . . S6

Galena id UmeBtouc 1C&, 16-1

Oangue.,., ,,.,,.,..,.. , 80

Oaueue and c DUD tr; rock 133

OaritaldlmSDe. T

Qiuimta 88

Ooa coo].. fM

Obb, Natural , £GB

Gann veins. ..86, 4B

tiefkk> oa Bait in Caspian... Ul

Qeatblte

Oeodes lOS

Qeoldc Bcriea. ,,,,.,..,,. .9Ti SSS, (JeoLoKlcal Survey, U.6 ..,.,..

Qeoreia miOes

QersaorfflLe ,, ,,.,

Cladal dpO-fU

GloclAlpiiwluctfl..

[:iju:j>r mlae. 114

Oodss H

Gneiss and iraiiltj, Opw In 10?

Gob 9CG

GoliI Btifl cc-uatry rockfl- — isa

Ofild AiLd Biivcrlu rocks 107

Golil, CrjHtatlized. 101

Guild gravel deposits ET1

Gi>]d graYelB, Faulta Id HB

OtM eravele, Folda In

Gold Id beds 144

Gnlrtin dlorite. IW

Gold In ma water lOB

GiM in sK-rptinline 10}

iQnli! in ftutii Dakota 131

old. Natiye. ,..,SOP, S69

Ooll DCi_-UETei;<!ieH., , 131

Golci ore. AwayiQg ,,--0#, 86

Gold Ore, Homing,., .,,..85, 2fl

Oold ore, Tefitlng S5

Gold pat ..-,4 388

Gt:ild, Ti?tS ror EM

Gold tellurides SOB

Gi>ld VEdDg. ErosiQn of 159

GDUce 79

Grade of gra.vel deposits... £T&

Grade of ore 21

Grand: CaQou... lEKl

Granite ST, S2

Grauite, |£old Id... 1(9

Granite, Veins la GT

Gramilor £07

Oraplilw

firiLvcl dfpoBita,,.,. Sti

Gravel dejHXiltjfi, Origin of Sm

OfflT©! tiiuifss, Cl*y In ,,.,., 14

Gr&vel mlDoa, CreeplDgln., IB

ChTO'l uilQlEg , SflO

OraTcl, FauitBin.. HI

Gravel, Fcildftlti ..t. VS

Gravel, TeHtln SK

Grav conp&r SlS

GTfS.t Flat 1<m1b 113

Gypsum 148.148. flStt

Gypaum in solution 141

H

ElATrinrBi Geological IM

HiuigiiJiwaJl tuuDttia 1D0

Index

HeadCentor mine 100

Head of water S04

HeadlOK 804

Heat, Cndereromid 109

Hematite S19

Hillside depofllta 233

Horn silvffl- 100, lOfi, Sll

Horn ipooii ,,,,.,,,.,...,. SC. lOB

'DclP, ,,, , m

HornbiiudB radts. Asbeatos In 164

Horses , ,..„ T8, 91

Hydraulic elevator 2fiT

Ejaraulio mmiDgf. 689

iCTieoua tbeoTy &9

IliluDls mines 115

nmenlte,. in

Inch, ldi[wr*B j BOS. 3DB

InipUBe-.,,.. aw

lafusoriBleBjCh IS, 40

Iride-ent..,,, £07

IridosailuB. , SIS

Ironcat-b}Date ,..i.>i.i.ii. 2S0

irQn-manfaDeee IS3

IroD ore DedH 148

IfoQ or*, fine -8. 143

Iron ores 219

iron aulphjile 220

lubel mine 105

JolDtft, Strike 41

Jukea on trough faulta. 67

K

Kaolin

Eamboghaz 8&1C, 141

liyaCanBmlne 9S, 112

EiAas , ,... 103

[Ake Superior Tnlaa 144

Lal£e, Saline Ed

Lamiaatioa , 41

Land piicaa 1S&

Lands, AKrlcull:[iral 172

LandH, Timber IK

iJiplUf 68

laterals

Lara , {SO, 51

Lavacuip. I. 9T8

Lava,Nelin, ..„,,. IDT

Lead ,. K!

Lead and coijutry rooke 1£S

Ladand ftiler,,, 3S2

Lead carbonate 31G

I*ad 111 Ii(?i-byiihii.T. las

Lead in llDiiBtoiic 115, 11114

Lead. Native. 215

Lead occiiireucea

Lead ore ...4, lOl

Ieadore Is twdB. 1'14

Leculoxidi.,,, 16

Lead Bui)jluite 21fi

Lead-zinc t8S

LeadTOle 9,, 99, 14&

Ledge 7$

Leeds mine ., lOB, 144

Lerelfl fiCH

LlbtJindmin&ralH. HO

Lune Bulptiate S89

Lii]i9U)]ic.,..,H, 4B, Ml

Lluiestose, Caves in.. 146

Llmesione contacts..., 44

Lime&loce, L'oralUne. . 44

LicPffStoiie. Deposit* In.,. 103. 1)G, ilW

LimeBUme, ProBpeetiDg in KM

LicioHfte Elfl

LitiKaOoa , J4

Ll7irflldj(eon ioid Id Babwa.ter.. 107

Locating regulations IGA

Location cbargfi ,...,... IBl

LicatloD end liueH IS

Location, fHnal proof of IM

Locatiuu lentjith 1S8

Location noticee ITS, 170

Location, liblleaUoii of 198

Location r]nirenienta Iflg

Locations, Describing iGD

Looatiou, How made. ,.,... -.170, 177

LocatiooH. Imperfect 168

Locations, Lode. ITl, 177, ISfi

LootiQDs. Making... ,, 167

Locations, Placer ,...,.,,, 170

LooaUmiis, Procwiure iu 191

Location., Puzzling , ,,,,., IBB

LodB ,,.,, 73

Lode IcnjTth ISB

Lode lini! ,,.. 179

Lode locations... 171, 177, IflB

Lode locations, ftoceduFQ in 18S

Lodes, BUnd T7

LAdsoniUilces M

Loatvein.- ft

M

IHacliJne waablng, 8K

UaKnoBite 47, S4S

Mouit. .„ IQB

magnetite 219

MttJacblte..,, 814

HaUeablfl... 207

X a tn ni J l lr y. , ,,... 9D9

Mammoth cavB Ilfi, 14B

M&uitt.tieer' and country ]od4,.,. 139

Manganese in CK-flan 107

Manajn egg .Iron , IBS

EilEui);aoi occurrencsB IBS

UanianeBe orvfl ,...,..., SSI

Marblf 47

MiLricusite... SS9

Marks, Btakc ., ITfl

Markfi. Tree ITS

Masses , , , 81

Massive SOft

Natrtx.,... , m

UaiT Anumii HO, ItS-

Index.

Melooonite ,..,., SU

liWrcury (See QulckaClTer).

Mf>[ju;iiina.baiitB S]2

Ml-UUIc JuHter BtH

MtalluTyica] experimeotB 3.

Bf et&UuTtcitl plaut, FJauulu S9

Metalsaml rockB, ,...,.. 1B0

HataU aaaocjau with eacfa other 13S

HetaU, DlBiributlon of 106

ItfetolBtSp. of IT, IS

Metate. vaiueaf. , aai

MeUwrolilH l(ft

Metamorptilc rocliB.F.r. 04

Metojuorpbiam 4S

Uetiic Hyatem ,, SS.'t

Mlc*..,,.,. 38, Sifl

UicAceoUB Slid

MiUcapacitj... 3B, 33

Mlllfitoues fll

Mjue coBt nnd output 10

MiDti. Dellultioiiof.. 84

Mine fojlurtw, CauEeaof 14

IWiDC water ...1D7, 201

Atliif, What cooatituteaa 13

Mhi>?rala. ObaraoterB of

MinemlM, ClnJUtiflGncloD af SIH

JKIniernlB Cleavopw o(.. .,, , 380

Mluaredti, CrysCuIllxalloD of 330

HibjruHs dibXingulBhad accordiiig to f t-el , 330

lo odor sad

MiiralB ftiBtlngutehecl &c>cxirdio£ totuste sua

MinemlB, Es&TB&L fonnsof 93J

Minerala, Frncturoof.. 331

MDBrals, FusibQity uf 51H

MliuerttJs, KardBUBS of SOU

MJnornl '"Id plaice" 172

Mlut-ralfl, Insoluble :B

Mineral, Qualities DepeadtD? od

Ugbtof 390

Mluprsls, Ewk-forniinE. 38

MJuertUs, uparatlog... 2S

MInfralK. 9o1l!>i!e. .,,,,.., 860

Minerals, itnictTLire of 331

BCInerals. Uaeftil ,,.„ S3

UibentH, Yaiue of SSI

Hloeralfl, WortbleBQ...,,,,,, , U

Mimer'tiinch 8(H, 3u9

Mioefl, Devlapiuent. uf i, XWH, 303

A!IlDu.tB, UrjFUfCfBSfuL. 10

UiD(?, WorklQfi; facilities 17

SHuIagcniidltlims 19

MlEinir Diift Ml

Mtninj failiirea. 3, 14

Mining ground, Patents to IflT

Hlnine. Hj-draiilic 289

MiDln, MitstakeB la 1

iHlnlDjf, Placer 396

MiapJckeL Kl, SS5

UoIybdeDimi.. ..,,. .- £27

HoDn lake 14S

ModteCristo diBtrict 76, llS, 114

Morunii'Hts 173, 174, 181

Alodlier Icdo. ...76, 104, IIB,

N

?Ja(ryflff rallies , 6

SoKyBitB 210

Katurolgaa. Sas

KlLToMte... K4

Iickel and country rocks. ISS

Niokel-cobalt 133

Nickel la lara 107

Ktckel Id ocean. 107

Nickel ocher ,

Nlokelore 2&i

Ntckol silicate..., 3S4

>fiter 8M

NiUT.ChUe SK5

Niter (See Saltpeter).

Ni'lice or]oCfi.tionB STB

NotJt, Postiag 17fi

Novs. giotfa aohlstfi. ISt

O

Obeidlan BB

Ocotllla ICS

Odor of Minerals , 880

Opals ill basak Ifl4

OllTine. 89

OnioD VeJlev dike,.. OO

Oijllilc ao9

Opaque h.,, ,...,.,.. r,.,, 990ft

Ori:* <--ha.Tit'B B.t water tavel 1Q9

Ore, Iit'flpition of,.. i. aw

pre depicLuiaDd country rockH... IK

Ore depoftitft, Form Of

Ore DiHtiibutloi] of 12

Ore, Oi'(i.dt!<if.,. , 21

Ore in depth.. ISa

Ore ju liMestone iCfi, 115, 164

Opb "in Bighl"-. 21

Ore, Oi'ijrln ot... 100

Ore, Pockety

Or.BaiDDllnK' S9

Ore, Siiliitifia of lOfli

Ore.SourMof, .,,., Ill

OreHuppI}' needed SI

OredeptiSitH. PliyaiColcSw, of... 09

Ore thfcknBHa IB3

Or* tollnge,,...,.,,,,,.. 32

Ores and rockH 130

Or¥*i, Bulkcf , 18

OrPB from bpji lift

Oi'es, Separating 58

Ores, Sp. RT. Of ir, la

Ors, Value of

Orea, Welghtof 1ft

Orptment.. SK

Otago mLcieH ISB

Outcrijp

Outrupaud springs ...t,, 368

OuU;n)piLUd vegetatloQ.,. IQS

OutCl-qjpin locfttJOfl. .., ..,.-.

Outcrop, Iespa of tbe.. f,'.,,,>7, ISB

f

Index.

OiitCrop of tbEhb. T4

Ouiurtii>. Circular 73

ruiicmp, Kusty Ml

Outcivi of btd.i., 147

Outflt. Prtispecting IfiS

"0VyrilOiV6t"GmVf)l SSI

OxiiloHof iroQ. S19

Ozoterlte].. , S4i

P

Pan SS3

PiuibiDK IBU

Patents ,.. lf>r

Pfttenta Frocodiire ID iBl

PfltrolBuin £57

Fetzlte 310

Phosphatof uranliim... £23

Pict, ProHpecMDg Iflfl

Pipeclay 878

Ities, vvaterin 804

PiBOLitic ..KB

PitB., Profipect. S03

Placer louatloan 170

Ploceir mlDtniiir..

Piaster ofpariB SJW

Platinum .,,,. S1I

Plumbago aJ8

Pi.jd*tits... -..,..,- ft

PcMjkets, Fault

Pon.i'|niii clay,.,. sa

Porphyry .63, H, 68

FOHrliiK- notion ., 176

FotflKiinm nitrate SM

Pi.Utr'a Clay S*S

Pries and profits SO

FrlceauIni&CaJlfl,Qre&, mlaHirBJfi,tc. 31

Promoters 4

PrDtipei:tinj; . h . , . . . l&O

Pro8pti!tiiiif and Hprliis IK&

Pnjspectin Q.nct vcielatfon. IfiS

ProHpeoliiia anil wutersyfttem.,.. 163

Pi'E>tiptKUn Corcual. .,...

ProMpet-tliif,' tiutnt. 165

PnjspccHiJg— WliftC tolookfot ISl

Prospeflin—WhereT. 164

Praspect pitSd 909

ProLstite- 811

Pdilumelaae ,.,.., ,.,.. S32

PubUcatioD of locatLon ISS

Pumice U49

Pyrargyribe 210

PvrilH ao

lrite, AuriferouB ST

Pyrlic. DiMay o( 114, ViV

Pyi-oLusttc JSa

Pyrrhotlto 8W, SS4

o

Quarts ..., , 37, S43

QuartK-porphyry... 6&

Qttftnite. .,.,H,, 61

Qiilclcllm(>

Qiijdksllvrr miiJ etJUftty rocks 139

Qijifkaili"er itt ti-'jiiaboat Sprin£;.iOT Quicksilver lor teatiug,,, 16B

QiiickBilver, ST&Uw 812

Quickgilvup (HWUPPflQcea 133

R

Romssy on Batli salts 18B

Italicar

R>;d.Jotion worlcd, PlannJue J!0

HeductiDD worica, UnsuLtaJQle B

HeildtioiiH for locating 189

Reilntloua, licat 171

Biuifonn KB

Hc'sei-vca 4,fi, 34

iiesljious am

Rhyoiite SB

RiblKi&ri.'ct..,,,,.,..., 3B

Kit>l>c)n structure , ,. 1\Q

Rio Wirgfu sale 141

Riper biire .-.,,.,., ..,.,, BBS

deposits ,,..,,,., 071

Roada , ,,,. SB

RocIe and gaague ISB

HockiiBiiaes IfiS

Hixi. Nusptes lEfi

RoclcB 86

Rocks and inttbiLB ISO

RVb, OhcTii . precipitated . 44

Rocks, CluAxmiiatioa of. ...43,334, SSB

Roc)ca. CtJLuposltiunof 68

RockH, Couiuounci..., 49

Boclffl, Cr>-s.talliiiB -,.., BO

Rocks, I-ecton RssunsB 90

Rwlis, Enjptivy ..,,,.,..,.,,..,, ISB

Rocks. KnugmentaL... flO

R£ioit<, Iii|]iiiiiiw an vein llidg. . . 120 Rocks, MtiUuiiorpliIc ,.,,.,,,.,,,, U

Roeka, OfKAu ' M

ftock?, OrijfiD erf ...,.., ,,,. M

RoctB, BlUcioiM Itl

Rocks., Simple .,

Rfy;lcB, Btratlfiad W

Rocks Volcanic N

Roof , m

Ruby Baflltt IH

Ruby silver , aiO. Zll

RutUe 8S7

SaU 141, Sas

Bflltat SpereabBTg ,,...,.., ]4t

Salt Arizona Ul

Bait In Caspian. 141

Salt in Qheire Iti

Salt in Poluid 141

tialt in Hotutiun.i. 141

Saltpt'ter, Chile SfiS

Salipeter proapBcting/. .,„ ]M

Salts., Soluble. ProapeCtiugfor... 104

Sample-' itinCry n>dk , 15S

Sampliag-, „„.,.., ,..,..,.,, 94 S&aoberKer od metikLH iik rocki,. ., 107

So-udstotii. , .,,.,,,.,,,, 81

SatJuapar 101, £1

Index,

Sa-FAfntnine. , 119

ScIiteW 55

8Mk tetich (i>i|:Kknit4... SB4

Stu-foruied oiia... ,., Mti

3e wjiu-i', MecatB In. 106

l?kHJj[TU'Dt nilaeiraL dupoaita 149

Ht-iiivirLi.L| GH&ica, , B5

tk-leniu? 4B, 839

Svaf?e .,.., 79

Btimi-RDthmclte MS

tenJ bitumiDouB.. ..., 9S3

HerpeDtLne 49

8(>TpeatiD&, Oold is ..,.,,... W

Sb&ftH..., S, BOU, Sul

, Useless., c. ,..,..,... S

Sbales , „ 63

Rhootfl, Ore 91, S04

eirterilfl 330

Sierra Neriula Tnlne,, ,...,,,, ]U1

BllleaiB ut uiobei 234

Silicate of zino 217

and L-uiintry rixrkii ISS, 134

Silver and ild ia rocka 107

Silver at Leeds 105, 1-H

Bilvfr, Brittle 211

Silver bromide 110. ?]1

Silver chloride,. llfi, 311

Silver-copper. 100. 133

ailTBr glance. 210

Silrcrla sea water 106

SSlver In. South Dakota, 131

S£]Tr-]ead 132

SUwr, KaOve Ml, SiO

Silver occun-eocM, ., , 131

gInUlDf SUO

Sintei' , 46

BlEite 43, 4S, 03

Slate Creek ,.,.. ,, 158

BliclcpiiEidea 79

amaltlte 226

Smeltiiig. 29

SmltlifiODtte. IT

Soapetone SJ9

fkidlum carbotinte.

SolfBtariti agtipn... HI

Sojulions, MJDttral 1D9, ISA, 1H

Stiulh AfriiJiiti jnlCCB ,,„ 1+4

Soutli I>al{oLa mines 134

Bpilflc graplty . . .,, 17, 18

Sperpuberg boring 141

Spoctn £&

SpriagE and outcrops 15S

Spurs 78, tH

Suikwt ITS

Sralactitic. 258

Stfltap. UuEy ol! 33

rail] capacity. 33

8tJiDnite. S3S

St£[init>oat Springs IQT

at(.'[ifai,]KH 8&

gt£phanlta, 211

Stibdite ttSl

atockworkg ,,.,,. 99, 108

Stoniwoll jackHOD mloa 96, 135

Stiifilng ,.,.. 904

SirBtirlcatloD 40, 60

t*ttH?ak picte ,,..,... IBB

BtreauitiD , SES

gtrite , ..,70, 74

StrikefaulCe BO

Strike lohiU 41

Strontia

SlTuctureotiDiiieralfl

Siulbt... a06

SulKnuphpLdBl,... Z58

SubmetaUie 388

Suipbiite" of Copper, , ,.- 215

Buiphatj orlead. SlfS

Sulphate of soda... ,,., S&A

Bulphide of iron SSD

Su]pliJd*i>f latTCUrr 813

Sulphide of iin <S3

Sulphide of 818

Sulpliur 847

Sulphur Banks 04:8

SulphuretB, PaanlB. IM

jgulphur&te,, Separausg SG, 166

Simip 806

Surface onis. .IW, IBO, IHl

Survey, Order f or i..

Surveyor. Authority of IBB

Surveyor, Dudes of. JB

Slirvpynra 188

Bui-vey<r3, ljiBtructiDtiah>i...]W. 196

Bucro i:uunl Ill

SutterCrcek mines..., 10S

%(Tilte ..64, 68

Sy I viiiiiw - 810

(jyncUnea 140

Tablen: SlU

Elementa.. 8lB

Utiologic Berles 67,323. 333

Mf;tal(<, Ores, MlneralB, etc.,

Value of 391

Metric System , S35

>fineralR. Cbaritctera of SSO

MlU'Srals, ClHsslRc&t.Joii (if S18

Mipprals, uTeavei* of 40, as)

Minral, t'rystallizati/iti of S30

linetals disringuiiflbed aGcoE<d-

lagtorBpl 330

Mineralfi dMlnguishad bccord-

itigtoorlor 830

Minerals distinguished accord

lug to taste. SSO

Minerals, External forma of 8S1

MtueralM, Fracture of 831

HineralB. Fmlhllity of SB

MinFrals. Hardoeos of 830

MJn>?rali<, Quabilefl depending

on light cif,.,.. ..,.,. ,.,...,... SSa

Minerals, ftructure of 31

Rocks, CIfcs9iflfttion of. .48, 8S4, SM Talc,.,.. £41)

d

Index.

Taliu, ,, , ,,,„,., 77

Tape 105

Taste of miDoitB B30

TeHuuidm lOG, SOO

Teat*, rtilitf of , 2fl

ITflsliB, Warklngr £T

TetraiiodritB.. 218

Theory, Aqueous 106

Theory, Ijeous.L 39

ThJckoesK of vein and ore 153

Throw.,. , , 84, eb

?iinber rightfl. 173

Time. Geologic...,,..., ,.,. 68

Tinajid couDtcy rocks..

Tin occmrences 131

Tin ore.. 11, 3ffl

TiJisuipbWe , 283

Titanic Iroo SSI

TirantuiQ , , SSJ?'

Tombstoue 119, 157

ToiiDAJir'arsa, 17

Tonuogu, CalCUlatiotL Of SI, SS

Topography..,, , IGS

Torbemlte aSS

TourmallDe ,. S&

Trachyte .BB, 63

Tranaliicent., 2B8

Trausparent 2&B

TiVDepTt&t''ii of mluera] bj wateir 100

Trap. 57

Trans 2&3

'" True flsBure Teina '''' S9

Tufa. 66

Tuoten ,, asrr

TUDDelcaanecdaDB 109

Tuftueia, CrossJut. 19V

Tunnels. l>rift..., .., SW)

TtjiiUKljj ik footOF habffiof'walL.. JM Tynilall miae 78

u

UlexIU a&i

tUverstoDe depoaJta 11&

Uranium 2S&

Tiiatlon of mlo.. ,.,. @0

TaHues of metalH, ores, mlusralB,

etc... 331

VfUMidium 238

VoRBlatioD a rude ia prospectius

Van, AeeaeitPactea 33

Vein, Diatance traceable 151

VelD tilling M

Vein matt<=ir 80

Vein structuire S

VeiM, Blind.. 77

'Veiua, CompresBian.. y&, 103

Veina, Contact fll

YelbB, DeSflittoii ot 72

VeiDB. FroMjn BO

Velneln gi-fttiite S7

Vcina, Meaaurinj \SA

Vein NjU-r&w 6

VelcBnotuniforni 19

VeiisB. on dilia H, 151

Veinfi, Opening 1S7

Vehja, QrigJo oE BB, OS

Vieins, Pockety ,...,,...,, 110

Teina, Rlchneaa la depth 1B9

VeuiB, ThJckneae. of OS,

Veioji, "True flsBuro" 73, M

Yieiocity of water dJachaise &05

Tftaiivinn iRTft. 107

Vitreous coppffi , sis

Titrtiis silver. SlD

VoIciicprtKlucUi. 68

w

Wad... „.„.,...,

Walls, False IM

WftllB, Vein TO

Waibiugtoti mloea U[, llS, 114

, Eylk of... BOB

Wattr diacliar 90i

Water in rnineft ...167. 301

Water lescl IfiB

WaLr iiiHasureiueat. 608

Water. Min& 108

WnMr piiwer Hh

Water pr(;sBure 3(

Waf-rfiyatemandproflpectills... \VA

Water. Unit of KB

, Weiglit ...,, „,.. 803

Watcm, Solvent power of ISA

Waxy .,...,. SS8

WeatheriEB of outcrop 161

Weight of ores ]S

WeiTB , 8H

West Point. Cal .,,..,, lOB

Wheai DolcoBth

Wheal Mary Ann HO. JJB

Willeciita. aia

Win? AM

WiBc>onsJaiiilnea i 115

Wolfram,, &T

Wood tin.. ., aSB

Forkine facfUtfes,,. IW

Works, rlaanintf SO

WorkaUnuuftahle... 6

Y

Taifl sne

YanVeeHill IDl

Yellow Jacket rntna 100

Z

Zinc and country rocks 137

Zinc at AlUinberg IIB

Kinfi carbonate 217

uc oieiirrenoefl 131

Zinc ores. 217

2:inc osdde 21B

Zinc silicate 217

iincblende. ...1 2l6

Zinclte £18

Zlac-lead. ..., ,, Wk

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