Stratigraphic sections of the Phosphoria formation in Montana

Swanson, R. W., Klepper, M. R., Lowell, W.R., Honkala, F.S. · 1951 · Report

The first of a series of reports giving detailed stratigraphic sections of the Phosphoria formation in the Western phosphate field as measured and described

This 1951 document, Stratigraphic sections of the Phosphoria formation in Montana, is preserved in the Mountain Man Mining Library for research and reference. Original source: pubs.usgs.gov.

UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY STRATIGRAPHIC SECTIONS OF THE PHOSPHORIA FORMATION IN MONTANA by R. W. Swanson, M. R. Klepper, W. R. Lowell, F. S. Honkala, E. R. Cressman, D. A. Bostwick, 0. A. Payne, and E. T. Ruppel MINERAL DEPOSITS BRANCH Spokane, Washington July 1951 $UOLOGICA/ ILSHINC.;Te) wiffr lu 19bi OPEN FILE ,.e.froP1 This -m.ttp is preliminary and has not conformity been edited or rc...7:1eEc'd vey standards with U. S. Geolc,:,ic3.1 Zu:'­ and nomenclature.,

TABLE OF CONTENTS Page Introduction Abstract of sections lm Graveley Mine. Lot no. 1286, Luke Mine. Lot no. 1285. 2m 3m Canyon Creek no. 1. Lot no. 1237. Canyon Creek no. 2. Lot no. 1238. Melrose Adit no. 2. Lot no. 1239. ... 4m 5m 6m Spectrographic analyses Melrose Adit no. 1. Lot no. 1240. 7m 8m South Greenstone Gulch. Lot no. 1250. 9m Upper French Creek. Lot no. 1248. Kelley Gulch. Lot no. 1249. Cave Creek. Lot no. 1257, Jack Canyon. Lot no. 1218. Spectrographic analyses Aspen Valley. Lot no. 1215. 1 lm lZm 1 5 m 17m 19m 20m Shell Canyon. Lot no. 1214. . 21m West Fork of Gallatin River. Lot no. 1216... 23m Porcupine Creek. Lot no. 1217. 24m Daly' s Spur. Lot nos. 122 and 1Z23. 25m Sheep Creek. Lot no. 1234. 28m Spectrographic analyses 32m Oil shale analyses 35m ' Cedar Creek. Lot no. 1256. . 37m Sawtooth Peak. Lot no. 1241. 39m

TABLE OF CONTENTS (CONT' D.) Page Abstract of sections (cont' d.) Hidden Pasture Creek, Muddy Creek, and Big Sheep Canyon. Lot nos. 1224, 1225, 1226, and 1227. 43m Additional analyses of sample OAP-150-47 49m Wadham Springs. Lot nos. 1246 and 1247. 50m Centennial Range Trench no. 4. Lot no. 1251. . 53m Odell Creek. Lot no. 1252. 54m Centennial Range Trench no. 1. Lot no. 1253. 56m Centennial Range Trenches nos. 2 and 3, (Montana-Idaho). Lot nos. 1254 and 1255. 58m Additional analyses of sample OAP-50547. 60m

STRATIGRAPHIC SECTIONS OF THE PHOSPHORIA FORMATION IN MONTANA by R. W. Swanson, M. R. Klepper, W. R. Lowell, F. S. Honkala, E. R. Cressman, D. A. Bostwick, 0. A. Payne, and E. T. Ruppel INTRODUCTION The first of a series of reports giving detailed stratigraphic sections of the Phosphoria formation in the Western phosphate field as measured and described by the Geological Survey will be released as Circulars within the next few months, Because of the needs of industry for many of these data during the 1951 field season, and in view of the unavoidable delays attendant on publi­ cation, the tabular data to be included in these Circulars are hereby placed on open file in simple reproduction form (prepared by Ozalid from photographic negatives) and without explanatory text so that immediate use may be made of the data. The tables include data on sections in four states: Montana, Idaho, Wyoming, and Utah; and the tables for each of these states are bound together as individual reports. The tables include name and location of section measured, brief description of geologic setting, acknowledgments for field and analytical work, abstract data on the sections (bed number, rock name, sample number, and thick­ ness), and analytical data on the samples. The analytical data include reports on P205 and acid insoluble for all samples and additional analyses, such as A1,03, Fe2O3, loss on ignition, F, and V205, for selected samples. Spectrographic analyses for a barge number of elements are included for samples from selected localities, and special analyses have been made of a few samples. The work in Montana has been done with the aid of Missouri River Basin funds as part of a Program of appraisal of the Missouri Basin mineral resources. These reports are placed on open file at the offices of the Geological Survey in Washington, D. C., Spokane, Washington, Salt Lake City, Utah, and Montpelier, Idaho, and at the offices of the Idaho Bureau of Mines and Geology, Moscow, Idaho, the Montana Bureau of Mines and Geology, Butte, Montana, the Wyoming Geological Survey, Laramie, Wyoming, and the University of Utah, Salt Lake City, Utah.

ANDERSON MINE, MONTANA. LOT NO. 1287. D member of Phosphoria formation sampled at 4,800 level of Anderson mine of Montana Phosphate Products Company, secs. 2 and 3. T. 10 N., R. 10 W., Powell County, Montana, on southwest flank of Garrison anticline, samples 308-313, locality A, from 100 feet south of north heading and sample 314, locality B, from 150 feet south of crosscut. Beds strike about N. 30° W., and dip 30° SW. Section measured and sampled by M. R. Klepper in October 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness z Bed Sample Thickness rcent Rock description thickness no. no. (feet) Aci (feet) percent P (cumulative, P205 insoluble Locality A, 4,800 level, 100 feet south of north heading E member of Phosphoria formation--basal beds only E-2.1 Quartzite E-1 Conglomerate D member of Phosphoria formation D-8 Clay D-7 Phosphate rock, argillaceous MRK-313 20.85* D-6 Phosphate rock MRK-312 D-5 Phosphate rock MRK-311 D-4 Phosphate rock MRK-310 D-3 Phosphate rock MRK-309 D-2 Phosphate rock MRK-308 152.35** D-1 Clay C member of Phosphoria formation-top beds only Conglomerate Sandstone Locality B, 4,800 level, 150 feet south of crosscut E member of Phosphoria formation-not measured E­ 711 Chert Cumulative data incomplete due to missing information. '6* Note incompleteness of cumulative data.

Chemical analyses Cumulative Thickness z Bed Sample Thickness (percent) Rock description thickness percent P2205 no. (feet) Acid no. (feet) (cumulative] insoluble D member of Phosphoria formation D- I Phosphate rock MRK-314 Composite sample representing beds D-Z to D-7 of locality A. C member of Phosphoria formation—top beds only Quartzite .. MO Conglomerate Clay Sandstone and chert

GRAVELEY MINE, MONTANA. LOT NO. 1286. D member of Phosphoria formation sampled in Graveley Mine of Montana Phosphate Products Company, sec. 2, T. 10 N., R. 9 W., Powell County, Montana, on northeast side of Luke-Graveley syncline; samples 297-299, locality A, from 4,906 stope and samples 300-303, locality B, from 5,101 west heading. Beds strike about N. 70° W. and dip 50° S. Section measured and sampled by M. R. Klepper in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description Sample no. Thickness (feet) Chemical analyses (percent P2O5 insoluble Cumulative thickness (feet) Thickness x percent P2O5 (cumulative) Locality A, 4,906 stope E member of Phosphoria formation-not measured E-1 Chert D member of Phosphoria formation D-5 D-4 D-3 D-2 D-1 Clay Phosphate rock Phosphate rock Phosphate rock Clay

MRK-299 MRK-298 MRK-297 45.50* 129.75** C member of Phosphoria formation-not measured C-1 Quartzite Locality B, 5,101 west heading E member of Phosphoria formation-not measured E-1 Chert D member of Phosphoria formation D-5 D-4 D-3 D-2 D-1 Clay Phosphate rock Phosphate rock Phosphate rock Clay MRK-303 MRK 302 MRK-301 44. 16* 109. Cumulative data incomplete due to missing information. Note incompleteness of cumulative data.

Chemical analyses Cumulative Thickness z Bed Sample Thickness (percent Rock description thickness percent P,05 no. no. (feet) Acid (feet) (cumulatiVel P2°5 ; insoluble C member of Phosphoria formation—top beds only Conglomerate MRK-300 Sandstone Quartzite sj3/4 4 V1.

LUKE MINE, MONTANA. LOT NO. 1285. D member of Phosphoria formation sampled in Luke Mine of Montana Phosphate Products Company, sec. 15, T. 10 N., R. 9 W., Powell County, Montana, on southwest side of Luke-Graveley syncline; samples 304-305, locality A, from southeast heading, 5,300 level, samples 306-307, locality B, from northwest heading, 5,300 level. Beds strike about N. 40° W. and dip 45° NE. Section measured and sampled by M. R. Klepper in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description E-1 Quartzite, cherty D-4 Clay D-3 Phosphate rock D-2 Phosphate rock D-1 Clay C-2 Quartzite C-1 Quartzite E-1 Quartzite D-2 Phosphate rock D-1 Phosphate rock Quartzite Conglomerate Chert Chemical analyses Sample Thickness rcent no. (feet) Cl' P2O5 insoluble Locality A, 5,300 level, southeast heading E member of Phosphoria formation-basal bed only D member of Phosphoria formation MRK-305 MRK-304 C member of Phosphoria formation-top beds only Locality 13, 5,300 level, northwest heading E member of Phosphoria formation-basal bed only D member of Phosphoria formation MRK-307 MRK-306 C member of Phosphoria formation-top beds only Cumulative thickness (feet) Thickness x percent P OS (cumulative/ 111.2**

Note incompleteness of cumulative data.

CANYON CREEK NO. I, MONTANA. LOT NO. 1237. D member of Phosphoria formation sampled in hand trench near Canyon Creek, SE; sec. 12, T. 2 S., R. 10 W., Beaverhead County, Montana, on west limb of an overturned anticline. Beds strike N. 60° W. and dip 50° SW. Section measured by M. R. 'Klepper and sampled by E. T. Ruppel in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed Chemical anal ses (percent Cumulative Thickness x Sample Thickness no. Rock description oss on thickness percent P,05 no. (feet) P 0 Al 0 Fe 0 ignition insoluble (feet) (cumulatiVel E member of Phosphoria formation-basal bed only Chert MRK-270 D member of Phosphoria formation-base not exposed D-5 Phosphate rock MRK-269 D-4 Mudstone, calcareous and phosphate rock MRK-268 D 3 Phosphate rock MRK-267 D-2. Mudstone and phosphate rock MRK-266 D-1 Mudstone, phosphatic MRK-265 Or\

CANYON CREEK NO. 2, MONTANA. LOT NO. 1238. D member of Phosphoria formation sampled in hand trench near Canyon Creek, EISE; sec. 6, T. 2 S., R. 9 W., Beaverhead County, Montana, on overturned east limb of an anticline. Beds strike N. 5-10° W. and dip 700 W. Section measured by M. R. Klepper and sampled by E. T. Ruppel in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical anal sesApercent) Cumulative Thickness x Bed Sample Thickness Rock description FYLoss on Acid thickness percent P,05 no. no. (feet) A1203 Fe 0 P205 2 3ignition insoluble (feet) (cumulatilrei E member of Phosphoria formation—basal bed only jQuartzite and conglomerate D member of Phosphoria formation—base not exposed D-4 Mudstone D-3 Phosphate rock and mudstone MRK-273 57.30* D-2 Phosphate rock and mudstone MRK-272 3S. 0 D-1 Phosphate rock MRK-271 222.28** Cumulative data incomplete due to missing information. Co Note incompleteness of cumulative data.

MELROSE ADIT NO. 2, MONTANA. LOT NO. 1239. D member of Phosphoria formation sampled in an adit of the Anderson Phosphate Mines, Incorporated, of Butte, Montana, known as the Melrose Property, in NW* sec. 5, T. 2 S., R. 9 W.. Silverbow County, Montana, on the normal limb of a northwest-trending overturned syncline. Beds D-6 through D-11 sampled at heading of a south-southeast drift approximately 1,400 feet from portal; beds D-1 through D- 5 sampled 36 feet from heading. Beds strike northwest and dip 45' SW. Section measured by M. R. Klepper and 0. A. Payne and sampled by Payne in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical anal ses ( . rcent Cumulative Thickness x Bed Sample Thickness oss on ci thickness percent P0 Rock description A1203 Fe2O3 F no. no. (feet) P205 e23 ignition insoluble (feet) (cumulative) E- 1 Chert and conglomerate D member of Phosphoria formation Mudstme Phosphate rock, argillaceous MRK-293 29.90* Phosphate rock and calcareous mudstone MRK-292 1 - 8 Phosphate rock MRK-291 Mudstone MRK-290 Phosphate rock MRK-289 " 5 Idudatone, calcareous MRK-288 1- 4 Phosphate rock MRK-287 /- 3 Mudstone and phosphate rock MRK-286 - 2 Phosphate rock MRK-285 1 Phosphate rock, argillaceous KIRK-284 303.88** Cumulative data incomplete due to missing information. Note incompleteness of cumulative data.

SPECTROGRAPHIC ANALYSES—MELROSE ADIT NO. Z. MONTANA. LOT NO. 1239. Semi-quantitative analyses of samples of the D member of Phosphoria formation, Melrose adit no. 2, Montana (see immediately preceding page for location of section, thickness and description of strata, and chemical analyses of samples), made by U. S. Bureau of Mines Laboratory, Albany, Oregon. In addition to the elements listed in the table below, Sb, As, Ba, Be, Bi, Cd, Co, Cb, Ga, Ge, Au, In, Pb, Li, Hg, Pt, Ta, Sn, and W were looked for in all samples but were not detected. Explanation of symbols A more than 10 percent E 0.01-0.1 percent B 5-10 percent F 0.001-0.01 percent C 1-5 percent G less than 0.001 percent D 0.1-1 percent Bed no. Sample no. Al B Ca Cr Cu Fe Mg Mn Mo Ni Si Ag Na Sr Ti Zn Zr D-11 D-10 D- 9 MRK-294 MRK-293 MRK-292 MRK-291 B B E F F F A A A D E E E F G G G A E E E E F F F F E E E E A B B A G G G G E E E E F E E E E D E D E E E E E E E E E E E D' 7 MRK-290 B E B E G A E F E A G E F D E E E MRK-289 F A E G D E F E G E E E D E E D" 5 MRK-288 B F A D G A A E E D A E F D D E E MRK-287 B F A E G F F E A F E E D D E E D- 3 MRK-286 B F A E G F F E A F E E D D E E D' 2 MRK-285 F A E G D F F E G E E E D E E D- 1 MRK-2.84 B F A D G F E A G E E D D E E

MELROSE ADIT NO. 1, MONTANA. LOT NO. 1240. D member of Phosphoria formation sampled in southwest crosscut 269 feet from portal of the Anderson Phosphate Mines, Incorporated, of Butte, Montana, known as the Melrose Property, NW; sec. 5, T. 2 S., R. 9 W., Silver Bow County, Montana, on normal limb of overturned syncline. Beds strike northwest and dip 45° SW. Section measured by M. R. Klepper and 0. A. Payne and sampled by Payne in September 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical anal ses .-rcent Cumulative Thickness x Bed Sample Thickness no. Rock description oss On ci thickness percent P 0 no. (feet) P205 A1203 ignition insoluble (feet) (CUMulativei E member of Phosphoria formation-basal bed only E- 1 Chert D member of Phosphoria formation D-10 Conglomerate and phosphate rock MRK-283 D- 9 Mudstone MRK-282 D- 8 Phosphate rock MRK-Z81 Z. 16 Z. 3 D- 7 Mudstone D- 6 Phosphate rock, argillaceous MRK-280 19.28* DMudstone MRK-Z79 13.00 6.29 D- 4 Phosphate rock MRK-278 D- 3 Phosphate rock MRK- 277 DPhosphate rock MRK-276 Z. 70 232. Base of D-2 is a gougy fault zone of several strands cutting dark mudstone and phosphate rock. DPhosphate rock, argillaceous MRK-Z75 C member of Phosphoria formation--top bed only Dolomite and chert Cumulative data incomplete due to missing information. Corn -tations start from zero after interruption. Note incompleteness of cumulative data.

SOUTH GREENSTONE GULCH, MONTANA. LOT NO. 1250. D member of Phosphoria formation sampled in south bulldozer trench at Greenstone Gulch, SE* sec. 11, T. 5 S., R. 9 W., Beaverhead County, Montana. Beds strike N. 10" W. and dip 50 - NE. The stratigraphic sequence of the units is questionable for, because of a large number of faults, some of the beds may be omitted or repeated. Section measured and sampled by R. L. Parker and E. R. Cressman in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness x Bed Sample 1 Thickness (percent) Rock description thickness percent P705 no. no. I (feet) Acid P 0 (feet) (cumulatiVel insoluble t E member of Phosphoria formation-basal bed only E- 1 Quartzite ERC-446 2.2? D member of Phosphoria formation D-37 Mudstone ERC-445 D-36 Mudstone RLP-444 D-35 Mudstone RLP-443 D-34 Mudstone RLP-442 D-33 Mudstone, calcareous ALP-441 D-32 Mudstone, calcareous, phosphatic RLP-440 D-31 Mudstone, phosphatic ERC-439 D-30 Phosphate rock ERC-260 D-29 Mudstone, phosphatic ERC-259 D-28 Mudstone ERC-258 D-27 Mudstone, phosphatic ERC-257 le -26 Mudstone, calcareous ERC-256 Mudstone, calcareous ERC-255 ie -24 Limestone, argillaceous ERC-254 Mudstone, calcareous, and phosphatic mudstone ERC-253 :1-22 Mudstone and phosphate rock RLP-252 a -21 Mudstone and phosphate rock RLP-251 0.8? '0-20 Mudstone RLP-250 '0-19 Phosphate rock RLP-249 B -18 Phosphate rock and mudstone RLP-248 o -17 Phosphate rock, argillaceous RLP-247 Phosphate rock and mudstone, cherty RLP-246 Mudstone, calcareous and, and calcareous phosphate rock RLP-245 Limestone RLP-244 Phosphate rock and mudstone RLP-243 Mudstone, phosphatic RLP-242

Chemical analyses Cumulative Thickness x Bed .ample Thickness (percent Rock description thickness percent P no. no. (feet) ea P205 insoluble (feet) (cturulativel D-11 Limestone RLP- 241 D-10 D- 9 D- 8 Phosphate rock and mudstone, cherty Mudstone, phosphatic, calcareous Limestone, argillaceous, phosphatic RLP-240 RLP-239 ERC-238 D- 7 D- 6 D- 5 D- 4 D- 3 Mudstone, phosphatic Mudstone, calcareous Mudstone, phosphatic Limestone, argillaceous, phosphatic Phosphate rock, argillaceous ERC-237 ERC- 236 ERC-235 ERC-234 RLP-233 D- 2 D- 1 Phosphate rock and mudstone, cherty Chert, phosphatic RLP- 232 RLP-231 C member of Phosphoria formation-top bed only C- 1 Mudstone, calcareous RLP- 230

UPPER FRENCH CREEK, MONTANA. LOT NO. 1248. D member of Phosphoria formation sampled in bulldozer trench near Upper French Creek, SWI-sec. 19, T. 5 S., R. 10 W., Beaverhead County, Montana. Beds strike N. 15° E. and dip 55" W. The stratigraphic sequence and thicknesses of the units are questionable due to thrust faulting exposed in the trench and to the fragmented and weathered condition of the strata. Section measured by D. A. Bostwick and R. L. Parker and sampled by R. L. Konizeski and J. E. Joyce in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Bed Cumulative Thickness x Sample Thickness (percent) no. Rock description thickness percent P705 no. (feet) Acid P2O5 (feet) (cumulatiVei insoluble D member of Phosphoria formation-top not exposed D-10 Phosphate rock, argillaceous RLP-172 D- 9 Mudstone, phosphatic RLP-171 D- 8 Phosphate rock and mudstone RLP- 170 D- 7 Phosphate rock and mudstone, cherty RLP- 169 D- 6 Mudstone RLP- 168 D- 5 Mudstone RLP-167 D- 4 Mudstone DAB-166 D- 3 Mudstone DAB-165 D- 2 Mudstone, calcareous DAB-164 D- I Mudstone, calcareous DAB-163 Probable fault; units below may be part of a fault zone. C member? of Phosphoria formation-top and base not exposed C- 5 Quartzite and chert DAB-162 ? C- 4 Quartzite and chert DAB-161 ? C- 3 Quartzite and chert DAB-160 1.5? C- 2 Chert DAB-159 C- 1 Sandstone and chert DAB-158 Thrust fault Quadrant formation -not measured Cq- 1 Quartzite

KELLEY GULCH, MONTANA. LOT NO. 1249. A, B, D, and part of E members of Phosphoria formation sampled in bulldozer trenches and C member measured in outcrops near Kelley Gulch, sec. 2, T. 6 S., R. 11 W., Beaverhead County, Montana. A dacitic? sill 2.7 feet thick occurs 2.1 feet above base of E member. Beds strike N. 25° E. and dip 45' NW. Section measured by R. L. Parker and D. A. Bostwick and sampled by R. L. Konizeski, J. E. Joyce, Bostwick, J. A. Kelleher, and E. T. Ruppel in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany. Oregon. Chemical analyses Cumulative Thickness x Bed Sample Thickness ercent Rock description thickness percent P2O5 no. no. (feet) (feet) (cumulative P205 insoluble Dinwoody formation-not exposed E member of Phosphoria formation-top contact approximately located E- 9 Chert E- 8 Chert E- 7 Chert E- 6 Chert E- 5 Chert, sandy? E- 4 Mudstone DAB-229 E- 3 Chert DAB-228 E- 2 Chert DAB-227 Dacitic? dike DAB-226 (2.7) E- 1 Chert DAB-225 D member of Phosphoria formation D-38 Chert; fos. col. no. 48-KPM-511 DAB-224 ,.4 D-37 Phosphate rock, cherty and mudstone RLP-223 Fault zone; includes gougy streaks and crushed phosphate. D-36 D-35 D-34 Fault gouge and breccia Mudstone Phosphate rock, cherty RLP-222 RLP-221 RLP-220 D-33 D-31 D-30 Mudstone and phosphate rock Mudstone Mudstone Mudstone RLP-219 RLP-218 DAB-217 DAB-216 9 -29 Mudstone DAB-215 i9 -28 Mudstone DAB-214 9 -27 Mudstone DAB-213 Mudstone DAB-212

D-25 Mudstone D-24 Mudstone D-23 Mudstone and phosphate rock D-22 Mudstone, calcareous D-21 Dolomite, phosphatic D-20 Phosphate rock D-19 Limestone D-18 Phosphate rock and dolomite D-17 Limestone D-16 Mudstone, phosphatic, calcareous D-15 Phosphate rock, argillaceous; fos. col. no. 48- KPM - 50 D-14 Mudstone, phosphatic D-13 Phosphate rock, argillaceous D-12 Phosphate rock, argillaceous D-11 Mudstone, phosphatic D-10 Mudstone, phosphatic D- 9 Mudstone D- 8 Mudstone, phosphatic D- 7 Limestone, argillaceous D- 6 Mudstone D- 5 Mudstone, cherty D- 4 Mudstone, phosphatic D- 3 Mudstone, phosphatic D- 2 Mudstone, cherty D- 1 Mudstone, phosphatic, cherty C- 2 Chert and quartzite, calcareous C- 1 Dolomite, cherty B- 4 Chert and sandstone B- 3 Phosphate rock, cherty B- 2 Chert, phosphatic and phosphate rock B- 1 Quartzite and chert A- 9 Mudstone A- 8 Mudstone, calcareous - 7 Sandstone A- 6 Sandstone, calcareous - 5 Mudstone, calcareous and sandstone - 4 Mudstone DAB-211 DAB-210 DAB- 209 DAB- 208 DAB-207 DAB-206 DAB- 205 DAB-204 DAB-203 DAB- 202 DAB-201 DAB-200 RLP- 199 RLP-198 RLP-197 RLP-196 RLP-195 RLP- 194 RLP- 193 RLP-192 RLP-191 RLP-190 RLP-189 RLP- 188 DAB- 187 C member of Phosphoria formation B member of Phosphoria formation DAB-186 RLP- 185 RLP-184 RLP-183 A member of Phosphoria formation DAB-182 DAB-181 DAB-180 DAB-179 RLP-178 RLP-177 72, 6 Fossil collection made by K. P. McLaughlin, Paleontology and Stratigraphy Branch, U. S. Geological Survey.

Chemical analyses Cumulative Bed Sample Thickness (percent) Thickness x Rock description thickness percent P,05 no. no. (feet) Acid (feet) (cumulatiVe) insoluble A- 3 A- 2 A- 1 Mudstone, calcareous, sandy Sandstone, cherty ? Mudstone and sandstone RLP- 176 DAB-175 DAB-174 1 19.1 j Quadrant formation Cq- 1 Sandstone, quartz itic DAB-173 AIL

CAVE CREEK, MONTANA. LOT NO. 1257. D member of Phosphoria formation sampled in bulldozer trench on south side of Cave Creek, NWINWI sec. 10, T. 6 S., R. 10 W., Beaverhead County, Montana, about 2,000 feet west of axis of northeastward plunging Cave Creek syncline. Beds strike N. 25° W. and dip 40 ° NE. Section measured by E. T. Ruppel and sampled by J. A. Kelleher in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical anal ses - rcent Cumulative Thickness x Bed Sample Thickness Rock description oss on ci thickness no. no. (feet) P 0 2O5 A1203 Fe Fe0 2O3 ignition insoluble (feet) percent P (cumulative 205/ Dinwoody formation-not exposed E member of Phosphoria formation-top approximately located E- 8 Chert and quartzite E - 7 Chen and quartzite E. 6 Chart and quartzite E- 5 Chart and quartzite E-- 4 Chert and quartzite " 3 Chart E- 2 Chart E" / Chert ETR-620 D member of Phosphoria formation -base not exposed Rhyolite? ETR-619 (5.25) Phosphate rock ETR-618 4-30 Phosphate rock, argillaceous ETR-617 Flow breccia? ETR-616 (1.2) Mudstone, phosphatic ETR-615 Mudstone ETR-614 " -27 Mudstone ETR-613 Mudstone, phosphatic ETR-612 Rhyolite sill? ETR-611 (2.3) -,- -2S Mudstone ETR-610

Phosphate rock ETR-609 Mudstone, phosphatic ETR-608 Phosphate rock, argillaceous ETR-607 Mudstone; fos. col. no. 48-KPM-561 ETR-608 Phosphate rock, argillaceous ETR-605 :19 Mudstone, phosphatic ETR-604 la Phosphate rock, argillaceous ETR-603

Phosphate rock ETR-602 1 Fossil collection made by K. P. McLaughlin, Paleontology and Stratigraphy Branch, U. S. Geological Survey.

Chemical analyses (percent) Cumulative Thickness x Bed Sample Thickness Rock description Loss on Acid thickness percent PO, no. no. (feet) A1203 Fe2O3 ignition insoluble (feet) (curnulatiVer D-16 Phosphate rock and phosphatic mudstone ETR- 601 D-15 Mudstone, phosphatic ETR -600 D-14 Mudstone, phosphatic ETR -599 D-13 Mudstone, calcareous; fos. col. no. 48 - KF'M - 55 ETR- 598 D-12 Phosphate rock, argillaceous ETR- 597 D-11 Mudstone, phosphatic, fos. col. no. 48-KPM- 54 ETR- 596 D- lo Phosphate rock, argillaceous ETR-545 Mudstone, phosphatic, fos. col. no. 48- KF'M -53 ETR -594 D- 8 Mudstone, phosphatic ETR -593 D- 7 Phosphate rock, argillaceous and mudstone; fos. col. no. 48-KF'M -52 ETR-592 0- 6 Mudstone, phosphatic ETR - 591 D- 5 Mudstone ETR -590 3209.. 7100 D- 4 Mudstone, phosphatic, calcareous ETR- 589 Mudstone ETR - 588 0.7? D- 2 Phosphate rock, argillaceous 'ETR -587 0- 1 Phosphate rock, sandy ETR- 586 Stratigraphic interval of 116 feet between 13-1 and approximate top of Quadrant quartzite includes few exposures of quartzite and Limestone.

JACK CANYON, MONTANA. LOT NO. 1218. Phosphoria formation sampled in hand trench and outcrop about 900 feet above Jack Creek on north side of canyon in SEI-NE; sec. 35, T. 5 S., R. 1 E., Madison County, Montana, on overturned and faulted west limb of Madison Range syncline. Beds strike N. 60° E. and dip 45' NW. Section measured by R. W. Swanson and sampled by J. G. Evans in September 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description Sample no. Thickness (feet) P 0 Chemical anal ses rcent oss on Aci Al 203 Fe 0 ignition insoluble Cumulative thickness (feet) Thickness x percent P,05 (cumulatiVel Dinwoody formation Mudstone, calcareous Sandstone, calcareous, argillaceous Phosphoria formation Chert and calcareous sandstone Sandstone, calcareous, and chert Sandstone, calcareous, and chert Chert, sandstone, and limestone Chert and quartzite RWS-107-47 RWS-106-47 RWS-105-47 RWS-104-47 RWS-103-47 Z. 6 MO 52,91 Sandstone Quartzite Chert and quartzite Chert and mudstone Chert and mudstone RWS-IO2-47 RWS-101-47 RWS-100-47 RWS- 99-47 RWS- 98-47 /5 !3 Chert and mudstone Phosphate rock, argillaceous Chert and mudstone Phosphate rock, argillaceous Chert and calcareous mudstone (may include 2.45 feet repetition by faulting) Cheri and mudstone Chert and mudstone Chert and mudstone Phosphate rock Limestone, argillaceous RWS- 97-47 RWS- 96-47 RWS- 95-47 RWS- 94-47 RWS- 93-47 RWS- 92-47 RWS- 91-47 RWS- 90-47 RWS- 89-47 RWS- 88-47 Z. 5

Feldspar porphyry Feldspar porphyry Sandstone, phosphatic, and phosphate rock Quartzite Quartzite, cherty RWS- 87-47 RWS- 86-47 RWS- 85-47 RWS- 84-47 RWS- 83-47 (3.0) (1.1) i Quartzite and chert Conglomerate, mudstone, and chert RWS- 82-47 RWS- 81-47 Z. 5

Chemical analyses (percent) Cumulative I Thickness x Bed Sample Thickness Rock description Loss on Acid thickness percent P2O5 no. no. (feet) P2O5 A1203 Fe2O3 ignition insoluble (feet) j (cumulative, Quadrant formation 9-1 Mudstone, calcareous, sandy, and argillaceous, calcareous sandstone RWS- 80-47 Q-2 Sandstone, quartzitic, cherty

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ASPEN VALLEY, MONTANA. LOT NO. 1215. Phosphatic shale member of Phosphoria formation sampled in hand trench near top of ridge on west side of Aspen Valley, SEiSEI sec. 11, T. 6 S., R. 1 E., Madison County, Montana, on overturned west limb of Madison Range syncline. Beds strike N. 45* E. and dip 550 NW. Section measured by R. W. Swanson and sampled by J. A. Mann and J. G. Evans in August 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses (percent) Cumulative Thickness x Bed Sample Thickness Rock description Acid thickness percent P2O5 no. no. (feet) P2O5 insoluble (feet) (cumulative) Phosphoria formation-top and base not exposed Sandstone Quartzite RWS-43-47 0.98* 18 Chert and mudstone RV/S-42-47 17 Chert and mudstone RWS-41-47 16 Chert and mudstone RWS-40-47 Mudstone RWS-39-47 Phosphate rock, cherty RWS-38-47 Limestone, argillaceous RWS-37-47 12 Chert and mudstone RWS-36-47 Chert and mudstone . RWS-35-47 10 Chert and mudstone RWS-34-47 Chert and mudstone RWS-33-47 Phosphate rock RWS-32-47 Phosphate rock RWS-31-47 Mudstone RWS-30-47 Limestone RWS-29-47 Mudstone, calcareous RWS-28-47 Phosphate rock and mudstone RWS-27-47 Phosphate rock and phosphatic sandstone RWS-26-47 / Sandstone RWS-25-47 199.35** Cumulative data incomplete due to missing information. Note incompleteness of cumulative data. ").. 0 1N1 11

SHELL CANYON, MONTANA. LOT NO. 1214. Phosphoria formation measured and phosphatic shale member sampled in hand trench and outcrop on north side of Shell Creek canyon, SWINE; sec. 33, T. 6 S., R. 1 E., Madison County, Montana, near crest of small dome at west side of Madison Range syncline. Beds strike N. 5° W. and dip 12° W. Section measured by R. W. Swanson and sampled by J. A. Mann and J. G. Evans in August 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses (percent) I Cumulative Thickness x Bed Sample Thickness Rock description Acid thickness percent P2O5 no. no. (feet) P 0 insoluble 1 (feet) (cumulative/ Dinwoody formation itd-1 Limestone Phosphoria formation 43 Sandstone, calcareous, cherty

Sandstone, calcareous, cherty 4/

Chert and sandstone Quartzite Limestone, cherty .3, 13 Chert and quartzite

: Chert and quartzite 'S Quartzite

' 4 Quartzite and chert 3,3 Quartzite :.2 Sandstone and chert

-/ ,) Chert, contains sandstone lenses

Sandstone, quartzitic 49 Sandstone, quartzitic, cherty

Chert and quartzitic sandstone

1.12* 7 Chert and quartzite RWS-24-47 Chert RWS-23-47 , Chert, contains thin mudstone partings RWS-22-47 VD .. `4 Chert, contains thin mudstone partings RWS-21-47 Z3 Chert, contains thin mudstone partings RWS-20-47 22 Chert, contains thin mudstone partings RWS- 19-47

Mudstone, calcareous RWS-18-47 20 Phosphate rock, cherty RWS-17-47 / 9 Mudstone. calcareous RWS-16-47 Mudatone. calcareous RWS-15-47 72,0 litedstone, cherty, calcareous RWS-14-47 Cumulative data incomplete due to missing information.

Bed no. Rock description Sample no. Thickness (feet) Chemical analyses (percent Cumulative thickness (feet) Thickness x percent P05 (cumulative P 205 F insoluble Mudstone RWS-13-47 Phosphate rock, argillaceous RWS-12-47 Phosphate rock RWS-11-47 Phosphate rock RWS-10-47 Mudstone RWS- 9-47 Limestone, argillaceous RWS- 8-47 Mudstone, calcareous RWS- 7-47 Mudstone, calcareous RWS- 6-47 Mudstone and phosphate rock RWS- 5-47 Sandstone, quartzitic, phosphatic and chert RWS- 4-47

Sandstone, quartzitic RWS- 3-47 Sandstone, quartzitic RWS- 2-47 Sandstone, quartzitic RWS- 1-47 146.79** Sandstone, quartzitic Chert Sandstone, quartzitic and chert Quadrant formation Cq-1 Limestone, cherty eq-2. Sandstone, quartzitic Note incompleteness of cumulative data.

WEST FORK OF GALLATIN RIVER, MONTANA. LOT NO. 1216. Part of Phosphoria formation sampled in hand trench and outcrops on slope north of West Fork of Gallatin River, NW.'-SE; sec. 32, T. 6 S., R. 4 E., Gallatin County, Montana, from strata dragged up beneath Gardiner thrust fault. Beds strike N. 35° W. and dip 45-50° SW. Section measured by R. W. Swanson and sampled by J. A. Mann and J. G. Evans in September 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description 25 Sandstone, quartzitic and chert 24 Quartzite, contains chert concretions Limestone, contains chert concretions 22 Chert and quartzite Chert, quartzite, and mudstone 20 Quartzite Chert and mudstone 18 Chert and mudstone 17 Chert and mudstone

Mudstone, phosphatic Mudstone Mudstone Mudstone Mudstone Phosphate rock, argillaceous Phosphate rock, argillaceous 9 Sandstone, phosphatic Sandstone Mudstone, contains qua rtzitic sandstone concretions 6 Chert, calcareous mudstone, and quartzite 5 Quartzite, cherty Mudstone, sandy, contains quartzitic concretions 3 )mudstone, calcareous and quartzite 2 Sandstone, quartzitic Quartzite Chert Cq2 Chert and sandstone Chemical analyses Sample Thickness ercent no. (feet) P2O5 insoluble Phosphoria formation-lower part only Cumulative thickness (feet) Thickness x percent P0 (cumulative,5 7.08* 80.83** RWS-63-47 RWS-62-47 RWS-61-47 RWS-60-47 RWS- 59-47 RWS - 58-47 RWS-57-47 RWS-56-47 RWS-55-47 RWS- 54-47 RWS-53-47 RWS-52-47 RWS-51-47 RWS-50-47 RWS -49-47 RWS-48-47 RWS-47-47 RWS-46-47 RWS-45-47 RWS-44-47 Quadrant formation Cumulative data incomplete due to missing information. Note incompleteness of cumulative data. )

PORCUPINE CREEK, MONTANA. LOT NO. 1217. Part of Phosphoria formation sampled in hand trench and outcrops on slope 11 miles north of Porcupine Creek, NEISEI sec. 10, T. 7 S., R. 4 E., Gallatin County, Montana, from strata dragged up beneath Gardiner thrust fault. Beds strike N. 40' W. and dip 754 SW. Section measured by R. W. Swanson and sampled by J. A. Mann and J. G. Evans in September 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness x Bed Sample Thickness ercent Rock description thickness percent P 05 no. no. (feet) ci (feet) (cumulatrvel P2O5 insoluble Phosphoria formation-lower part only 20 Sandstone 19 Chert, contains sandstone lenses

18 Sandstone 17 Sandstone, quartzitic RWS -79 -4 7 0.96* 16 Chert, contains mudstone partings RWS-78-47 15 Chert, contains mudstone partings RWS-77-47 14 Chert, contains mudstone partings RWS-76-47 13 Chert, contains mudstone partings RWS-75-47 12 Chert, contains mudstone partings RWS-74-47 Chert, contains mudstone partings RWS-73-47 10 Chert, contains mudstone partings RWS-72-47 9 Sandstone RWS-71-47 Mudstone, calcareous RWS - 70-47 7 Limestone, argillaceous RWS-69-47 6 Mudstone RWS -68-47 Z.9 Phosphate rock and mudstone RWS-67-47 4 Limestone, contains sandstone concretions RWS-66-47 Mudstone, contains sandstone concretions RWS-65-47 2 Sandstone, quartzitic RWS-64-47 54.65 Sandstone Quadrant formation Cq-1 Sandstone

Cq-2 Sandstone and chert Cq-3 Sandstone Cumulative data incomplete due to missing information. Note incompleteness of cumulative data.

DALY'S SPUR, MONTANA. LOT NOS. 1222 AND 1223. Phosphoria formation sampled near Daly' s Spur, west side of Beaverhead River; A, B, C, and E members, lot no. 1223, sampled in band trench and natural exposures, SW;;SWI sec. 36; and D member, lot no. 1222, in hand trench, Nilila-SWI sec. 36, T. 8 S., R. 10 W., Beaverhead County, Montana. Beds strike north to N. 30° E. and dip 30-40° W. Section measured by W. R. Lowell and sampled by D. A. Bostwick, R. L. Parker, and E. T. Ruppel in July 1937. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses (percent) Cumulative Thickness x Bed Sample Thickness Rock description Acid thickness no. no. (feet) F P205 insoluble (feet) percent P (cumulative/ Dinwoody formation-base not exposed E member of Phosphoria formation, lot no. 1223 -top not exposed Dinwoody-Phosphoria contact concealed by basalt flow, estimated thickness of covered E member E-10 Quartzite WRL-286-47 52. 14* E- 9 Chert WRL-285-47 E- 8 Quartzite, chert, and sandstone WRL-284-47 E- 7 Chert, sandy WRL-283-47 E- 6 Chert, sandy WRL-282-47 E- 5 Chert WRL-281-47 E- 4 Chert, sandy WRL-280-47 E- 3 Mudstone, contains gypsum WRL-279-47 E- 2 Chert WRL-278-47 E1 Quartzite, cherty, phosphatic WRL -277-47 . 232.60** Chert WRL- 46-47 WRL-46-47 is correlative with WRL-277-47 but occurs in same trench as D member. D member of Phosphoria formation, lot no. 1222 Mudstone WRL- 45-47 Mudstone WRL- 44-47 Z. 3 ' 5 -43 Mudstone WRL- 43-47 Phosphate rock, argillaceous WRL- 42-47 Mudstone, phosphatic WRL- 41-47 Phosphate rock, argillaceous WRL- 40-47 Mudstone, phosphatic WRL- 39-47 Phosphate rock and phosphatic mudstone WRL- 38-47 "37 Mudstone, calcareous WRL- 37-47 Phosphate rock, argillaceous WRL- 36-47 Cumulative data incomplete due to missing information. Note incompleteness of cumulative data.

Bed no. Rock description Sample no. Thickness (feet) Chemical anal ses F P205 ercent ci insoluble Cumulative thickness (feet) Thickness x percent P 7 05 (cumulatiVei D-35 D-34 D-33 D-32 D-31 Mudstone, phosphatic Mudstone Phosphate rock, argillaceous Mudstone, calcareous Phosphate rock, argillaceous WRL- 35-47 WRL- 34-47 WRL- 33-47 WRL- 32-47 WRL- 31-47 D-30 D-29 D-28 D-27 D-26 Mudstone, calcareous Mudstone, calcareous mudstone, calcareous Mudstone, calcareous Mudstone, calcareous WRL- 30-47 WRL- 29-47 WRL- 28-47 WRL- 27-47 WRL- 26-47 D-25 D-24 D-23 D-22 D­21 Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous WRL- 25-47 WRL- 24-47 WRL- 23-47 WRL- 22-47 WRL- 21-47 D-20 D-19 D­ 18 D­17 D­16 Mudstone Mudstone, calcareous Phosphate rock Mudstone, calcareous Phosphate rock WRL- 20-47 WRL- 19-47 WRL- 18-47 WRL- 17-47 WRL- 16-47 3,8 b. 7 D-15 D-14 D-13 D-12 D-11 Mudstone, calcareous Phosphate rock, argillaceous Limestone Mudstone, phosphatic Phosphate rock and mudstone WRL- 15-47 WRL- 14-47 WRL- 13-47 WRL- 12-47 WRL- 11-47 D-10 D- 9 „ ii,.,- 7 U- 6 Mudstone and phosphate rock Phosphate rock, argillaceous Mudstone, calcareous Mudstone and phosphate rock Mudstone WM.- 10-47 WRL9-47 WRL8-47 WRL7-47 WRL6-47 D- S Phosphate rock, argillaceous Phosphate rock, argillaceous, contains gypsum Mudstone, phosphatic, contains gypsum Mudstone Mudstone, phosphatic WRLWRL - WRLWRLWRL5-47

C member of Phosphoria formation, lot no. 1223 Z. 2 Sandstone WRL-276-47 WRL-275-47 C"10 Sandstone and chert 'PC-A

C- 9 Sandstone, calcareous WRL-274-47 C- 8 Sandstone WRL-273-47 C- 7 Chert and sandstone WRL-272-47 C- 6 Sandstone and cherty mudstone WRL-271-47 C- 5 Sandstone and chert WRL-270-47 C- 4 Sandstone WRL-269-47 C- 3 Sandstone, cherty WRL-268-47 Sandstone and chert WRL-267-47 C- 1 Sandstone and chert WRL-266-47 B member of Phosphoria formation, lot no. 1223 B- 5 Mudstone WRL-265-47 B- 4 Mudstone WRL-264-47 B- 3 Phosphate rock WRL -263-47 B- 2 Mudstone WRL-262-47 B- 1 Phosphate rock WRL-261-47 A member of Phosphoria formation, lot no. 1223 Sandstone WRL -260-47 Sandstone and mudstone WRL-259-47 Sandstone, cherty WRL-258-47 Mudstone WRL-257-47 Sandstone, calcareous WRL-256-47 Limestone WRL-255-47 Mudstone WRL-254-47 Limestone WRL-253-47 Mudstone WRL-252-47 Limestone WRL-251-47 Quadrant formation Thickness of Quadrant formation exposed in cliff

SHEEP CREEK, MONTANA. LOT NO. 1234. Phosphoria formation sampled in two bulldozer trenches near Sheep Creek Canyon, NW-ISW-I sec. 23, T. 9 S., R. 9 W., Beaverhead County, Montana, on west side of Small Horn Canyon anticline. Beds strike N. 23-41' E. and dip 30-45' NW. Section measured by L. A. Thomas, E. R. Cres­ sman, 0. A. Payne, V. E. McKelvey, D. A. Bostwick, F. S. Honkala, and J. E. Smedley and sampled by W. H. Wilson, Payne, R. L. Konizeski, Thomas, and Cressman in June 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses (percent) Cumulative Thickness x Bed Sample Thickness Rock description Loss on Acid thickness no. (feet) A1203 Fe2O3 ignition insoluble (feet) percent P (cumulative/ no. Dinwoody formation Mudstone, calcareous DAB- 80 E member of Phosphoria formation Sandstone; fos. col. no. 48-KPM-43 DAB- 79 Mudstone and chert LAT- 78 Chert and mudstone LAT- 77 Sandstone, chert, and mudstone; fos. col. no. 48-KPM- 42 LAT- 76 Sandstone and cher! ERC- 75 Sandstone and chert ERC- 74 Sandstone ERC- 73 Mudstone and chert DAB- 72 Mudstone DAB- 71 Sandstone and chert DAB- 70 Sandstone, phosphatic; fos. col. no. 48-KPM-41 DAB- 69 D member of Phosphoria formation 1)-48 Mudstone, phosphatic VEM- 1 Mudstone; fos. col. no. 48-KPM-40 VEM- 2 1).46 Mudstone, phosphatic; fos. col. no. 48-KPM -39 VEM- 3 D-45 Mudstone; fos. col. no. 48-KPM-38 VEM- 4 b-44 Mudstone JES - 5 D-43 Mudstone JES - 6 Mudstone, phosphatic JES - r)-41 Mudstone, phosphatic JES - 8 D-40 Phosphate rock, argillaceous OAP- 9 Mudstone and phosphate rock OAP-385 (0.3) OAP-385 represents the same bed as OAP-9 but was collected from a more weathered zone. Mudstone OAP- 10 Phosphate rock, argillaceous OAP- 11

D-37 Mudstone OAP- 12 D-36 Phosphate rock, argillaceous OAP- 13 D-35 Phosphate rock, argillaceous LAT- 14 Phosphate rock, argillaceous LAT-386 (0.5) LAT-386 represents the same bed as LAT 14 but was sampled where the unit appeared to contain more argillaceous material. D-34 Phosphate rock, argillaceous FSH - 15 D-33 Mudstone and phosphate rock FSH - 16 Mudstone FSH - 17 Phosphate rock, argillaceous FSH - 18 D-30 Mudstone FSH - 19 D-29 Mudstone ERC- 20 0-28 Mudstone LAT- 21 D-27 Mudstone, calcareous, fos. col. no. 48-KPM -37 LAT- 22 0-26 Mudstone LAT- 23 0-zs Mudstone, calcareous LAT- 24 Mudstone, calcareous ERC- 25 Mudstone ERC -387 (0.85) ERC-387 represents the same bed as ERC-25 but was sampled where the unit appeared to contain more argillaceous material. Mudstone, calcareous ERC - 26 D-22 Mudstone, calcareous ERC-27 Mudstone, calcareous ERC-28 0-20 Phosphate rock, argillaceous, fos. col. no. 48-KPM-36 LAT- 29 Phosphate rock LAT-30 Phosphate rock, argillaceous LAT-31 Phosphate rock and mudstone DAB-32 Phosphate rock and mudstone DAB-33 0-15 Phosphate rock and mudstone, fos. col. no. 48- KPM- 35 DAB- 34 D-14 Mudstone, phosphatic ERC- 35 Mudstone and phosphate rock ERC- 36 0-12 Phosphate rock and mudstone, fos. col. no. 48-KPM-34 ERC- 37 0-ti Phosphate rock DAB- 38 0-10 Phosphate rock and mudstone, fos. col. no. 48 -KPM -33 DAB- 39 D. 9 Mudstone DAB- 40 D- 8 Phosphate rock and mudstone DAB- 41 DAB- 42 / . 3 Phosphate rock, argillaceous 1)- 6 Mudstone and phosphate rock DAB- 43 1 Fossil collection made by K. P . McLaughlin, Paleontology and St rat igi aphy Branch, U. S. Geological Survey.

Bed Chemical anal ses rcent Cumulative ThiA...tness x Sample Thickness no. Rock description oss on ci thickness percent P205 no. (feet) P 0 Al 0 2 3 Fe2O3 ignition insoluble (feet) (cumulatilrei D" 5 Mudstone, phosphatic ERC- 44 D- 4 Mudstone ERC- 45 D- 3 Mudstone ERC- 46 Mudstone and phosphate rock DAB- 47 D" 1 Phosphate rock and mudstone, fos. col. no. 48-KPM-32 DAB- 48 C member of Phosphoria formation Sandstone, argillaceous Sandstone DAB- 49 ERC - 50 Sample of mudstone nodules within bed C-13 Sandstone, cherty, fos. col. no. 48-KPM-31 Chert and sandstone ERC-388 ERC- 51 ERC- 52 Z. 7 " Chert and sandstone Chert and sandstone Mudstone Mudstone, calcareous Mudstone, calcareous LAT- 53 LAT- 54 LAT-391 LAT-390 LAT-389 Lat-391, LAT-390, and LAT-389 represent three thin clay layers within bed C-9. ,- Limestone. argillaceous Sandstone and limestone, cherty Limestone, sandy Limestone, sandy, cherty Sandstone, cherty LAT- 55 ERC - 56 ERC- 57 ERC- 58 DAB- 59 Sandstone, cherty DAB-392 DAB-392 was a grab sample of less weathered rock in bed C-4. C- ? Mudstone and chert, fos. col. no. 48-KPM-30 Chert and sandstone Chert DAB- 60 DAB- 61 LAT- 62 B member of Phosphoria formation Mudstone, sandy Mudstone and phosphate rock Mudstone Mudstone, calcareous Mudstone RLP-393 RLP- 63 RLP-395 RLP-394 RLP- 64 Mudstone LAT- 65 ?O n

Mucistone, calcareous 1 LAT-396 (0.2) 1 0.4 LAT-396 represents a 0.2 foot layer containing quartz crystals in bed B-1. A member of Phosphoria formation A- 2 A - 1 Mudstone, calcareous Limestone, argillaceous; fos. col. nos. 48 -KPM -27 and 48 -KPM -28 DAB- 66 DAB- 67 Quadrant formation Cq-1 Sandstone DAB- 68 2.0 J 1

SPECTROGRAPHIC ANALYSES—SHEEP CREEK, MONTANA. LOT NO. 1234. Semi-quantitative analyses of samples of the Phosphoria formation, Sheep Creek, Montana (see immediately preceding pages for location of section, thickness and description of strata, and chemical analyses of samples), made by U. S. Bureau of Mines Laboratory, Albany, Oregon. In addition to the elements listed in the table below, Sb, As, Ba, Be, Bi, Cd, Ga, Ge, Au, In, Li, Hg, Pt, Ta, Sn, and W were looked for in all samples but were not detected. Explanation of symbols A more than 10 percent E 0.01-0.1 percent B 5-10 percent F 0.001-0.01 percent C 1-5 percent G less than 0.001 percent D 0.1-1 percent ND not detected Bed no. d-t Sample no. DAB- 80 Al B F Ca A Cr ND Co ND Cb ND Cu G Fe Pb ND Mg Mn E Mo F Ni F Si A Ag ND Na E Sr ND Ti E E Zn E Zr F ND ND ND G ND D E F F A ND E ND E E E E DAB- 79 no nnel nn onn F ND G B ND D E F F A ND E F E E ND E LAT- 78 F ND E ND G B ND D E F F A ND E F E E ND F LAT- 77 F ND CE ND G B ND D E F F A ND F F E E I ND F LAT- 76 ND E F D ND G ND D E F E AINDF ND E E E F ERC- 75 ND F E ND G ND D E F E A ND E ND E E E F ERC- 74 ND F E ND G ND D E F E A ND F ND E E E F ERC- 73 E ND F ND G ND D E F F A NDENDE E E F DAB- 72 E ND F ND D E F F A ND E ND E E E F G DAB- 71 E ND ND F ND D E F F A ND E ND E E E F DAB- 70 E ND ND G F G ND D E F F A ND E ND E E E F DAB- 69 E ND ND F ' -45 r0000 00,mm -c- t- 2m°mmmm m 4-312 11 ,TIv 11 ,0 °MX w m ,Wfv .-.0 u1,000.4 0, VI.O.WN .. . OW OOW W : ::

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Bed Sample no. Al B Ca Cr Co Cb Cu Fe Pb Mg Mn Mo Ni SI no. Ag Na Sr Ti Zn Zr LAT-390 FCEFEGANDCDFDAGEFDEDE LAT-389 LAT- 55 F E E E G A ND D F E A G E F D E E E F F A B F E ND ND ND ND G G ND ND A E E F F E E A A G ND E F F ND E E E E E E E F ERC- 56 GC1 CO UU U U UU UUU ERC- 57 F AENDNDGCNDBEFEAlsIDFNDEEEF ERC- 58 B E F E E ND ND G ND A ND F A F ND E E E F D E F DAB- 59 ND G ND F A E ND G E ND E E E F F B

DAB-392 F ND ND ND G ND D E F E A ND E ND E E E F D E F DAB- 60 F E ND ND G ND F A G E ND E E E F DAB- 61 F E ND ND G ND D E F F A G E ND E E E F FCFNDNDGBEEEF,EAGEFEEEE LAT- 62 B­ 6 13-s B­ 4 S-2 RLP-393 RLP- 63 RLP-395 RLP-394 RLP- 64 B F E F E G B E D F F E A F E F D E E E CF A E ND ND G D D E F E A F D F E E E E F D F F ND G B ND D E F E A G F F E E E E CFCEFNDGBNDCDFEAGEFEEEE CFDFNDIWGBNDDEFEAGEFEEDE B-1 LAT- 65 LAT-396 BEDF.FNDGBNDDEFEAGEFDEEE B F F F E G A ND D F E A G E F E E D E A­ 2 A-1 DAB- 66 DAB- 67 CF CF A A E E ND ND ND ND G G ND ND E E F F F F A A ND ND E E ND ND E E E E E E F F eq-1 DAB- 68 F E ND ND G ND D E F F A ND E ND E E F F 4-tY%

OIL SHALE ANALYSES -SHEEP CREEK, MONTANA. LOT NO. 1234. Oil shale analyses of samples of the D member of the Phosphoria formation, Sheep Creek, Montana (see immediately preceding pages for location of section, thickness and description of strata, and chemical analyses of samples), made by U. S. Bureau of Mines Petroleum and Oil-Shale Experiment Station, Laramie, Wyoming, by the modified Fischer-Retort method. None of the samples showed a tendency to coke. Bed no. Sample no. Oil Yield of products Wei ht (percent) Water Spent sha e Gas + loss Gallons per ton it Water Specific gravity 3f oil at 60*/60F. Properties of spent shale Percent of original shale oss on Ash ignition D-48 D-47 D-46 D-45 D-44 VEM1 VEM2 VEM- 3 VEM- 4 JES5 D-43 D-42 D-41 D-40 JES6 JES7 JES8 OAP9 OAP-385 D-39 D-38 D-37 D-36 D-35 OAP- 10 OAP- 11 OAP- 12 OAP- 13 LAT- 14 D-34 D-33 D-32 D-31 LAT-386 FSH- 15 FSH- 16 FSH- 17 FSH- 18 .11MM 4111.M. *9.8 D-30 D-29 D-28 D-27 D-26 FSH- 19 FSH- 20 ERC- 21 LAT- 22 LAT- 23 D-25 D-24 D-23 D-22 LAT- 24 ERC- 25 ERC -387 ERC- 26 ERC- 27 1 Estimated fY\

Bed no. Sample no. Yield of products lingjlIllLaal pent s le as + loss Gallons er ton Oil Water Specific gravity of oil at 60/60° F. Pro Properties of sp ent shale Percent of original shale Loss on Ash ignition D-21 D-20 D-19 D-18 D-17 ERC- 28 LAT- 29 LAT- 30 LAT- 31 DAB- 32 D-16 D-15 D-14 D-13 D-12 DAB- 33 DAB- 34 ERC- 3S ERC- 36 ERC- 37 S. 0 0,990 D-11 D-10 D- 9 D- 8 D- 7 DAB- 38 DAB- 39 DAB- 40 DAB- 41 DAB- 42 89. Z D- 6 D- S D- 4 D- 3 D- 2 DAB- 43 ERC- 44 ERC- 45 ERC- 46 DAB- 47 D- 1 DAB- 48 1 Estimated 3to

CEDAR CREEK, MONTANA. LOT NO. 1256. D member of Phosphoria formation sampled in bulldozer trench near Cedar Creek, sec. 26, T. 9 S., R. 11 W., Beaverhead County, Montana, on eastern limb of a syncline. Beds strike north and dip 61° W. Section measured by E. T. Ruppel nd sampled by J. A. Kelleher in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description Sample no. Thickness (feet) Chemical analyses ( rcent P205 insoluble Cumulative thickness (feet) Thickness x percent P (cumulative/ E member of Phosphoria formation-basal bed only EChert ETR-585 I 2.3 I 78.5 D member of Phosphoria formation-base not exposed D-43 Mudstone ETR- 584 D-42 Mudstone ETR-583 D-41 D-40 D- 3c Phosphate rock, cherty, calcareous Limestone, phosphatic, argillaceous Mudstone ETR-582 ETA- 581 ETR-580 D- .V., D-37 D-36 D-35 Mudstone, calcareous, phosphatic

Mudstone Mudstone and calcareous phosphate rock Mudstone, calcareous and phosphate rock Limestone ETR-579 ETR-578 ETR-577 ETR- 576 ETR-575 J-33 Mudstone, calcareous Phosphate rock, calcareous Phosphate rock, calcareous Mudstone Phosphate rock, argillaceous ETR- 574 ETR-573 ETR-572 ETR- 571 ETR- 570 I -2? Phosphate rock; fos. col. no. 48-KPM -481 Phosphate rock, argillaceous Mudstone Phosphate rock, argillaceous Phosphate rock, argillaceous E TR-569 ETR- 568 ETR-567 ETR- 566 ETR-565 0. 7? Phosphate rock, argillaceous Limestone, argillaceous Mudstone, calcareous, phosphatic Mudstone, phosphatic Phosphate rock and calcareous mudatone; fos. col. no. 48-KPM-47 ETR-564 ETR- 563 ETR- 562 ETR-561 ETR - 560 Phosphate rock, argillaceous ETR- 559 1 Fossil collection made by K. P. McLaughlin, Paleontology and Stratigraphy Branch, U. S. Geological Survey.

Chemical analyses

Cumulative Thickness x Bed Sample Thickness ercent Rock description. thickness no. no. (feet) (feet) percent P (cumulative) P205 insoluble D-17 Phosphate rock, argillaceous. and calcareous mudstone ETR- 558 D -16 Mudstone, phosphatic ETR-557 D-15 Mudstone, calcareous ETR-556 D-14 Phosphate rock, calcareous; fos. col. no. 48 -KPM -46 ETR - 555 D-13 Mudstone, phosphatic ETR-554 D-12 Mudstone, phosphatic ETR-553 D-11 Phosphate rock and limestone ETR- 552 D-10 Phosphate rock, calcareous ETR- 551 D- 9 Mudstone, phosphatic ETR- 550 D- 8 Phosphate rock, argillaceous ETR-549 D- 7 Phosphate rock, argillaceous ETR-548 .2. ; . 5 D- 6 Mudstone, calcareous ETR- 547 D- 5 Mudstone ETR- 546 D- 4 Mudstone. calcareous ETR-545 D- 3 Phosphate rock and mudstone ETR-544 D- 2 Mudstone, phosphatic ETR-543 D- 1 Phosphate rock, sandy; fos. col. no. 48- KPM-44 ETR- 54 2 Stratigraphic interval of 286 feet between D-1 and approximate base of C member, includes few exposures of chert and limestone or dolomite. Stratigraphic interval of 123 feet between approximate base of C member and approximate top of Quadrant sandstone, strata concealed.

fr SA WTOOTH PEAK, MONTANA. LOT NO. 1241. C and E members and part of A member of Phosphoria formation measured in natural exposures, and B and D members sampled from hand trenches on Sawtooth Peak, NEISWI sec. 10, T. 12 S., R. 5 W., Beaverhead County, Montana, on overturned east limb of Snowcrest anticline. Beds at top of section strike N. 5 W. and dip 75* W. Beds at base of section strike N. 40' E. and dip 64' SE. Section measured by F. S. Honkala and 0. A. Payne and sampled by Payne in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness x Bed Sample Thickness rcent Rock description thickness P0 no. no. (feet) ci (feet) (cumulative P2°5 insoluble Dinwoody formation 1td-2 Not described; fos. col. no. 48-KPM-771 ?d-1 Mudstone, quartzitic E member of Phosphoria formation E-15 Quartzite E-14 Sandstone E-13 Quartzite E-12 Quartzite E-11 Sandstone E -10 Sandstone E- 9 Sandstone E- 8 Quartzite EQuartzite E- 6 Quartzite E- S Sandstone, quartzitic 5/.7 E- 4 Quartzite E- 3 Sandstone, quartzitic E- 2 Sandstone, quartzitic E- 1 Conglomerate and quartzite D member of Phosphoria formation D-14 Phosphate rock and quartzite FSH-438 D-13 Phosphate rock and mudstone FSH-437 D-12 Mudstone FSH-436 D-11 Phosphate rock and mudstone FSH-435 D-10 Mudstone, phosphatic, calcareous FSH-434 D- 9 Mudstone and phosphate rock, argillaceous, calcareous FSH-433 1 Fossil collection made by K. P. McLaughlin, Paleontology and Stratigraphy Branch, U. S. Geological Survey, from bed 16.3 feet above base of formation.

Chemical analyses Cumulative Thickness z Bed Sample Thickness (ercent Rock description thickness; no. (feet) no. (feet) percent P (cumulative, P2O5 insoluble D- 8 D- 7 D- 6 D- 5 D- 4 Phosphate rock and mudstone Limestone; fos. col. no. 48-KPM-76 Mudstone Mudstone Mudstone FSH-432 FSH-431 FSH-430 FSH-429 FSH-428 D- 3 D- 2 D- 1 Mudstone Mudstone Mudstone FSH-427 FSH-426 FSH-425 C member of Phosphoria formation Chert Sandstone Sandstone Sandstone Sandstone FSH-424

Sandstone, quartzitic Quartzite Chert and mudstone Conglomerate, cherty Chert

-5, Covered interval, float strongly suggests limestone Limestone Limestone Limestone Limestone

Limestone Limestone Limestone Limestone; fos. col. no. 48-KPM - 75 Limestone -"

Limestone Limestone Limestone and dolomite Chert Dolomite - -

-

Dolomite Dolomite

C-34 Dolomite C-33 Limestone; fos. col. no. 48-KPM -74 C-32 Limestone and chert C-31 Limestone and chert C-30 Limestone and chert C-29 Limestone C-28 Limestone C-27 Limestone C -26 Limestone C-25 Limestone C-24 Limestone WOO C-23 Limestone, sandy C-22 Limestone, sandy C-21 Limestone, dolomitic, sandy? C-20 Chert 175. ) C-19 Sandstone, calcareous C-18 Chert, sandy, calcareous C-17 Chert, sandy C-16 Chert, sandy C -15 Chert, sandy C-14 Chert, sandy C-13 Chert, sandy C-12 Chert, sandy C-11 Chert, sandy C-10 Chert, sandy C- 9 Chert C- 8 Chert CSandstone and chert C- 6 Chert C- 5 Chert C- 4 Chert C- 3 Chert C- 2 Chert C- 1 Chert, a rgillaceous B member of Phosphoria formation B- 6 Mudstone and phosphate rock FSH-423 B- 5 Mudstone and phosphate rock FSH-422 FSH-421 B- 4 Mudstone FSH-420 B- 3 Phosphate rock B- 2 Limestone, phosphatic, sandy: fos. col. FSH-419 B- 1 Phosphate rock, sandy; tos. col. no. no. 48-KPM -73 FSH-418 48-KPM-72

Bed no. Rock description Sample no. Thickness (feet) 1 Chemical analyses I f (percent) Acid Pa05 insoluble Cumulative thickness (feet) Thickness x percent P2O5 (cumulative; A member of Phosphnria formation-base not exposed A-16 Chert A-15 Dolomite, argillaceous; fos. col. no. 48-KPH-71 A -14 Mudstone and sandstone, calcareous A-13 Sandstone, calcareous, argillaceous A-12 Sandstone, calcareous, argillaceous A-11 Sandstone, calcareous A-10 Sandstone, calcareous A- 9 Sandstone, calcareous A- 8 Sandstone, calcareous A- 7 Sandstone, calcareous, argillaceous A- 6 Dolomite, argillaceous A- 5 Dolomite, argillaceous A- 4 Dolomite, sandy A- 3 Dolomite, sandy A- 2 Dolomite, sandy A- 1 Dolomite, sandy S. 0 S. 0

HIDDEN PASTURE CREEK, MUDDY CREEK, AND BIG SHEEP CANYON, MONTANA. LOT NOS. 1224, 1225, 1226 and 1227. Phosphoria formation sampled in hand trenches and natural exposures on east limb of Dixon Mountain syncline; D and E members, lot no. 1224, sampled in NEISWI sec. 26; B and C members, lot no. 1225, in SEISW-1 sec. 35: and upper part of A member, lot no. 1226, in NEiNWtsec. 35, T. 13 S., R. 10 W.; lower part of A member, lot no. 1227, sampled in NWINWi sec. 11, T. 14 S., R. 10 W., Beaverhead County, Montana. Beds strike northwest and dip 30-40° SW. Section measured by W. R. Lowell and sampled by D. A. Bostwick, E. T. Ruppel, and R. L. Parker in August 1947. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed Chemical anal ses ercent Cumulative Thickness x Sample Thickness Rock description oss on , Aci thickness percent P295 no. no. (feet) Fe2O F P205 A1203 ignition insoluble (feet) (cumulative, Dinwoody formation-not measured E member of Phosphoria formation, lot no. 1224 E-34 Mudstone ZS. 0 E-33 Mudstone, cherty WRL-222-47 E-32 Mudstone, cherty WRL-221-47 E- 31 Mudstone, cherty WRL-220-47 E- 30 Mudstone, cherty WRL-219-47 E- ,,,-29 Mudstone, cherty WRL-218-47

n 28 Mudstone, calcareous WRL-2 .17-47 E -27 Mudstone, calcareous WRL-216-47 E- 26 Quartzite WRL-215-47 38, 7.6 E-25 Chert WRL-214-47

-23 Chert and mudstone WRL-212-47 Chert WRL-211-47 "24 Chert WRL-213-47 21 Chert WRL-210-47

-20 Chert WRL-209-47 -19 Limestone WRL-208-47 Chert WRL-207-47 MID .,. Chert WRL-206-47

Chert WRL-205-47 s Limestone WRL-204-47 Chert WRL-203-47 Mb OM -13 Chert WRL-202-47 '12 Chert WRL-201-47

1Chert and limestone WRL-200-47 Chert WRL-199-47 Mk ..

- 9 Mudstone WRL-107-47 8 Chert WRL-106-47 - 7 Mudstone WRL-105-47 - ° Mudstone WRL-104-47 Mudstone WRL-103-47

Chemical anal ses Bed Sample Thickness Cumulative Thickness x Rock description Loss on no. no. (feet) P205 A1203 Fe2O3 V205 F Aci thickness percent P205 ignition insoluble (feet) (cumulative, F:L," 4 Mudstone WRL-102-47 L.,' 3 Mudstone WRL-101-47 ' L,- 2 Mudstone WRL-100-47 ' / Mudstone WRL- 99-47 D member of Phosphoria formation, lot no. 1224 Mudstone Mudstone Mudstone Limestone, argillaceous Limestone WRL- 98-47 WRL- 97-47 WRL- 96-47 ViRL- 95-47 WRL- 94-47

SO. 3 '-46 Limestone, argillaceous Limestone, argillaceous Phosphate rock Mudstone, calcareous and phosphate rock Phosphate rock, calcareous WRL- 93-47 WRL- 92-47 WHL- 91-47 WRL- 90-47 WRL- 89-47

'-41 Mudstone Phosphate rock, calcareous, argillaceous Phosphate rock and argillaceous limestone Limestone, phosphatic, argillaceous Dolomite, argillaceous WRL- 88-47 WRL- 87-47 WRL- 86-47 WRL- 85-47 WRL- 84-47

-

, ,. -,1 3 ''32 .,. -'v Phosphate rock, argillaceous, calcareous Limestone, argillaceous Phosphate rock, argillaceous and limestone Limestone, argillaceous Mudstone, calcareous, phosphatic Limestone and phosphate rock Mudstone, calcareous, phosphatic Limestone Mudstone, calcareous, phosphatic Limestone WRL- 83-47 WRL- 82-47 WRL- 81-47 WRL- 80-47 WRL- 79-47 WRL- 78-47 WRL- 77-47 WRL- 76-47 WRL- 75-47 WRL- 74-47

-a

0-2o D-18 0­16 Mudstone, calcareous Phosphate rock, argillaceous, calcareous Mudstone, phosphatic, calcareous Mudstone, calcareous Mudstone, phosphatic, calcareous Mudstone Mudstone and phosphate rock Phosphate rock, argillaceous, calcareous Mudstone Mudstone, phosphatic WRL- 71-47 WRL- 70-47 WRL- 69-47 WRL- 68-47 WRL- 67-47 WRL- 66-47 WRL- 65-47 WRL- 64-47 WRL- 63-47 WRL- 62-47 /2-14 u-13 0­10 Mudstone, phosphatic Phosphate rock Mudstone, calcareous Phosphate rock, argillaceous, calcareous Mudstone WRL- 61-47 WRL- 60-47 WRL- 59-47 WRL- 58-47 WRL- 57-47 D. 9 *D. 8 D. s Mudstone, calcareous, phosphatic Phosphate rock, argillaceous, calcareous Phosphate rock, calcareous, argillaceous Limestone Phosphate rock, argillaceous, calcareous WRL- 56-47 WRL- 55-47 WRL- 54-47 WRL- 53-47 WRL- 52-47 O- 1 Phosphate rock, argillaceous, calcareous Mudstone, phosphatic, calcareous Limestone Mudstone, calcareous, phosphatic WRL- 51-47 WRL- SO-47 WRL- 49-47 WRL- 48-47 C member of Phosphoric formation. lot no. 1224 -top bed only 111.110 cSandstone, phosphatic WRL - 47-47 (1.7) WRL-47-47, lot no. :424, logged as equivalent to upper 1. 7 feet of WRL-198-47, lot no. 1225. C member of Phosphoria formation, lot no. 1225 Limestone, sandy WRL-198-47 Sandstone, calcareous WRL-197-47 Chert, calcareous WRL-196-47 Chert, calcareous WRL-195-47

Bed no. Rock description Sample no. Thickness (feet) P2 5 Chemical anal ses percent oss on Al A103 Fe Fe0 2O3 V0 F ignition insoluble Cumulative thickness (feet) Thickness x percent P 05 (c ulatiirej C­30 Chert and limestone Chert and limestone Mudstone, calcareous Limestone, cherty Limestone, sandy WRL-194-47 WRL-193-47 WRL-192-47 WRL-191-47 WRL- 190-47 v-Z4 C'-23 Sandstone, calcareous Limestone, sandy Sandstone and limestone Limestone, sandy Limestone, sandy WRL-189-47 WRL-188-47 WRL-187-47 WRL- 186-47 WRL-185-47 ,C -22 Co ,,C-/9 '-18 Sandstone, calcareous Limestone, sandy Limestone, cherty Chert, calcareous Limestone, sandy WRL-1844 7 WRL- 183-47 WRL-182-47 WRL- 181-47 WRL-180-47 , 7 ,.% -16 ;4 -15 Limestone, sandy Sandstone and Limestone Limestone, sandy Sandstone, calcareous Limestone WRL- 179-47 WRL-178-47 WRL-1.77-47 WRL-176-47 WRL-175-47 O. Z C - b 0 Limestone Sandstone, calcareous Chert, sandy Chen Chert WRL-174-47 WRL-173-47 WRL-172-47 WRL-171-47 WRL-170-47 Cr.. - 7 re " 4 Chert Chert Chert chert Chert WRL- 169-47 WRL-168-47 WRL-167-47 WRL- 166-47 WRL-165-47 Chert, calcareous Chert WRL-164-47 WRL-163-47 B member of Phosphoria formation, lot no. 1225 Mudstone and chert Mudstone Limestone. argillaceous WRL-162-47 WRL-161-47 WRL-160-47 0.("3 0. (.2 4 (4,

B-27 Limestone, argillaceous and phosphate rock B-26 Mudstone B-25 Mudstone, phosphatic, calcareous B-24 Chert and mudstone B-23 Mudstone, cherty WRL-159 -47 WRL - 158 -47 WRL-157-47 WRL-156-47 WRL-155-47 15. SO 8-22 Mudstone, cherty B-21 Chert 8-20 Cheri, calcareous and mudstone 8-19 Phosphate rock, calcareous, argillaceous B-18 Mudstone WRL-154-47 WRL-153-47 WRL-152-47 WRL-151-47 WRL-150-47 Z. 3 B-15 Limestone, argillaceous Mudstone, calcareous, phosphatic Mudstone, calcareous Mudstone, phosphatic Mudstone, calcareous WRL-149-47 WRL-148-47 WRL -147-47 WRL-146-47 WRL -145-47 Z. 7 O. 03 a-lo Limestone, argillaceous Phosphate rock, calcareous Limestone, argillaceous Limestone, argillaceous Limestone, argillaceous WRL-144-47 WRL-143-47 WRL-142-47 WRL-141-47 WRL-140-47 6;0 O. 1 B- 7 Limestone, phosphatic, argillaceous Mudstone, calcareous and calcareous phosphate rock Phosphate rock, calcareous Phosphate rock, calcareous and calcareous mudstone Limestone, argillaceous WRL-139-47 WRL-138-47 WRL-137-47 WRL-136-47 WRL-135-47 207,68 h. z 11Phosphate rock Phosphate rock WRL-134-47 WRL-133-47 0.008 3. 16 A member of Phosphoria formation, lot nos. 1226 and 1227 Lot no. 1226 -!3 '2 -Si - '0 Limestone Mudstone, calcareous Limestone Limestone Mudstone, calcareous WRL-132-47 WRL-131-47 WRL-130-47 WRL-129-47 WRL-128-47

A -48 A -47 Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous WRL-127-47 WRL-126-47 WRL-125-47 S. o -­ 1 See additional analyses at end of table.

A Bed no Rock description mpl no hic tress feet 11111 hemic 1 &nal A120 Fe2O3 v2°5 kig! MMI oss on ignition insolub umulativ thickness (feet Thickness x rcent P 0 (cumulative A-45 A-44 A-43 A-42 A-41 Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous WRL-124 - 7 WRL-123-47 WRL-122-47 WRL-121-47 WRL-120-4' 0.0.1.1._

A-40 A'39 '38 A. -37 A-36 Mudstone, calcareous Sandstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous WRL-119-47 WRL-118-47 WRL-117-47 WRL-116-47 WRL-115-47

:0 2 !".35 7-34, ;-32 '1-31 Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous Mudstone, calcareous and calcareous sandstone WRL-114-47 WRL-113-47 WRL-112-471 WRL-111-47 WRL -110-47 :5.2 1;-30 '1-29 A-28 Mudstone, calcareous Sandstone, calcareous an mudatone Limestone, cherty Limestone and sandstone Phosphate rock WRL-109-47 WRL-108-47 WRL-250-47 WRL-249-47 WRL -248-47 2 A.24 A `'.23 Limestone, cherty Limestone and chert Limestone WRL-247-47 WRL-246-47 WRL-245-47 Lot no. 1227 A-21 A-2n A q.-113 Limestone, sandy Limestone and sandstone, calcareous Limestone, sandy Limestone Chert and limestone V.114A121.11ZIO WRL-243- " RL-242-47 RL-241-47 L'It L-240-47 DIE !Mir 4'. MEE AA -/ 7 A. , 16 i , A -,`11 Limestone Limestone, argillaceous Limestone, argillaceous Muds tone Sandstone WRL-239 WRL-238-47 WRL-237-47 WRL-236-47 RL-235-47 O.. A412. A:1 -1'13 Limestone, sandy, cherty Sandstone, calcareous Mudstone, calcareous WRL-23 - WRL-233-47 WRL-232-47

SiO2 A- 9 Limestone, argillaceous WRL-231-47 A- 8 Chert and limestone float, bedrock not exposed A- 7 Chert, calcareous, sandy WRL-229-47 0. 54* A- 6 Chert and limestone WRL-228-47 A- 5 Chert, calcareous, and limestone WRL-227-47 A- 4 Sandstone, calcareous WRL-226-47 A- 3 Limestone, cherty, sandy WRL-225-47 A- z Limestone WRL-224-47 A- 1 Limestone WRL-223-47 56.98** Quadrant formation-not measured Cumulative data incomplete due to missing information. Computations start from zero after interruption. Note incompleteness of cumulative data. Additional analyses of sample WRL-150-472 Sample DO . P205 F SiO2 TiO2 CaO MgO Na2O K20 MnO WRL - 150-47 ' 0.31 Ni Cr2O3 Co Zn Cu Pb Ag 11°03 W Organic matter 3 Analyses made by the U. S. Geological Survey, Geochemistry and Petrology Branch. CO2 atui S reported present.

WADHAM SPRINGS, MONTANA. LOT NOS. 1246 and 1247. Phosphoria formation sampled in bulldozer trenches near Wa. am prings on sout east limb of anticline. Upper part of formation, lot no. 1246, sampled in north trench, SEISW1 sec. 22; and lower part of formation, lot no. 1247, in south trench, SWINE.; sec. 28. T. 13 S., R. 7 W., Beaverhead County, Montana. Beds strike N. 30° E. and dip 70-80' SE. Section measured by D. A. Bostwick, E. R. Creasman, and L. A. Thomas and sampled by Bostwick, Cressman, Thomas, and W. H. Wilson in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness x Bed Sample Thickness (percent Roc k description thickness percent P,O, no. no. (feet) ci (feet) (cumulatrire I P205 insoluble Dinwoody formation

It'd- t Mudstone ERC-157 E member of Phosphoria formation, lot no. 1247 E -12 Mudstone and chert ERC- 156 E-11 Siltstone and sandstone ERC-155 E-10 Mudstone, chert, and sandstone DAB-154 E- 9 Mudstone and chert DAB-153 E- 8

DAR-152 Sandstone and chert E- 7 Muciston, and chert ERC -151 E- 6 Chert ERC-150 E- 5 ERC-149 Mudstone and chert E- 4 Mudstone and chert; fps. col. no. 48- KPM -69i DAB-148 E- 3 Mudstone and chert DAB-147 E- 2 Mudstone and chert; fos. col. no. 48-KPM-69 DAB-146 S- 1 Chert, phosphatic ERC-145

of Phoshoria formation lot no. 1247 D-23 Mudstone , phosphatic ERC-144 D-22 Phosphate rock, argillaceous ERC-143 Phosphate rock, argillaceous DAB-142 1' -20 Mudstone, phosphatic DAB-141 Mudstone; fos. col. no. 48-KPM-68 DAB-140 "-18 Mudstone and phosphate rock ERC -139 Mudstone ERC-138 Mudstone and phosphate rock ERC- 137 I -15 Mudstone DAB-136 -14 Mudstone, phosphatic DAB-135 -13 Phosphate rock, argillaceous DAB-134 -12 Mudstone, phosphatic DAB-133

D-11 Mudstone and phosphate rock DAB-132 D-10 Mudstone DAB-131 D- 9 Mudstone ERC-130 D- 8 Mudstone, phosphatic ERC -129 D- 7 Mudstone ERC- 128 D- 6 Mudstone and phosphate rock ERC - 127 332.3/ D- 5 Mudstone ERC -126 D- 4 Mudstone, phosphatic ERC -125 D- 3 Phosphate rock, argillaceous DAB-124 D- 2 Mudstone and phosphate rock DAB-123 D1 Mudstone and phosphate rock DAB-122 29 feet below D-1 not exposed though trenched by bulldozer and hand to depth of 24 feet. Interval probably chiefly D member. C member of Phosphoria formation, lot nos. 1246 and 1247 Lot no. 1247 C-18 Limestone; fos. col. no. 48 -KPM-67 ERC-121 ('-17 Limestone; fos. col. no. 48-KPM-66 DAB-120 C-16 Limestone; fos. col. no. 48 -KPM -65 DAB-119 C- IS Limestone; fos. col. no. 48- KPM -64 DAB-118 C-14 Mudstone, calcareous ERC-117 C-13 Mudstone, calcareous

ERC -116 C-12 Mudstone, calcareous ERC-115 Limestone DAB-114 Z. 6 C-10 Limestone; fos. col. no. 48-KPM -63 DAB-113 DAB-112 Limestone; fos. col. no. 48-KPM -62 C- 8 Limestone DAB-111 Limestone DAB-1 !O C- 6 Limestone DAB1 9 C- 5 Limestone, argillaceous DAB-108 Sandstone, calcareous DAB-107 C- 3 Chert DAB-106 Lot no. 1246 C- 2 Chert, sandstone and mudstone LAT-105 C- 1 Mudstone and chert DAB-104 B member of Phosphoria formation, lot no. 1246 13- 8 Mudstone; fos. col. nos. 48-KPM-61 and Mudstone, phosphatic LAT-264 (1.3) 48-KPM -60 DAB-103 LAT-264 re resents u r 1.3 feet of DAB-103. 1 Fossil collection by K. P. McLaughlin. Paleontology and Stratigraphy Branch, U. S. Geological Survey.

Chemical analyses Cumulative Thickness x Bed Sample Thickness (percent Rock description thickness percent P,05 no. no. (feet) ca (feet) (cumulattirei P205 insoluble B- 7 Chert and mudstone DAB-102 B- 6 Mudstone and chert ERC-101 B- 5 Mudstone, cherty ERC-I00 B- 4 Phosphate rock, sandy ERC- 99 B- 3 Mudstone; fos. col. no. 48-KPM-59 LAT- 98 B- 2 Phosphate rock, argillaceous LAT-263 B- 1 Phosphate rock, argillaceous LAT-26Z A member of Phosphoria formation, lot no. 1246 A-15 Mudstone, calcareous LAT- 96 A-14 Mudstone and limestone ERC- 95 A-13 Limestone ERC- 94 A-12 Mudstone, calcareous ERC- 93 A-11 Limestone DAB- 92 0. Z A-10 Mudstone, calcareous DAB- 91 A- 9 Limestone; fos. col. no. 48-KPM-58 DAB- 90 A- 8 Mudstone, calcareous

LAT- 89 A- 7 Mudstone, calcareous LAT- 88 A- 6 Mudstone, calcareous LAT- 87 A- 5 Mudstone, calcareous, cherty ERC- 86 A- 4 Mudstone and limestone ERC- 85 A- 3 Mudstone and chert; fos. col. no. 48-KPM-57 ERC- 84 A- 2 Limestone DAB- 83 A- 1 Mudstone, calcareous and sandstone DAB- 82 Quadrant formation Cq -1 Sandstone DAB- 81 cZ,

CENTENNIAL RANGE TRENCH NO. 4, MONTANA. LOT NO. 1251. B member of Phosphoria formation sampled in hand trench at Centennial Range locality no. 4 along south side of east fork of Odell Creek, near Et corner sec. 6, T. 15 S.. R. 1 W., Beaverhead County, Montana, on southward-dipping homocline. Beds strike N. 70° W. and dip 10' S. Section measured by F. S. Honksla and sampled by 0. A. Payne in August 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. m oChemical anal ses - rcent Cumulative Thickness z Sample Thickness Rock description oss on ci thickness percent P no. (feet) F 0 F 3 Fe2O3 ignition insoluble C member of Phosphoria formation—not measured B member of Phosphoria formation (feet) (cumulative, A member of Phosphoria formation—not measured No.

Limestone ODELL CREEK, MONTANA. LOT NO. 1252. Upper part of Phosphoria formation sampled and lower part of Dinwoody formation measured in hand trench on west side of Odell Creek, SE; sec. 1, T. 15 S., R. 2 W., Beaverhead County, Montana, on southward-dipping homocline. Beds strike N. 82° E. and dip 30° S. Section measured by F. S. Honkala and 0. A. Payne and sampled by Payne and J. A. Kelleher in 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Bed no. Rock description Sample no. Thickness (feet) Chemical analyses

P2 05 i insoluble Cumulative thickness (feet) Thickness x percent P (cuinulat.rvej Lower part of Dinwoody formation ItA-29 ltA-28 ?d-2T ltA-26 Limestone Limestone Mudstone Limestone Limestone and dolomite

ItA-25 Itd-24 "11A-23 ltd-22 TA-21 Limestone Mudstone, calcareous Limestone and calcareous mudstone Dolomite

Dolomite and calcareous mudstone

Z. 7

,

IN-20 d-19 d-18 d-16 Dolomite Dolomite Dolomite Dolomite and calcareous mudstone Dolomite

d-14 d-13 Limestone Dolomite and limestone Mudstone and dolomite Dolomite and mudstone Dolomite

,

d-10 d- 9 d- 8 d- 7 d- 6 Dolomite Dolomite Dolomite and mudstone Dolomite Dolomite

Op ...

d- 5 d- 4 d- 3 2 d- 1 Dolomite and mudstone Mudstone, calcareous Mudstone Mudstone Mudstone, calcareous and dolomite

Fsh-417

E member of Phosphoria formation-upper part only E -16 E-15 E-14 E -13 E-12 Mudstone, calcareous Mudstone, calcareous and limestone Limestone, argillaceous Limestone Mudstone, calcareous FSH -416 FSH -415 FSH -414 FSH -413 FSH -412 Z. 18 E-11 E -10 E- 9 E- 8 E- 7 Limestone Limestone, argillaceous Limestone, argillaceous Mudstone, calcareous Mudstone FSH -411 FSH -410 FSH -409 FSH -408 FSH -407 E- 6 E- 5 E- 4 E- 3 E- 2 Chert Mudstone Chert Muristone and sandstone FSH -406 OAP-405 OAP-404 OAP-403 OAP-402 E- 1 OAP-401

CENTENNIAL RANGE TRENCH NO. 1, MONTANA. LOT NO, 1253. D, E, and part of C members of Phosphoria formation sampled in hand trench at Centennial Range locality no. 1 near crest of range, NW corner sec. 33, T. 14 S., R. 1 W., Beaverhead County, Montana, on southward-dipping homocline. Beds strike east and dip 200 S. Section measured by F. S. Honkala and 0. A. Payne and sampled by J. A. Kelleher in July 1948. Samples analyzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness x Bed Sample Thickness ( ercent thickness percent no. Rock description no. (feet) P205 (feet) (cumulative) PZ°5 insoluble Dinwoody formation E member of Phosphoria formation E-21 OAP-495 Mudstone, calcareous E-20 Mudstone, calcareous OAP-494 E-19 Mudstone, calcareous OAP-493 E-18 Mudstone, calcareous OAP-492 E-17 Chert OAP-491 E-16 Chert OAP-490 E-15 Chert OAP-489 E-14 Chert OAP-488 E-13 Chert OAP-487 E -12 Chert FSH -486 E-11 Chert FSH -485 E-10 Chert FSH -484 E- 9 Chert FSH -483 E- 8 Chert FSH -482 E- 7 FSH -481 Dolomite and calcareous mudstone E- 6 Chert FSH -480 E- 5 Chert FSH -479 E- 4 Chert, calcareous and mudstone FSH -478 76. Z E- 3 Mudstone and limestone FSH -477 E- 2 Mudstone and chert FSH -476 FSH -475 Mudstone, calcareous and chert D member of Phosphoria formation Mudstone OAP-474 Mudstone OAP-473 6 -19 Mudstone OAP-472 OAP-471 " 9 Mudstone Beds D-9 through D-12 are slumped and thicknesses may not be correct.

D- 8 D- 7 D- 6 D- 5 D- 4 Mudstone Mudstone, calcareous Mudstone Phosphate rock Mudstone OAP-470 OAP-469 OAP-468 OAP-467 OAP-466 D- 3 D- 2 D1 Mudstone, phosphatic Phosphate rock Mudstone OAP-465 OAP-464 OAP-463 C member of Phosphoria formation 1"V f r$ f..1 . 0 Os tcrr-.4) ArlvelNI t ' O U U O U U U QU O L) U U LW U Sandstone FSH -462 Sandstone FSH -461 Sandstone FSH -460 Sandstone FSH -459 Sandstone FSH -458 Sandstone FSH -457 Sandstone FSH -456 Sandstone FSH -455 Sandstone FSH -454 Chert FSH -453 Quartzite FSH -452 Dolomite, argillaceous

FSH -451 Limestone, sandy FSH -450 Limestone FSH -449 Dolomite and calcareous sandstone FSH -448 It is doubtful that the full thickness of the C member was exposed at this locality.

: CENTENNIAL RANGE TR CHES NOS. 2 AND 3, MONTANA-IDAHO. LOT NOS. 1254 AND 1255. Phosphoria formation sampled in Centen. 1 Range hand trenches nos. 2 and 3. Upper part of formation, lot no. 1255, sampled in trench no. 2, NW* sec. 12, T. 14 N., R. 40 E., Cl k County, Idaho. Beds strike N. 65' W. and dip 14° SW. Lower part of formation, lot no. 1254, sampled in trench no. 3, near NI come Aec. 2, T. 15 S., R. 1 W., Beaverhead County, Montana, at crest of range on southward-dipping homocline. Beds strike N. 70° W. artt'diy 22° S. Section measured by F. S. Honkala and 0. A. Payne and sampled by J. A. Kelleher and R. L. Konizeski in July 1948. Samples a-- 1,yzed by U. S. Bureau of Mines Laboratory, Albany, Oregon. Chemical analyses Cumulative Thickness ic Bed Sample Thies rcent Rock description thickness percent P,05 no. no. (feet)' (feet) (cumulatiVei P205 insoluble Dinwoody formation 11.d-2 itd-1 FSH -540 E member of Phosphoria formation, lot no. 1255 FSH -538 E-12 Mudstone, sandy FS-539 E-11 Mudatone E-10 Mudstone, sandy, calcareous FSH -537 E- 9 Mudstone and chert FSH -536 1116075:60550 E- 8 Chert FSH -535 E- 7 Chert, argillaceous FSH -534 E- 6 Chert, argillaceous FSH -533 E- 5 Chert, argillaceous FSH -532 E- 4 Chert, argillaceous FSH -531 E- 3 Chert and mudstone FSH -530 E- 2 Mudstone FSH -529 E1 Mudstone FSH -528 D member of Phosphoria formation, lot no. 1255 D-12 Mudstone OAP-527 D-11 Mudstone OAP-526 D-10 Mudstone OAP-525 Possible fault at top of D-9 indicated by gouge and breccia zone. No displacement apparent. Mudstone OAP-524 Mudstone OAP-523 OAP- 522 Mudstone, calcareous Phosphate rock OAP- 521 Mudstone OAP- 520 1)- 4 Mudstone, calcareous and phosphate rock OAP-519 D- 3 Phosphate rock OAP- 518

D- 2 Mudstone OAP-517 1.7 / D- 1 Phosphate rock, argillaceous OAP-516 C member of Phosphoria formation, lot nos. 1255 and 1254 Lot no. 1255 C-10 Sandstone FSH -515 Sandstone Sandstone, calcareous Sandstone FSH -514 FSH -513 FSH -512 C- 6 Sandstone FSH -511 C- 5 Sandstone FSH -510 C- 4 Sandstone FSH -509 C- 3 Sandstone, phosphatic FSH -508 C- 2 Sandstone, calcareous FSH -507 There is probably a gap of 10 feet or more between the lowest bed of lot no. 1255 and the highest bed of lot no. 1254. Lot no. 1254 C- 1 Chert OAP-541 0.4* B member of Phosphoria formation, lot no. 1254 B- 2 Phosphate rock, argillaceous OAP-5061 B- 1 Phosphate rock OAP-505 A member of Phosphoria formation, lot no. 1254 A- 7 Limestone and conglomerate OAP-504 A- 6 Limestone, argillaceous OAP-503 A- 5 Limestone, sandy and calcareous sandstone , FSH -502 A- 4 Sandstone, calcareous FSH -501 A- 3 Limestone, sandy, and calcareous sandstone FSH -500 A- 2 Sandstone, calcareous FSH -499 A" 1 Conglomerate, calcareous FSH -498 Quadrant formation Cq-1 Sandstone, calcareous FSH -497 Cumulative data incomplete due to missing information. See additional analyses at end of table.

Na matter Additional analyses of sample OAP-5052 Bed no. B-1 Sample no. OAP-505 P205 F Si ° TiO2 CaOMgO Na2O0 K 0 MnO IMO Cr2O3 Co Zn Cu Pb Ag MoO3 O. 002 matter 3 Analyses made by the U. S. Geological Survey, Geochemistry and Petrology Branch. Co2 and S reported present.