DEPARTMENT OF THE INTERIOR

FRANKLIN K. LANE, Secretary

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Director 

Bulletin 680

A GEOLOGIC RECONNAISSANCE FOR PHOSPHATE

AND COAL IN SOUTHEASTERN IDAHO

AND WESTERN WYOMING

BY

ALFRED REGINALD SCHULTZ

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1918
in

0

Q
CONTENTS.

Page

Introduction.............................................................. 7

Purpose of investigation............................................... 7

Earlier work.......................................................... 9

Geography................................................................. 10

Itinerary.............................................................. 10

Topography and settlement............................................. 1.1

Geology.................................................................. 12

Stratigraphy.......................................................... 12

General section.................................................... 12

Pre-Cambrian to Carboniferous (Pennsylvanian series, inclusive).... 16

General features............................................... 16

Pre-Cambrian rocks............................................ 17

Cambrian system.........;..................................... 17

Flathead quartzite........................................ 18

Gros Ventre formation..................................... 18

Gallatin limestone .......... v ............................ 19

Oraovician system............................................. 19

Bighorn dolomite........................................... 19

Silurian system................................................ 20

Devonian system............................................... 20

Three Forks formation and Jefferson limestone............... 20

Carboniferous system.......................................... 21

Mississippian series........................................ 21

Madison limestone (lower Mississippian).........'........ 21

Brazer limestone (upper Mississippian)................... 21

Pennsylvanian series....................................... 22

Wells formation....................................... 22

Late Carboniferous (Permian series) to Recent....................... 22

Formations included........................................... 22

Carboniferous system.......................................... 23

Permian series............'................................. 23

Phosphoria formation.................................. 23

Triassic system................................................ 24

Woodside formation........................................... 24

Thaynes limestone........................................ 24

Ankareh shale............................................. 25

Jurassic system............................................... 25

Nugget sandstone.......................................... 25^

Twin Creek limestone..................................... 25

Beckwith formation........................................ 26

Cretaceous system............................................... 27

Upper Cretaceous series.:.................................. 27

Bear River formation... . .............................. 27

Aspen formation....................................... 28

Frontier formation...................................... 28

Hilliard and Adaville formations (?)..................... 29

3
4 CONTENTS.

Geology Continued.

Stratigraphy Continued.

Late Carboniferous (Permian series) to Recent Continued. page.

Cretaceous or Tertiary system.................................. 30

Evanston formation (?).......!............................. 30

Tertiary system. ............................................... 30

Eocene series (Wasatch group).............................. 30

Almy formation........................................ .-30

Knight formation............'........................... 30

Pliocene (?) series......................................... 31

Quaternary system.............................................I 31

Glacial deposits........................................... 31

Spring deposits. ........................................... 31

Alluvium and terrace gravels.............................. ' 33

Igneous rocks................................................. 34

Snake River basalt........................................ 34

Structure............................................................ 35

General features................................................... 35

Caribou Range................................................... 35

Snake River and Salt River ranges................................ 35

Bighole Mountains and Wyoming Range............................ 36

Teton Mountains................................................. 37

Mineral deposits.......................................................... 37

Phosphate............................................................ 37

General features................................................... 37

Distribution of phosphate deposits by structural districts............. 39

General conditions............................................ 39

Caribou Range, Idaho........................................ 39

Snake River and Salt River ranges............................. 40

General distribution....................................... 40

Pine Creek................................................. 41

Rainy Creek............................................. 42

Palisade Creek........................................... 44

Elk Creek................................................ 45

Indian Creek: .......................................:..... 46

Snake River.............................................. 47

Bighole Mountains and. Wyoming Range............... J........ 50

General features...............:......:.................... 50

Wyoming Range southeast of Snake River, in the vicinity of

Bailey Creek............................................ 50

Wyoming Range in the vicinity of Snake River............. 51

Bighole Mountains south of Victor, Idaho................... 52

North end of Bighole Mountains........................... 53

Teton Mountains............................................. 56

Jackson Hole and vicinity.................................... 58

Development of phosphate deposits................................. 59

Utilization of rock phosphate...................................... 60

Analyses of phosphate rock......................................... 61

Coal...........................................:...-::.........-.... 64

General occurrence. ............................................... 64

Willow Creek and Grays Lake area. . L .....<.,..: ;..L ................ 65

Pine Creek and Greys River area............. .:". .................... 66

Teton Basin and McDougal area......:............................. 67
CONTENTS. 5

Mineral deposits Continued.

Coal Continued. Page.

Sections of the coal beds........................................... 72

Character of the coal.......'...................'.................... 76

Gold and other minerals.............................................. 79

Water power............................................................. 81

Index.................................................................... 83

ILLUSTRATIONS.

PLATE I. Map of a part of southeastern Idaho and western Wyoming showing

the distribution of phosphate and coal deposits................ 12

II. A, Burlap tables arranged for saving fine gold near the mouth of

McCoy Creek on Snake River, Idaho; B, Public school building

at Irwin, Idaho, constructed of rhyolite blocks quarried in the

.vicinity; C, Auriferous gravels and alluvium carrying fine flakes

of gold...................................................... 78

FIOUEE 1. Map showing areas examined by the United States Geological Survey 

and the extent of phosphate reserves in eastern Idaho and western 

Wyoming on July 1, 1914..................................... 8

2. Map showing traverse along Pine Creek, Tps. 2 and 3 N., Rs. 43 and

44 E., Idaho.................................................. 42

3. Map showing traverse along Rainy Creek, T. 2 N., Rs. 44 and 45 E.,

Idaho........................................................ 43

4. Map showing traverse along Elk Creek, T. 1 S., R. 46 E., Idaho, and

T.39N., R.118W.,Wyo...................................... 45

5. Map showing traverse along Indian Creek, T. 2 S., R. 46 E., Idaho,

and T. 38N.,R. 118 W.,Wyo.................................. 47

6. Map showing traverse along Snake River canyon, Tps. 37 and 38 N.,

Rs. 116,117, and 118 W., Wyo.................................. 48

7. Map showing outstanding coal withdrawals July 1, 1914, and the 

approximate location of the coal-bearing formations in the area 

examined in eastern Idaho and western Wyoming............... 65

8. Section from the north end of the Bighole Mountains, Idaho, across 

Teton Basin to the Teton Mountains in the vicinity of Grand 

Teton, Wyo.................................................. 69

A GEOLOGIC RECONNAISSANCE FOR PHOSPHATE AND 

COAL IN SOUTHWESTERN IDAHO AND WESTERN 

WYOMING.

By ALFEED REGINALD SCHULTZ.

INTRODUCTION.

PURPOSE 'OF INVESTIGATION.

A reconnaissance examination of a part of southeastern Idaho and 

western Wyoming lying between meridians 110° 45' and 112° and 

parallels 43° and 44°, comprising an area of approximately 2,000 

square miles in the vicinity of Big Bend of South Fork of Snake 

River, was undertaken in 1912, for the purpose of collecting data for 

the elimination of lands from existing phosphate reserves if it was 

found that they contained no valuable deposits of phosphate. The 

writer spent three weeks in the region north of Snake River and 

north of the area examined in a reconnaissance by Schultz and 

Richards 1 in the autumn of 1911. As a result of this examination 

141,287 acres of withdrawn phosphate land was restored to agricultural entry. The data collected during the examination indicate 

that only a part of the phosphate land in this region was included 

in the phosphate reserves created by the withdrawals of December, 

1908, December, 1909, and July 2, 1910. The former boundary of 

the phosphate reserve in this region has therefore been so modified 

and extended as to include all the known phosphate areas. This 

has necessitated the withdrawal of 84,507 acres, leaving a net reduction in the outstanding Idaho phosphate withdrawals of 56,780 acres 

as a result of this preliminary examination. The withdrawn lands 

have been included in the phosphate reserve because it is known that 

they are underlain by phosphate deposits. It was found to be 

impossible during this short reconnaissance examination to trace the 

outcrops of the phosphate beds throughout the area, measure the 

thickness of the phosphate beds at short intervals, determine the 

amount of phosphoric acid they contain, measure the thickness of 

the overlying beds, and work out the structure in sufficient detail 

to determine in what tracts the phosphate beds occur near enough

1 Schultz, A. R., and Richards, R. W., A geologic reconnaissance in southeastern Idaho: U. S. Geol. 

Survey Bull. 530, pp. 267-284,1913.

7
8 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

to the surface to justify the classification of the tracts as phosphate 

land. As more detailed examinations of these lands are made, 

part of the area now withdrawn will no doubt be classified as nonLand included in phos- Phosphate land within Areas covered by detailed Areas covered by reconphate reserves on July 1,1914 Fort Hall Indian Reser- surveys; 1909,1910,1911, naissance surveys; 1906.

vation 1911 b, 19IZ b, and 1913 I9lla.and !9IZa

FIGURE 1. Map showing areas examined by the United States Geological Survey and the extent of 

phosphate reserves in eastern Idaho and western Wyoming on July 1,1914.

phosphate, and small outliers of phosphate rock may be found 

capping the ridges or included between fault blocks in areas not 

included in the outstanding phosphate reserves. Figure 1 shows 

the extent of the phosphate reserves on July 1, 1914, and the areas
INTRODUCTION. 9

in the phosphate region in southeastern Idaho and western Wyoming 

examined by the Survey since 1909, when the first extensive mapping 

Of the phosphate deposits in the Rocky Mountain region was 

undertaken.

EARLIER WORK.

The first geologic arid topographic examination in the area considered in this report was made in 1872, when the Snake River 

division of the Hayden Survey traversed the country from Ogden, 

Utah, to Fort Hall, Idaho; thence went up Snake River and the valley 

of Henrys Fork to its head, where an examination of the lakes, 

geysers, and headwaters of the Fire Hole Basin and vicinity were 

made; thence crossed the divide to the headwaters of South Fork 

of Snake River and went down that stream by way of Jackson Lake 

and the canyon of the South Fork to its emergence on the great 

lava-covered plains a few miles north of Fort Hall, Idaho. The 

geologic report by Frank H. Bradley * and the accompanying maps 

set forth admirably the general features along the route of travel 

and give much information that is of value in interpreting the structure of the region.

The entire area covered in the present reconnaissance survey was 

mapped topographically by the Hayden Survey in 1877, and a 

considerable part of the area was examined geologically by Orestes 

St. John, 2 whose report includes a fund of accurate information and 

represents reconnaissance work of high standard. In accuracy and 

quantity the data given in the text are well in advance of the geologic 

maps which accompany them. To the errors in the maps and in the 

interpretation of the structure are due in part the mislocation of the 

phosphate reserves as originally constituted, and one of the main 

results of the present examination consists in corrections of the 

errors in these old maps and information on the localities not visited 

by St. John or members of his geologic party. 

. More recently part of the area was examined by members of the 

United States Geological Survey. In 1906 the writer :1 and party, 

while making a reconnaissance examination of the deposits of central 

Lincoln County, Wyo., examined a portion of the area east of the 

Absaroka fault and south of Snake River. In the summer of 1910 

Eliot ' Blackwelder 4 and party traversed the region from Montpelier, 

Idaho, northeastward across the Preuss Mountains to Afton, Wyo., 

thence northward along the Salt River valley to Snake River, thence

1 U. S. Gcol. Survey Terr. Sixth Ann. Kept, pp. 189-271,1873.

2 U. S. Geol. and Geog. Survey Terr. Eleventh Ann. Kept., pp. 321-508,1879.

3 Schultz, A. R., Coal fields in a portion of central Uinta County, Wyo.: U. S. Geol. Survey Bull. 316, 

pp. 212-219, 1907; Geology and geography of a portion of Lincoln County, Wyo.: U. S. Geol. Survey 

Bull. 543,1914.

< Blackwelder, Eliot, A reconnaissance of the phosphate deposits in western Wyoming: U. S. Gcol. 

Survey Bull. 470, pp. 452-481, 1911.
10 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

down the Snake Eiver valley to Irwin, Idaho, and across the Snake 

River Range to Victor, Idaho, in the Tetbn Basin. Only cursory 

observations were made along the route from Montpelier to Victor, 

but on the west side of the Teton Range the party spent several 

days in more systematic geologic work. A similar study was made 

of the mountains south and east of Jackson Hole, including the 

canyon of Snake River in Wyoming. In the summer of 1912 Blackwelder again visited the region and made an examination of the rocks 

along the west side of the Teton Mountains from the Yellowstone 

National Park southward as far as Darby Creek, in the. Teton Basin, 

but the results of this investigation have not yet been published. 

In the fall of the same year E. G. Woodruff examined some of the 

coal beds in the vicinity of Horseshoe and Packsaddle creeks, on the 

northeast slope of the Bighole Mountains west of Driggs, Idaho.1

GEOGRAPHY.

ITINERARY.

In making the reconnaissance examination of the withdrawn 

phosphate lands in the Snake River, Bighole, and Teton mountains 

the party moved by rapid stages from the railway at Rexburg, 

Idaho, southeastward across the lava-covered plains to Snake River; 

thence southeastward to the mouth of the Snake River canyon near 

the State boundary, a few miles east of the Salt River valley. Along 

the route of travel only cursory observations were made, but on Snake 

River above the mouth of the canyon several days were spent in 

more systematic geologic work, in examining sections and making 

traverses, which proved beyond question that the phosphate beds 

are present in the hills on each side of Snake River and have been 

eroded in the valleys, for they occur at no place along Snake River 

from the lower end of the canyon eastward to the Absaroka fault. 

Similar studies were made of the mountains at a number of places 

across the range from Snake River northwestward to Moody Creek, 

southeast of Rexburg. Several days were spent in a study of the 

geology of the mountains along Indian, Elk, Palisade, Rainy, and 

Pine creeks. The party then moved across the Snake River Range 

over the divide at the head of Pine Creek into Teton Basin, where 

cursory examinations were made along the east flank of the Bighole 

Mountains southwest of Victor, Idaho, and along the west flank of 

the Teton Mountains east of Victor, in the vicinity of Moose, Fox, 

and Darby creeks. From Victor the party moved northwestward 

along the east base of the Bighole Mountains to Horseshoe Creek, 

where a somewhat more detailed study of the Bighole Mountains 

was made. Owing to the heavy fall of snow at' this time, which

»Woodruff, E. G., The Horseshoe Creek district of the Teton Basin coal field, Fremont County, Idaho 

U. S. Geol. Survey Bull. 541, pp. 379-388, 1914.
GEOGRAPHY. 11

completely masked the geologic formations exposed in the mountains, 

the work was discontinued, and the party returned to Rexburg over 

the lava-covered plains by way of Canyon Creek and the village of 

Teton.

TOPOGRAPHY AND SETTLEMENT.

The entire area examined lies within the Snake River drainage, 

basin. The drainage has a dominant northwesterly trend and is 

carried by Snake River, which in the eastern part of the area flows 

in a southerly direction and south of Jackson Hole goes between 

the Snake River and Salt River ranges in a deep canyon, at nearly 

right angles to the trend of the mountains and thence flows northwest. The principal tributaries are Gros Ventre, Hoback, Greys, and 

Salt rivers and Henrys Fork. Teton River is the largest tributary 

of Henrys Fork and drains all of Teton Basin.

Two types of country are included in the area examined lava

plains or plateaus and the rugged mountain tracts which are made 

up for the most part of deformed sandstone and limestone and 

metamorphosed schists, granites, and gneisses of pre-Cambrian age. 

With the exception of the northwestern part of the area, north and 

west of the Bighole Mountains, Teton Basin, and part of Snake 

River valley, the entire area is one of ragged, well-forested mountains. On the east side of the area the ranges trend nearly due 

north; in the central and western portions they run northwest. 

The mountain ranges are generally separated by narrow valleys, 

but some of the intervening spaces are wide, flat-bottomed basins, 

such as Teton Basin and Swan Valley Basin in Idaho, and Jackson 

Hole,, on Snake River, and Star Valley, on Salt River, in western 

Wyoming. These larger valleys, as well as the lava-covered plains 

in the northwestern part'of the area, are now fairly well settled by 

ranchmen1 and dry farmers, but in the mountain districts there are 

few inhabitants and no settlements of importance. A considerable 

part of the area is included in the Palisade, Teton, and Caribou 

national forests, and is primarily used for cattle and sheep grazing 

during the summer and as a source of timber. The mountainous 

portion, especially in the vicinity of Jackson Hole, is a celebrated 

game country that has become noted for its elk and is visited annually 

by hundreds of hunters in search of big game. Trails and wagon 

roads are common throughout the area, and good hunting ground is 

readily accessible from all the settlements or larger valleys. The 

United States Forest Service in recent years has built excellent roads 

and trails in that portion included within the national forests.

The only railroad in this region is the Oregon Short Line, which 

crosses the northwestern part of the area at Rexburg and St. Anthony 

and has a spur line from Ashton to Victor, in the Teton Basin. The 

same company in the fall of 1912 completed a second survey of a
12 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

railroad route from Idaho Falls, Idaho, to Jackson, Wyo., along 

Snake River. The approximate location of this alinement survey is 

shown on Plate I by a black line. It was reported in 1912 that 

construction work on this line was to begin in the near future. Rexburg, St. Anthony, and Driggs, Idaho, and Jackson, Wyo., are the 

main trading points, although there are numerous small villages and 

trading posts scattered throughout the area. Post offices are maintained at many places in this area.

GEOLOGY.

STRATIGRAPHY.

GENERAL SECTION.

The rocks of the region range in age from pre-Cambrian to Quaternary. The portion of the stratigraphic column from the preCambrian basal complex to the Devonian appears to be only partly 

represented, as there are unconformities separating the Cambrian 

from the pre-Cambrian, the Ordovician from the Cambrian, the 

Silurian from the Ordovician, and the Devonian from the Silurian. 

The portion of the column above the Devonian appears to be more 

fully represented from the basal Carboniferous to the top of the 

Jurassic, where there is another pronounced unconformity. At or 

near the end of Cretaceous time there was an interval of erosion, 

which is indicated by a marked unconformity. Subsequent intervals of erosion resulted in unconformities in the Tertiary.

The main features of the section are set forth "in the subjoined table.

Generalized section of sedimentary formations in southeastern Idaho and western Wyoming, 

in the area covered by this report.

System.

Quaternary.

Series.

Recent.

Pleistocene.

Group and 

formation. Thickness.

'Feet. 

0-250

0-1, 000

0-150

1-150

Character of strata.

Hill wash, talus, and 

landslide material.

Valley fill, terraces, 

flood-plain deposits, small-stream 

bottom lands, and 

travertine.

River terraces.

Boulders, gravel, and 

morainal material 

associated with 

hill wash.

Remarks.

Clay and soils derived largely

from the weathering of underlying rocks. Crood 

agricultural land.

Gold placers 

worked along 

Snake River. 

Similar deposits 

of auriferous

gravel occur both 

up and down 

Snake River beyond this area 

and on some Gilts tributaries.

No particular 

value.
S. GEOLOGICAL SURVEY BULLETIN 680 PLATE I

-ADoiviuin., terrace gravel*.

and spring deposits

Snake Kiver ±) as alt

(In part cbyered by

Phosphate "beds and

All rocks older than

the phosp"ha±e beds

Phosp"hate outcrop and

prospect

(Letters A,B, C, etc.jndica,t.e 

locations where samples were 

taken; dashed line, approximate 

location; X prospect)

Coal-prospect

Dip and strike of l>eds Station mentLonfid

in. St John!s T epor t

I 

Anticline Ilbads

MAP OF A PAET OF SOUTHEASTERN IDAHO AND WESTERN WYOMING

SHOWING THE DISTRIBUTION OF PHOSPHATE AND COAL DEPOSITS

1918

Geology by 

Alfred R.Schultz

Surveyed in I9IZ
STRATIGRAPHY. 13

Generalized section of sedimentary formations in southeastern Idaho and western Wyoming, 

in the area covered by this report Continued.

System.

Tertiary.

Cretaceous or 

Tertiary.

/

Cretaceous.

Series.

Pliocene (?)

Eocene.

(?)

Upper Greta-- 

ceous.

 :.:.-'

Group and 

formation.

Knight forD. mation.

3 Ou.

sCStg

i Almv forma- 

£ tloh.

Evanston formation (?).

Adaville formation (?).

Hilliard formation (?).

\

Frontier formation.

Aspen- formation.

Bear Eivcr for-

-UnRonformitv 

Thickness.

Feet. 

CO

500 ±

l.OOOi

(?)

(?)

(?)

3,000±

1,000-1,200

800 ±

Character of strata.

Marls, marly limestones, and calcareous conglomerates.

Red and yellow 

sandy clays, 

'shales sandstones, 

and concretionary 

limestones.

Red and yellowishwhite conglomerates, sandstones, 

and sandy clays.

In southwestern 

Wyoming, gray, 

yellow, and black 

carbonaceous 

shales and clays 

intcrbedded with 

sandstones containing some coal.

White, yellow and 

brow a carbonaceous shales and 

sandstones in 

southwestern Wyoming.

Gray and black 

sandy shales and 

sandstones in 

southwestern Wyoming. Weathers 

readily and affords a region of 

low relief.

Gray, buff, and 

yellow shales and 

sandstones, with 

coal beds. The 

shales and sandstones are soft and 

sandy and do not 

form pronounced 

ridges. Rocks are 

of Benton age.

Gray and black 

shales, shaly sandstones, and beds 

of compact gray 

sandstone, containing fish scales 

ofBentouage.

Black shale, shaly 

sandstone, and 

shaly limestone

vertebrate fossils.

Remarks.

No particular 

value.

Occurs east of 

Snake River.

Oc.curs east of 

Snake River. 

Thickness not 

measured. Probable source of 

water supply.

May be present 

along Snake River. Coal bparfne; 

in southwestern 

Wyoming.

Not recognized in 

this field. May 

be present beneath lava cover. 

Coal bearing in 

southwestern 

Wyoming.

Not recognized in 

this field. May 

be present beneath lava cover.

Coal-bearing 

throughout western .Wyoming 

and in eastern 

Idaho.

Oil bearing in 

southwestern 

Wyoming. Not 

measureoT north 

and west of Snake 

River.

Coal bearing in 

s o u t h w e s t e rn 

Wyoming and 

eastern Idaho.

, thin .and impure 

.to be of value.
14 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Generalized section of sedimentary formations in southeastern Idaho and western Wyoming, 

in the area covered by this report Continued. .

System.

Jurassic.

Triassic.

Carboniferous.

Series.

(?)

Lower Triassic.

Permian.

Fennsylvanian

Group and 

formation.

Beckwith formation.

Twin Creek limestone.

/

Nugget sandstone

Ankareh shale.

Thayncs limestone.

Woodside formation.

Phosphoria forWells formation.

Thickness.

Feet. 

900-4,000

800-1,200

500-1,000

200-500

700-1,000

800-1,000

75-400

. 500-1,000

Character of strata.

White, gray, yellow,

brown, and reddish-yellow shales 

and sandstones, 

with some limestones, red or gray 

conglomeratcs,and 

quartzite, containing Jurassic fossils.

Chiefly black, gray, 

and bluish-gray 

shaly limestones, 

the whole containing numerous Jurassic fossils.

Yellow, white, an,d

red quarzi tic sandstones.

Reddish-brown shale 

and shaly sandstone, with intercalated mottled

limestone.

Yellow, gray, and

blue chertv limestones, with some

yellow sandstones. 

"Bluish-gray limestones, very fossiliferous. Thin and

thick bedded

platy limestones.

Red and pasty

. brown shaly sandstones and shales, 

intercalated with

muddy limestone

lentils.

Rex chert member

and cliertv limestones at top, over 

yellow to brown 

sandstones, brown

to black shales,

oolitic limestone,

and phosphate

rock.

Sandy limestones, 

calcareous sandstones, and variable quartzites. Includes the Weber 

ouartzite and Tensleep sandstone as 

mapped in southern Idaho and 

western Wyoming.

Remarks.

Present throughout western Wyoming and eastern Idaho. NTot 

measured north 

of Snake River.

Present throughout western Wyoming and eastern Idaho. Entire section not 

measured north 

of Snake River.

Prominent ridtre

maker throughout region.

Has been prospected for copper 

in part of this region.

Present throughout region.

Present throughout western Wyoming and eastern Idaho.

Prospected for coal 

at many places 

in western Wvoming and eas'tern Idaho.

This formation is

present in western Wyoming 

and eastern Idaho, and has been 

mapped under 

various names 

whose limits are 

not the same. 

It probably includes both the 

Amsden and 

Morgan formations as mapped in some localities.
STRATIGRAPHY. 15

Generalized section of sedimentary formations in southeastern Idaho and western Wyoming, 

in the area covered by this report Continued.

System.

Carboniferous.

Devonian.

Silurian.

Ordovician.

Cambrian.

<-

Pre-Cambrian.

Series.

Mississippian.

Upper Ordovician.

Upper Cambrian.

Middle Cambrian.

Group and 

formation.

Brazcr limestone.

Madison 1 i m c - 

stone.

Thrceforks formation and 

Jefl'erson limestone.

-Unconformity 

-Unconformity 

Bighorn dolomite.

-Unconformity 

Gallatin limestone.

Gros Vciitre formation.

Flathead quartzite.

-Unconformity 

Thickness

Feet. 

200-1,000

1,000

330

50

350

200

SOO

250

Character and strata

Gray to blue, thickbedded limestones, some variegated reddishgray shales, and 

calcareous sandstone.

Dark gray to bluish 

limestones, thin- 

 boddedinpartbut 

also massive.

Black, gray, and 

brown shales,dark 

limestones, and 

thin-bedded

sandstones.

WTutish-gray dolomite, thin bedded 

and brittle. Fragmentary fossils.

Gray to cream-colored dolomite with 

rough pitted surfaces.

Gray oolitic and

congomeratic

limestones with

some shale. Limestones not as massive as overlying

bed. Contain few

fossils.

Gray, brown, red, 

and green shales 

and thin-bedded 

limestones.

Buff or pinkish

sandstone and 

quartzite with

some conglomerate.

Schists, granites,

gneisses, acd igneous rocks cut by

dikes of pegmatite and diabase. 

Some of the schistose and gneisslo

rock may nave a

sedimentary origin.

Remarks.

Present throughout western Wy oming and eastern Idaho In 

some localities 

this series of beds 

has been mapped 

as parts of Amsden and Morgan

formations.

Abundant marine 

fossils at many 

horizons.

Upper 200 feet dark

shale and thinbedded limestone, probably

represents the 

Threeforks formation. Lower 

150 feet of massive crystalline

limestone probably represents

the Jefferson

limestone.

In places appears 

to be absent.

Makes pronounced 

ridges and nearly 

perpendic u 1 a r 

ledges.

Weather readily 

and usually form 

low relief.

Prospected for copper, silver, lead, 

and gold.
16 PHOSPHATE AND COAL IN IDAHO AND WYOMING. 

PRE-CAMBRIAN TO CARBONIFEROUS (PENNSYLVANIANSERIES, INCLUSIVE).

GENERAL FEATURES.

In the extreme northeastern part of the area shown on the accompanying map lie the Teton Mountains. This range trends nearly 

north along the Idaho-Wyoming State line, lying chiefly in western 

Wyoming. It consists of a gentle westward-dipping monocline, 

crossed in the north by a low anticline that trends northwest and in 

the south by a low anticline that trends nearly due west and in its 

westward extension swings toward the northwest, nearly parallel to 

the Bighole Mountains. The strata in several places are broken by 

normal faults parallel to the monocline. Along the crest of the 

Teton monocline-and also along the axis of the northern transverse 

anticline the pre-Cambrian granite, gneiss, and schistose rocks are 

exposed. Against these older rocks on the southwest flank of the 

range rests a comprehensive sequence of Paleozoic strata, ranging in 

age from Cambrian to Carboniferous. The same rocks reappear on 

the northeast side of the transverse anticline. All the beds along 

this range, from pre-Cambrian to Carboniferous, were mapped and 

studied and detailed sections were measured by Eliot Blackwelder in 

1912, while making a study of the Grand Teton quadrangle, but no 

report has yet been published.

In the course of this reconnaissance examination it has been 

found advisable for the small-scale map to group all the beds older 

than the Phosphoria formation, including the pre-Cambrian, Cambrian, Ordovician, Silurian, Devonian, Mississippian, and Pennsylvanian, into one map unit, and the Phosphoria formation and the 

pre-Quaternary beds younger than that formation, which range in 

age from Permian (late Carboniferous) to Tertiary, inclusive, into 

another map unit.

In the greater part of the region examined the area occupied by 

outcrops of the Permian, Triassic, and Jurassic formations practically represents the lands that were regarded in the field ,as containing phosphate deposits in large enough quantities and near enough 

to the surface to be eventually suitable for economic development. 

Some of the beds overlying the phosphate deposits tend to become 

thinner toward the north, in eastern Idaho and western Wyoming, 

and in this part of the region the area that contains phosphate 

deposits within workable depth susceptible of economic development is probably represented by the outcrop of the beds from the 

Phosphoria formation up to the Beckwith formation, including the 

Twin Creek limestone and a considerable portion of the Beckwith.

The general distribution of the rocks older than the Phosphoria 

formation is shown on the* accompanying map by one pattern, withput'any attempt to indicate the distribution of the several forma-
STRATIGRAPHY. . 17

tions, and the distribution of the Phosphoria formation and younger 

pre-Quaternary beds is shown by the absence of a geologic pattern. 

Detailed examinations are needed to work out the distribution and 

thickness of the Phosphoria formation, which contains the phosphate beds, and the Frontier and Bear River formations, which 

contain the coal beds. The Quaternary deposits, exclusive of the 

glacial material, which is not mapped, are shown by a different 

pattern on the map.

FEE-CAMBRIAN ROCKS.

The oldest rocks that underlie the Paleozoic sedimentary series in 

this region consist of pre-Cambrian crystalline gneisses, granite, and 

schists of various kinds. This basal complex is composed largely of 

igneous rock, although some of the schistose and gneissic rocks may 

have had a sedimentary origin. The gneisses are in part coarsely 

crystalline, and the entire series shows the effect of metamorphism 

by pressure and is in places intricately folded and traversed by dikes 

of pegmatite and diabase. The age of this complex has heretofore 

been regarded as Archean, but the reasons for this assignment are 

not entirely satisfactory. Rocks of Algonkian age are represented 

in many parts of the Rocky Mountain province and may in part 

be represented in the intensely mashed and metamorphosed components of this basal complex. For the present, therefore, or until 

much more detailed work has been done, it seems advisable not to 

separate the rocks composing this basal complex, but to refer the 

entire series as a unit to the pre-Cambrian. Exposures of these older 

rocks occur hi the northeastern part of the area here described and 

form the central and eastern parts of the Teton Mountains. More 

detailed studies will no doubt determine the age of these rocks and 

definitely assign them either to the Algonkian or Archean or to both.

CAMBRIAN SYSTEM.

Upon the basement complex of the Teton and associated ranges 

was deposited unconformably in Paleozoic time a great thickness 

of sandstone, limestone, and shale. These strata include the Cambrian, the lowest known sedimentary beds exposed, Ordovician, 

Silurian, Devonian, and Carboniferous. The basal beds of the 

Paleozoic sedimentary series were formed from the detrital material 

derived from the disintegration of the schist and gneiss that formed 

the old continental land mass. Some of the members of these 

sediments consist of soft, poorly cemented, imperfectly stratified 

material, composed of coarse vein quartz, feldspar, fine conglomerate, 

and fragments of the underlying crystalline rocks. 

52756° 18 Bull. 680 2
18 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

FLATHEAD QUARTZITE.

In the Teton region and elsewhere in Wyoming the Flathead 

quartzite is the lowest of the Cambrian formations and consists 

essentially of pale-browji to reddish sandstone and quartzite. varying 

considerably in character both horizontally and vertically. In 

places the beds are streaked and spotted with a dark-maroon color, 

due to the presence of ferric oxide. In many places the beds are 

firmly cemented and constitute a typical quartzite, which forms 

pronounced ridges and gives rise to reddish-tinged outcrops that are 

very conspicuous and readily distinguished from the overlying beds. 

Near the top of the formation the sandstones become more or less 

argillaceous and are interbedded with gray or greenish shales that, 

as a rule, are less well exposed than the underlying massive sandstone 

or quartzite. The Flathead quartzite in this area is approximately 

250 feet thick and is of Middle Cambrian age. Exposures of similar 

beds have been observed by the writer in western Wyoming, in the 

Teton, Gros Ventre, and Wind River mountains, in the Hailey anticline, in Sweetwater Valley, in the Green Mountains, and in the 

Rawlins dome, and in northern Utah on the north flank of the 

Uinta Mountains.

GROS VENTRE FORMATION.

Conformably overlying the Flathead quartzite and grading down 

into the green^brown shales at the top of that formation is the 

Gros Ventre formation. This formation is approximately 800 feet 

thick and comprises green and brown clay shales, gray calcareous 

shales, thin beds of gray limestone, and flat-pebble limestone conglomerate. Good exposures of these beds are rare, because the 

soft shale erodes readily and the beds are generally concealed by 

soil and vegetation. However, excellent exposures may be observed 

in some of the deeper valleys or steep slopes where erosion is actively 

going on at the present tune. The name Gros Ventre formation as 

here used was first proposed by Blackwelder, in 1912, in connection 

with the preparation of a report, not yet published, on the stratigraphy 

of the Wind Kiver Mountains, in Wyoming. The name was chosen 

by Blackwelder from exposures of the beds in 'the eastern part of the 

Gros Ventre Range, at the head of Gros Ventre River. The same 

formation was traced by him into the Teton Mountains, which lie 

in the eastern part of the area treated in this report. The formation 

as described by Blackwelder has been identified by the writer in the 

Teton, Gros Ventre, and Wind River mountains of Wyoming, and he 

has observed beds of similar lithology and stratigraphic position in 

the Green Mountains, in Sweetwater Valley, in the Hailey anticline 

southeast of Lander, Wyo., and in northern Utah, on the north flank 

,of the Uinta Mountains. In all these localities the beds overlie a
STRATIGRAPHY. 19

red quartzite formation. The Gros Ventre formation is believed to 

be of Middle Cambrian age.

GALLATIN LIMESTONE.

Conformably overlying the Gros Ventre formation is the Gallatin 

limestone, of Upper Cambrian age. This formation consists of limestone, shale, and sandstone, the limestone greatly predominating. 

The lower part of the formation is composed of finely crystalline 

limestone of dark yellowish-gray color, clouded with brown, so that 

it has on weathering a brownish-yellow appearance. Overlying this 

limestone are thin beds of gray calcareous sandstone, shale, and limestone which consist more and more of relatively thin-bedded limestone near the top of the formation. The uppermost beds contain 

little or no shale and are more or less siliceous. As a whole the formation, which is approximately 200 feet thick, is primarily one of 

limestone in which the rocks are more or less siliceous and contain 

thin beds or nodules of chert.

Outcrops of deposits of similar lithology and stratigraphic position 

have been observed by the writer at many places in Wyoming in 

the Teton, Gros Ventre, Wind River, and Green mountains, in 

Sweetwater Valley, in the Hailey anticline southeast of Lander, and 

in Labarge Ridge, 40 miles northeast of Kemmerer and also extend 

northward into Idaho and Montana and eastward into the Big Horn 

Mountains.

ORDOVICIAN SYSTEM.

BIGHORN DOLOMITE.

Unconformably overlying the Cambrian sediments is the Bighorn 

dolomite, of Ordovician age. Exposures of this formation are seen 

in the Teton Mountains and at several places in the Snake River 

Range and in the Bighole Mountains in eastern Idaho. The distribution of the formation was not determined, and only a preliminary 

examination was made. The formation consists chiefly of massive 

dolomite of a cream to light-buff color, somewhat darker when 

weathered, but on freshly broken surfaces appearing mottled with 

dark-gray cloudy patterns. In places the beds contain a little chert 

in irregular horizontal lenses and masses. This siliceous material on 

weathering forms on the surface a ragged network, which is characteristic of the formation. In part this deeply pitted surface may be 

due to the difference in porosity of the rock and the manner in which 

some of the particles are cemented. In this area the formation is 

approximately 350 feet thick, but apparently it thins toward the 

southeast.

Exposures of the Bighorn dolomite have been observed by the 

writer in the Snake River and Bighole mountains in Idaho and in 

the Teton, Salt River, Gros Ventre, Wind River, and Green mountains and in the Hailey dome southeast of Lander, in Wyoming.
20 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

SILURIAN SYSTEM.

Unconformably overlying the Bighorn dolomite along the west 

flank of the Teton Mountains is a thin-bedded dense, brittle white 

slabby dolomite which is both distinctive and persistent. The 

individual beds range in thickness from 1 to 12 inches and show 

remarkable wavy stratification lines. On weathering some of this 

dolomite becomes as smooth as porcelain and shows on the surface 

numerous shallow depressions in rectangular pattern. Eliot Blackwelder, who has recently studied the Paleozoic formations along the 

west flank of the Teton Mountains and determined their areal- distribution, informs the writer that on Leigh Creek, on the west slope 

of the Teton Range, where he studied detailed sections of these beds, 

they aggregate about 50 feet in thickness, and are limited both above 

and below by unconformities. He has observed similar conditions 

at several places in the Wind River Mountains.

DEVONIAN SYSTEM.

THREEFORKS FORMATION AND JEFFERSON LIMESTONE.

Above the thin-bedded white dolomite of Silurian age and below 

the massive cliff-making ledges of the early Carboniferous (Mississippian) Madison limestone occurs a much less resistant group of 

black, green-gray, and brown shales interbedded with dark fetid 

sandstones and limestones, which in the Teton Mountains are approximately 350 feet thick. No measurement of their thickness was 

made in the Bighole Mountains, but it is believed that in this general 

region they range in thickness from 350 to 400 feet. The lower 100 

to 150 feet of beds are barren of fossils and consist of relatively massive crystalline limestone, darker than the overlying rocks. The

upper part of the series contains more shale and thin-bedded limestone, which as a rule are much lighter in color and in which fossils 

are frequently found, but the fossils are not conclusive enough to 

determine whether the beds belong to the Upper, Middle or Lower 

Devonian. The lithologic character of these beds, however, and 

their position in the stratigraphic section indicate that they closely 

resemble the Jefferson and Threeforks formations of the Yellowstone National Park.1 Although the beds in this area have not been 

separated into two formations, it is highly probable that the lower 

dark crystalline limestone or shale that gives the strong fetid odor 

represents the Jefferson lunestone and the overlying 200 feet of strata 

represents the Threeforks formation of the Park region.

Exposures of similar rocks were observed by the writer in 1906, 

while making a study of the coal beds in the vicinity of Labarge

1 U. S. Geol. Survey Geol. Atlas, Yellowstone National Park folio (No. 30), 1896; Geology of the Yellowstone National Park: U. S. Geol. Survey Mon. 32, pt. 2,1899.
STRATIGRAPHY. 21

Ridge, in T. 26 N., R. 113 W. sixth principal meridian, Wyo., about 

40 miles northeast of Kemmerer. In 1907 E. M. Kindle measured a 

section across the beds near the south end of Labarge Ridge and 

found that the Devonian in this locality is at least 1,080 feet thick. 

Regarding these beds, Kindle makes the following statement: *

In this section the gray and black limestone is preceded by beds holding a Cambrian fauna and followed by a limestone holding the usual Madison limestone fauna. 

The 80-foot shale formation at the top of the magnesian limestone appears to occupy 

the position of the Threeforks shale, but it is barren of fossils. Composition, texture, 

manner of weathering, and relationship to the other parts of the section all indicate 

the magnesian limestone to be the same as the Jefferson limestone of the Montana 

sections.

CARBONIFEROUS SYSTEM.

MISSISSIPPIAN SERIES. 

MADISON LIMESTONE (LOWER MISSISSIPPIAN).

The basal Carboniferous rocks are dark bluish-gray, relatively 

thin-bedded cliff-making limestones, in places consisting of massive 

gray-blue limestones with numerous beds of dolomite and a few thin 

beds of shale. The entire series is approximately 1,000 feet thick. 

The fauna collected from these marine beds at many horizons include 

many cup corals, Syringopora, Loxonema, ProducteUa, Spirifer centronatus, CTionetes, Euomphalus, etc., and according to G. H. Girty 

corresponds to the fauna of the basal portion of the " Wasatch limestone/' of the Wasatch Mountains of Utah, as described by earlier

writers.

BRAZER LIMESTONE (UPPER MISSISSIPPIAN).

Above the Madison limestone, apparently in conformable succession, occurs a series of massive light to dark gray limestones, weathering white to light gray, which represent the Brazer limestone of 

northern Utah and southeastern Idaho. The total series of beds at 

the south end of the area examined in this reconnaissance survey are 

approximately 1,000 feet thick, but in the northeastern part, in the 

Teton Mountains, they are only about 200 feet thick. Locally there 

is near the top a zone of dark shale about 15 feet thick. In places 

also the beds contain chert nodules in concentric and irregular forms 

and streaks of chert. The limestones are here and there specked 

with siderite and seamed with calcite or aragonite and at some horizons are abundantly fossiliferous. The fauna includes large cup 

corals with many fine septa, Syringopora, Liikostrotion, Martinia, 

and Productus giganteus.

i U. S. Geol. Survey Bull. 543, p. 37,1914.
22 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

PENNSYLVANIAN SERIES. 

WELLS FOBMATION.

The Brazer limestone is succeeded by a series of sandy limestones, 

calcareous sandstones, and quartzites of somewhat variable character, which represent the Wells formation of southeastern Idaho. 

At the type locality in Wells Canyon, in T. 10 S., R. 45 E., the 

formation consists of three portions having a total thickness of 

about 2,400 feet. Toward the north the thickness greatly decreases 

and a change in the lithology can be observed. The total series of 

beds at the south end of the area examined in the reconnaissance 

survey is approximately 1,000 feet thick; at the north end of the 

area they are only about 300 feet thick.

In the type locality 1 the upper and lower portions of the Wells 

formation are predominantly calcareous. The middle is mainly 

sandy. The upper limestone, 75 feet thick, consists of dense gray 

siliceous limestone or calcareous sandstone which weathers into white 

massive beds that are topographically conspicuous as cliff makers. 

Bluish-white chert occurs in bands 2 inches to 1 foot thick, and 

locally in ovoid nodules. Toward the base the chert becomes more 

nodular and darker. Silicified fragments of brachiopods project in 

little crescents from the weathered surface of the limestone. The 

most abundant fossils are Squamularia and a large Productus. The 

middle portion comprises 1,700 to 1,800 feet of calcareous sandstoneand quartzite, with a few thin beds of limestone, weathering white, 

red, or yellow and forming smooth slopes with few projecting ledges. 

No fossils have been found in this member. The lower portion is 

from 100 to 800 feet thick. The rocks are cherty limestones and 

interbedded sandstones and form prominent cliffs. They weather 

gray or reddish. The base of the formation is marked by a SchizopTioria zone, containing also Marginifera, Composite/,, Spirifer rockymontanus, Bryozoa, etc.

LATE CARBONIFEROUS (PERMIAN SERIES) TO RECENT. 

FORMATIONS INCLUDED.

For convenience in mapping and because of lack of information 

in many parts of the area all the beds overlying the Wells formation 

and underlying the Quaternary deposits in this area have been 

grouped together. These rocks, which correspond to the Laramie 

and in part to the Jura-Trias of the Hayden Survey reports on this 

area, comprise the Phosphoria formation (Permian), the Woodside 

formation, Thaynes limestone, and Ankareh shale (all Triassic), the 

Nugget sandstone, Twin Creek limestone, and Beckwith formation

1 Richards, R. W., and Mansfield, G. R., The Bannock overthrust: Jour. Geology, vol. 20, pp. 681-709, 

1912.
STRATIGRAPHY. 23

(all Jurassic), the Bear River and Aspen formations and the overlying 

coal-bearing sandstones and shales of the Frontier formation (all 

Upper Cretaceous), and the unconformably overlying undifferentiated 

Tertiary deposits. As most of these formations occur at a considerable distance stratigraphically above the phosphate horizon very little 

study was made of their distribution.

CARBONIFEROUS SYSTEM.

PERMIAN SERIES. 

PHOSPHORIA FORMATION.

The Phosphoria formation, of Permian age, overlies the Wells 

formation conformably, so far as observed in the course of this and 

earlier examinations. Its stratigraphic relation to the overlying and 

underlying formations in the Snake River Range is shown in the 

traverse sections along Pine, Rainy, and Indian creeks (figs. 2, 3, and 

5). The Phosphoria formation carries the economically valuable 

deposits of phosphate of this and the surrounding region, and in 

this area the entire formation ranges in thickness from 75 to 400 feet.

In the Preuss Range of Idaho, southwest of the area covered by 

this reconnaissance, the formation has been examined in detail and 

found to consist of two parts. The upper part is mainly chert 

and cherty limestone, and has been called the Rex chert member. 

This member ranges from a maximum thickness of about 450 feet 

to a feather-edge but usually is from 50 to 200 feet thick. The basal 

portion of the formation consists of 75 to 630 feet of alternating 

brownish shales, brownish sandstone, compact fetid limestones, 

usually lenticular, with one, two, or three zones bearing high-grade 

oolitic phosphate rock which contains 70 per cent or more of tricalcium phosphate and occurs in beds from 1 to 7 feet thick.

Within the area examined the natural exposures are for the most 

part not good enough to afford detailed sections. In all the districts 

where the outcrop is indicated on the map the formation was noted 

as composed of ledge-making cherts at the top (Rex chert member) 

and softer rocks shales and sandstones, with phosphate rock at 

the base. The upper portion locally, as on Pritchard Creek, south 

of Snake JRiver, near the north end of the Caribou Mountains, includes 

a thin bed of high-grade rock phosphate. At a few localities, as on 

Snake River and at the south end of the Blackfoot Range, a thin bed 

of phosphate was found overlying the Rex chert, but in no place is 

this bed known to be of commercial value. It is thought that careful 

measurements may show that the upper chert portion of the formation 

(Rex chert member) occupies a relatively greater part of the entire 

section in this area than it does farther south, but that the entire 

series thins toward the north. The areal distribution of this forma-
24 PHOSPHATE AND COAL IN -IDAHO AND WYOMING.

tion, so far as known, is practically represented by the line indicating 

phosphate outcrop on Plate I. Most of the area shown on the map 

without a geologic pattern is underlain by phosphate deposits, but 

more detailed work is required before the depth and attitude of the 

beds in that area can be determined.

TEIASSIC SYSTEM.

Triassic rocks, including the Woodside, Thaynes, and Ankareh 

formations, occur throughout western Wyoming and eastern Idaho. 

Exposures of these rocks have been examined in western Wyoming 

along the Meridian and Absaroka ranges, on Thompson Plateau, 

and in the Sublette, Salt River, and Wyoming mountains. In 

eastern Idaho they have been studied in the Bear River, Preuss, 

Blackfoot, Caribou, Snake River, and Bighole mountains. In all of 

this area these beds were for the most part mapped by the Hayden 

Survey as Jura-Trias but also in part as Carboniferous.

WOODSIDE FORMATION.

The Woodside formation conformably overlies the Permian Phosphoria formation and is composed mainly of russet-brown to olivegreen calcareous shales, intercalated with muddy limestone lentils 

in which fossil shells are so closely matted that their specific characters are often barely discernible. The formation in this area is from 

800 to 1,000 feet thick. Toward the top the limestones become a 

prominent feature of the formation, and throughout much of eastern 

Idaho the distinction between these and the overlying Thaynes limestone depends mainly upon the recognition of a cephalopod zone containing Meekoceras at the base of the Thaynes.

THAYNES LIMESTONE.

The Thaynes limestone, which apparently lies .conformably upon 

the Woodside formation, includes both thick-bedded and thinbedded, platy limestone and has a total thickness of 700 to 1,000 feet. 

The rock has a bluish-gray color on fresh fracture but weathers to 

light brown or buff and generally to an uneven sandy surface. The 

geologists of the Hayden Survey noted the Meekoceras zone at several 

places in the southeastern part of Idaho, in the Preuss and Blackfoot 

mountains, and mapped it hi the Salt River Range and in the Wyoming Range as far north as Virginia Peak. This zone was not 

observed north of Snake River, but very probably detailed work will 

prove that it occurs in the Snake River and Bighole mountains.
STRATIGRAPHY. . 25

ANKAREH SHALE.

 A red series ranging in thickness from 200 to 500 feet and composed of red shale and intercalated mottled sandstone unconformably overlies the Thaynes limestone and is known as the Ankareh 

shale. This formation and the two immediately underlying formations were originally described by Boutwell from observations in the 

Park City mining district, Utah. The similarity of the beds in the 

Idaho-Wyoming section to those around Park City has led to the use 

of the same formation names in this region. Red shales which are 

representative of the Ankareh shale were noted in the canyons of 

Pritchard and Fall creeks in the Caribou Mountains, in the Salt River 

and Wyoming ranges south of Snake River, and along the east side 

of the Snake River Range, the west side of the Bighole Mountains, 

and the southwest side of the Teton Mountains north of Snake River.

JURASSIC SYSTEM. 

NUGGET SANDSTONE.

The Nugget sandstone overlies the Ankareh shale conformably and 

consists of massive red sandstone with white conglomeratic sandstone in places at the base and top of the formation. Locally the 

sandstone is silicmed to a quartzite. Owing to its massive and resistant character the Nugget sandstone forms high ridges with broad 

rounded slopes. The formation thins toward the north, and in the 

north end of the Caribou Range south of Snake River is approximately 1,000 feet thick. The thickness of the Nugget sandstone was 

not measured north of Snake River in either the Bighole or the Snake 

River mountains, but the formation was recognized throughout the 

area examined in 1911 and 1912 along Fall Creek and Pritchard 

Creek, in the Caribou Range, and at several places in the Snake 

River, Bighole, Teton, Wyoming, and Salt River ranges. The 

formation thins toward the north, and its thickness is believed to 

range from 1,000 feet near the south end of the area to approximately 500 feet at the north end.

No fossils were found in the formation in this area, but Jurassic 

fossils were obtained by Gale from corresponding beds in northwestern Colorado, and the formation is therefore now classified as 

Jurassic.

TWIN CREEK LIMESTONE.

The Twin Creek limestone overlies the Nugget sandstone, and, so 

far as observed in the course of this examination, is conformable to 

it. The beds consist principally of grayish-white shaly limestones and 

are readily recognized wherever they are exposed. The Twin Creek 

becomes thinner toward the north and is approximately 1,200 feet 

thick on Fall Creek, in the northern part of the Caribou Range, and
26 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

800 feet at the north end of the area examined. The beds in this 

formation are exposed in this area on Bailey Creek and Little Greys 

River in Wyoming and in the Snake River and Bighole mountains in 

Idaho. On Rainy Creek in the Snake River Range, 450 feet of beds 

were measured below the Beckwith-Twin Creek contact without 

seeing the base of the formation. In some areas in Idaho and Wyoming these beds were for the most part mapped by the geologists of 

the Hayden Survey as a portion of their Laramie. They have been 

traced by the writer from the southwest corner of Wyoming northward to Snake River and have been examined at many places in 

eastern Idaho south of Snake River, but were noted north of Snake 

River in this examination only on Rainy Creek and at several places 

between the Darby and Absaroka faults, and on the northeast flank 

of the Bighole mountains in the vicinity of Horseshoe Creek. Their 

occurrence at these localities clearly indicates that the Twin Creek 

limestone is exposed at a number of places in the Snake River and 

Bighole mountains. The fauna includes Pentacrinus asteriscus, 

Camptonectes pertenuistriatus, Trigonia americana, Astarte meeki, 

Thracia weedi, GrypJiaea calceola, Ostrea, PJioladomya, and Pleuromya.

BECKWITH FORMATION.

The Beckwith formation overlies the Twin Creek limestone and 

is extensively exposed in the northeastern part of the Bighole Mountains and in the area east of the main crest of the Snake River Range, 

or between the Darby and Absaroka faults. The exposures of these 

beds and their relations to one another are indicated hi the sections 

along Pine and Rainy creeks (figs. 2 and 3, pp. 42, 43). Beds of Beckwith age have been examined and mapped by the writer in the Salt 

River, Snake River, and Wyoming mountains in western Wyoming 

and in the Snake River, Preuss, Caribou, and Blackfoot mountains in 

eastern Idaho. In all these localities the beds were mapped by the 

geologists of the Hayden Survey as part of their Laramie formation. 

The Beckwith formation consists of reddish or chocolate-colored 

sandstone and shale, associated with whitish to grayish limestone and 

red conglomerates, and in this general region ranges in thickness from 

900 to 4,000 feet. The upper member consists of calcareous sand-^ 

stone, red conglomerate, and massive gray limestone. In 1906 the 

"writer collected fossils from these beds on Hoback River, on Meridian 

Ridge, and at numerous other localities in the Hoback Range in 

western Wyoming. 1

1 Schultz, A. R., Geology and geography of a portion of Lincoln County, Wyo.: U. S. Geol. Survey Bull. 

543, pp. 53-54, 1914. Mansfield, G. R., and Roundy, P. V., Revision of the Beckwith and Bear River 

formations of southeastern Idaho: U. S. Geol. Survey Prof. Paper 98, pp. 75-84,1916.
STRATIGRAPHY. 27

CRETACEOUS SYSTEM.

TIPPER CRETACEOTTS SERIES.

BEAR RIVER FORMATION.

Overlying the Beckwith formation occurs a series of beds whose 

thickness in this area was not determined but is believed to be 

approximately 800 feet. They consist of gray limestones, calcareous 

sandstones, dark-colored shales, thin and impure coal bedsrbrownish 

and gray sandstone, and light calcareous deposits. The beds are 

very widely distributed south of Snake River, north of the old Lander 

trail, and east of Willow Creek, lying for the most part on the west 

flank of the Caribou Range or between that range and Willow Creek. 

Beds of the same type and of the same age occur in Wyoming between 

the Salt River and Wyoming mountains, f orming part of the crest of 

the Greys Ridge anticline. Good exposures were observed along 

Snake River east of the Salt River and Snake River ranges and also 

east of the Wyoming Mountains near the mouth of Hoback River. 

Similar beds were noted at many places along the strike of the beds 

north of Snake River, in the area between the Darby and Absaroka 

faults. The formation is coal bearing in many places, but the coal 

beds are too thin and impure to be of commercial value, although 

they may serve locally as a source of coal for domestic use.

The beds of the Bear River formation throughout most of the 

field have the same dip and strike as the underlying formations and 

may therefore readily pass as a conformable series. It is known, 

however, by the absence of the Lower Cretaceous, that an unconformity of considerable magnitude exists between the Bear River 

formation and the underlying Beckwith formation.

The fauna collected from the Bear River formation in the vicinity 

of Snake River includes Pyrgulifera humerosa, Campeloma macrospira, Corbula pyriformis, CorUcula durkeei, Unio, Viviparus, and 

Goniobasis. In the fall of 1912 E. G. Woodruff collected a small lot 

of Cretaceous fossils on Pine Creek in sec. 19, T. 3 N., R. 45 E., in the 

Bighole Mountains, about 5 miles southwest of Victor, Idaho. Among 

these T. W. Stanton identified Corbula pyriformis, Corbicula durkeei, 

Pyrgulifera Tiumerosa, and Pachymelania sp. In 1911 the writer 

made a hurried examination of similar beds in the Fall Creek basin, 

along the west flank of the Caribou Mountains, Idaho, at a locality 

2 miles northeast of Herman post office, northeast of Grays Lake. 

About a quarter of a mile east of the east quarter corner of sec. 25, 

T. 3 S., R. 43 E., a few fragmentary fossils were collected from beds 

lithologically resembling the Bear River formation of western Wyoming. A similar fossil bed was seen where Fall Creek enters the canyon. It is more than likely that St. John and Peale, of the Hayden 

Survey, mapped these beds, together with a part of the Beckwith
28 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

and Twin Creek formations, as Laramie on the basis of similar freshwater fossils. T. W. Stanton, who examined the fossils collected 

in T. 3 S., R. 43 E., reports on them as follows:

I have examined the small lot of fresh-water fossils which you recently handed me 

from a locality northeast of Grays Lake, on the west slope of the Caribou Range, about 

2 miles east of Herman, Idaho. It has not been found practicable to develop the 

fossils by etching or otherwise, and the preservation of the specimens on weathered 

surfaces is not satisfactory. Fragments of Unio and casts of Viviparus or Campeloma 

are recognized, and Goniobasis and possibly other genera of fresh-water gastropods 

may be represented. In my opinion this fauna is Cretaceous, but on account of the 

absence of definitely characteristic forms I am unable to determine whetherit belongs 

to the Bear River formation. Similar imperfect fossils have been collected in Montana 

in rocks that are provisionally referred to the Kootenai formation. Additional good 

collections and accurate stratigraphic data concerning the rocks that were mapped 

as Laramie by St. John in this general region are greatly desired.

ASPEN FORMATION.

The Aspen formation is composed of black shale, dark-drab to gray 

sandy shale, and gray sandstone. In places the sandy shale weathers 

into small splintery fragments and the harder sandstone layers produce long rounded hills of peculiar gray color. Outcrops of these 

beds were observed along the Wyoming Range in the area between 

the Absaroka and Darby faults and on the northeast flank of the 

Bighole Mountains in the vicinity of Horseshoe and Packsaddle 

creeks. No carefully measured section of these'beds, was made in 

any of these localities, but the total thickness approximates 1,000 

feet. Beds in this formation yield oil in southwestern Wyoming, and 

throughout the area examined in a previous survey 'contain abundant 

fish scales, but only a few good collections of fossils were obtained 

from the beds.

FRONTIER FORMATION.

Conformably overlying the Aspen formation occurs a series of 

sandstone, clay, shale, and shaly sandstone beds with which are 

associated beds of carbonaceous shale and of coal, the entire series 

approximately 3,000 feet thick, which constitute the Frontier formation. The sandstone is grayish white and yellow and occurs both in 

thick massive beds and in thin shaly beds. The coal beds are not 

continuously exposed for any great distance, nor are the associated 

strata sufficiently characteristic to render correlation certain, but 

it is known that this formation is coal bearing throughout the region 

extending from southern Wyoming northward to the north end of 

the Bighole Mountains, southeast of St. Anthony, Idaho. Coal beds 

and other strata belonging to the Frontier formation were observed 

in the Wyoming Range at the mouth of Hoback River south of Jackson, Wyo.; in the Greys River area, in western Wyoming south of 

Snake River; in the Snake River and Bighole mountains north of
STRATIGRAPHY. 29

Snake River; in the area between the Absaroka and Darby faults; 

and on the northeast side of the Bighole Mountains in the vicinity 

of Horseshoe and Packsaddle creeks, where the beds are exposed on 

both sides of the overturned fold or faulted anticline. The fauna of 

the Frontier formation consists of Ostrea glabra, Cardium, Mactra, 

Anomia, Inoceramus, Goniobasis, Turritella, Barbatia, Corbula, Gyrodes, PJioladomya, Avicula, Ostrea, and Glauconia.

On Packsaddle Creek in the SW. J sec. 24, T. 5 N., R. 43 E., occurs 

an outcrop of soft gray sandstone which dips 50° S. 55° W. and which 

has been quarried for the purpose of building a dam at the reservoir 

in sees. 18 and 19, T. 5 N., R. 44 E. In this sandstone the writer 

found fragments and several complete casts of Inoceramus labiatus, 

Inoceramus erectus, and other associated fossils of the Frontier formation which indicate that these beds and their associated coals are of 

Colorado age.

Woodruff in the fall of 1912, while examining the coals in this 

vicinity, collected a small lot of Cretaceous fossils in the NW. 1 

sec. 6, T. 4 N., R. 44 E., and at the Brown Bear mine, in the SE. J 

sec. 25, T. 5 N., R. 43 E., of which T. W. Stanton identified the following :

NW. isec. 6, T. 4N., R. 44 E.: 

Modiola sp. 

Cardium sp. 

Corbicula? sp. 

Corbula undifera Meek. 

Neratina.

SE. i sec. 25, T. 5 N., R. 43 E.: 

Cardium sp. 

Lucina? ep. 

Corbula sp.

Undetermined material. 

Shells.

These fossils suggest the Mesaverde formation of the Rock Springs 

field, but they are not distinctive enough to warrant positive identification of the horizon. There are some similar forms also in the 

Adaville formation in western Wyoming.

HILLIARD AND ADAVILLE FORMATIONS (?).

Tlie beds immediately overlying the Frontier formation in southwestern Wyoming constitute the Hilliard formation, which consists 

of dark-colored sandy shale, clay, and shaly sandstone, chiefly of 

Colorado age but in part of Montana age. The entire series is soft 

and weathers readily, forming marked depressions in which comparatively few exposures are seen. In southwestern Wyoming the Hilliard formation is overlain by the coal-bearing Adaville formation, 

also of Montana age. Beds belonging to the Hilliard and Adaville 

formations were not observed in this area in the course of the reconnaissance examination. This portion of the Upper Cretaceous series 

may, however, be present in some parts of the Snake River or Bighole mountains, but the examinations thus far made indicate that 

all the Cretaceous beds exposed at the surface are older than the
30 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Adaville and Hilliard formations. Until the area is studied in detail 

it will not be possible to state definitely whether or not beds belonging to these formations occur in surface exposures in the Snake River 

and Bighole mountains or whether they are present in any part of 

the field beneath the lava-covered plains of the Teton Basin.

CRETACEOUS OR TERTIARY SYSTEM.

EVANSTON FORMATION (?). 

The deposition of the Adaville formation in southwestern Wyoming 

was succeeded by a long period of folding, faulting, and erosion, 

after which was laid down a series of gray, yellow, and black carbonaceous shales, clay, and white and yellow sandstone, which 

make up the Evanston formation. It is not positively known whether 

or not this formation, 1 which carries coal in the Hoback River basin 

and in the vicinity of Evanston, Wyo., is present in the area covered 

by this report. Beds resembling the Evanston formation, however, occur on the east side of Snake River south of Jackson, Wyo., 

where coal-bearing beds lie apparently conformably below the Almy 

formation.

TERTIARY SYSTEM. 

EOCENE SERIES (WASATCH GROUP). 

. . ALMY FORMATION.

The Almy formation, which may be equivalent to the Pinyon conglomerate of the Yellowstone Park region, is well exposed between 

Snake and Hoback rivers in Tps. 39 and 40 N., R. 116 W., Wyoming, 

where, in beautiful weathered exposures, conglomerate representing 

this formation may be traced from Hoback River northwestward' to 

Snake River. The beds here strike N. 32° W. and dip about 25° NE. 

At no other place in the area examined were these deposits observed. 

The conglomerate is overlain by later Tertiary deposits.

KNIGHT FORMATION.

Beds belonging to the Knight formation were identified southeast 

of Cheney post office, on the east side of Snake River, overlying the 

Almy formation. They consist of red and yellow sandy clays, shales, 

sandstones, and concretionary limestones and extend eastward south 

of the Gros Ventre Mountains, connecting with the beds observed 

north and east of the Hoback River basin.

i Veatch, A. C., U. S. Geol. Survey Prof. Paper 56, pp. 76-87,1907. Schultz, A. R., U. S. Geol. Survey 

Bull. 543, pp. 68-71,1914.

\
© 

STRATIGRAPHY. 31

PLIOCENE (?) SERIES.

At Snake River in T. 1 S., R. 45 E., about 3 miles southeast of 

the mouth of Bear Creek, is a small area of calcareous conglomerates 

and inferior lithographic limestone which were provisionally mapped 

as Carboniferous by St. John, but which appear in the light of recent 

detailed study in Idaho farther to the south to be Tertiary lake 

beds, probably of Pliocene age. This correlation is made purely on 

lithologic and structural grounds. Similar conglomerates were 

observed along the. west flank of the Snake River Range at several 

places along Snake River between Alpine and Irwin, and on Indian 

and Elk creeks.

QUATERNARY SYSTEM. 

GLACIAL DEPOSITS.

Glacial deposits consisting of old eroded drift were observed on 

the slopes of the Teton, Bighole, and Snake River mountains, and 

fresh moraines were seen in some of the mountain valleys. In some 

of the smaller valleys near the summits of the higher peaks remnants of the receding mountain glaciers were seen, which earlier in 

the summer had extended much farther down the valley. In one 

place north of the canyon of the Snake one of these small valley 

glaciers had extended during the previous year nearly to the mouth 

of the valley, where it joins Snake River, and the moraine left by 

the melting ice could be distinctly seen through the entire distance, 

approximately half a mile.

SPRING DEPOSITS.

In certain parts of the area described in this report, nota'bly 

along Snake River and Fall Creek, occur deposits of travertine and 

numerous hot springs, many of which are depositing tufa at the 

present time. These hot springs may represent the southwestern 

extension of conditions similar to those that gave rise to the numerous renowned hot springs in the region of the Yellowstone National 

Park. F. H. Bradley,1 of the Hayden Survey, visited some of these 

springs in 1872 and gave an excellent account of the springs and 

their deposits. Regarding the hot springs of Snake River, which 

occur along the Darby fault in T. 39 N., R. 116 W., Wyoming, he 

makes the following statement:

A small cluster of these [Warm Springs] escape among the gravel on the edge of 

the river in the south side, emitting an abundance of sulphureted hydrogen. Though 

somewhat mixed with the river water, they gave a temperature of 117°. About a 

hundred yards below this a group of calcareous springs has built up a dam of tuff so 

as to flood several acres about the vents, which are now inaccessible. The general 

flow from the pool gave a temperature of 94°.

i U. S. Geol. Survey Terr. Sixth Ann. Kept., p. 269, 1873.
32 PHOSPHATE AND COAL IN, IDAHO°AND WYOMING.

The writer visited this locality in 1906 and found the condition 

of the springs much the same as in 1872, at the time of Bradley's 

visit. He observed, however, other hot springs not described by 

Bradley. Some of these lie on the gravel bench on the south side 

of Snake River. Over one of the larger of these springs a bathhouse has been erected. A number of other springs occur in this 

locality on the gravel terrace near Counts's ranch.

On the lower part of Snake River both spring deposits and hot 

springs were observed at several places from Alpine to Heise, Idaho. 

All the springs at Alpine, Blowout, and Heise, on'Fall Creek, and in 

the lower Conant Valley, Idaho, occur along the fault line between 

the Caribou Range and the Snake River valley. It is very probable 

that similar deposits will be found at other localities in the mountains along this fault line as soon as a more detailed examination of 

this region is made. At Heise, on Snake River, in the SE. | sec. 25, 

T. 4 N., R. 40 E., is the most northwestern hot spring observed in 

the course of the reconnaissance examination 'along this fault line. 

This spring is mentioned by Bradley, 1 who says:

Some 3 or 4 miles below the mouth of this last canyon [lower Snake River canyon] 

a small hot spring, 4 or 5 feet across, stands on the north bank of the river about 20 

feet above the bottom. This was not visited by any of our party but was reported by 

our guide to be too hot for one to hold his hand in it for more than half a minute. 

White-spring deposits were seen from a distance at several points on the north bank, 

but there is believed to be no flow at these points at the present time.

About 18 miles southeast of this locality, at the lower end of Conant 

Valley, in T. 2 N., R. 43 E., occurs another hot-spring deposit on 

the south side of Snake River. Of these deposits Bradley says:

At the base of the mountain on the southwest side of the valley, just above the 

head of this lower canyon [lower Snake River canyon], calcareous deposits from 

now extinct springs form a heavy mass reaching about 100 feet up the mountain 

side.

In sec. 29, T. 1 N., R. 43 E., on Fall Creek, immediately west of 

the fault along the east side of the Caribou Range, where the crest 

of the anticline in the Paleozoic beds crosses the creek, occur numerous warm springs. Some of these are on the south side of the creek 

and several in the bottom of the stream. The largest one, which 

supplies a stream that fills an 8-inch pipe, comes in on the north 

side of the creek right at the water's edge. The water from most 

of these springs is luke warm and carries hydrogen sulphide. Considerable sulphur is deposited around the springs and in the stream. 

The stones and ground are coated with greenish-yellow algae. Travertine and other spring deposits are built up around the springs, 

the rims and domes of which are several feet in height.

1 Bradley, F. H., op. cit., p. 271.
STRATIGRAPHY. v 33

The largest spring deposits and the hottest water observed along 

the fault between the Snake River valley and the Caribou Mountains occurs on Shake River southwest of Blowout, in sees. 13 and 

24, T. 2 S., R. 45 E.; and in the southwest quarter of T. 2 S., R. 46 E. 

One of these springs on the east bank of Snake River is now utilized 

for a bathhouse. Regarding this group of springs Bradley, 1 who 

visited them in 1872, makes the following excellent statement:

Here also is located a cluster of warm springs, making calcareous, sulphurous, and 

ealine deposits. The largest spring, the Washtub, has built up a flaring table, 1 foot 

high, of an oval form, measuring about 4£ by 7£ feet, upon a mound consisting of 

calcareous mud, scarcely solidified, of from 5 to 7 feet above the creek bottom in 

which it stands. The central table has contracted so as to crack across diagonally, 

and the flow now escapes at its western base, depositing a fine mud tinged in the full 

pools with a faint sulphur-yellow, but pure white in the dry ones. These pools 

cover the mound in descending steps of great beauty. The present flow is southward, though it has been on all sides in succession. The deposit on the surface of

the mound is still very soft and showed at the time of our visit (Oct. 6) the tracks of 

a email bear, who had recently investigated the wonders of the mound, even setting 

hia foot on the central table. One mound, no longer active, is 5 feet high, with a 

circular base of about 5 feet diameter and an oval summit of about 1 foot by 6 inches. 

Many small springs escape along the bank for a hundred yards or more. The deposits 

vary greatly in color. At some points the odors of sulphurous acid and of sulphureted 

hydrogen were quite noticeable. The older deposits have built up a bank 10 feet 

high along the base of the terrace, and the beavers have taken possession and have 

dammed up on it the waters of the cold springs which flow from the second terrace 

at short intervals along this plain. On the opposite shore two considerable springs 

have built up their deposits against the foot of the mountain, one of which appears 

to be nearly dead. The highest temperature observed here was 144°. The Washtub gave 142°, and others 142°, 140°, 90°, 88°, etc

Similar springs occur on- the bottom lands along the west side of 

Snake River and drain into the sloughs and low depressions on the 

gravel terrace bench.

ALLUVIUM AND TERRACE GRAVELS.

Along all the large streams in this region occur considerable deposits of washed soil and gravels of Quaternary age. Some of the 

gravels along Snake River and its tributaries are washed for gold. 

For the most part the alluvial bottoms are small and are confined 

to narrow strips along the streams or are cut out entirely where the 

stream has intrenched itself in the lava bed. The largest of the alluvial bottoms occur along the Salt River valley and around Jackson, 

Wyo., along Snake River above the canyon, .and in places along 

Snake River below the canyon. In addition to the alluvial bottoms 

along the larger streams, gravel, sand, and silt deposits form large 

alluvial fans in the Teton Basin and Snake River valley and occupy 

narrow strips in the bottoms of the mountain valleys.

i Bradley, F. H., op. cit., p. 2C9. 

52756° 18 Bull. 680 3
34 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

IGNEOUS EOCKS.

SNAKE RIVER BASALT.

Nearly all the northwestern part of the aVea is covered by 

igneous rocks, which consist largely of a series of lava flows whose 

relation to one another has not been accurately determined. There 

appear, however, to be two fairly distinct types of rock, which belong 

to the series of successive lava flows grouped by Russell under the 

term Snake River lava. The older lavas are rhyolites that cover 

extensive areas; the later basalt is less widespread in its distribution 

and is the most recent extrusive flow that occurs along the lower 

depressions. The greater part of the igneous rock is dense and in 

cliffs shows the development of irregular columnar jointing, but minor 

scoriaceous and cellular facies are found, especially near the margins 

of the flows. The surface of the basalt has a comparatively fresh and 

recent appearance, and the soil cover is thin except where it has been 

augmented by alluvial agencies. The number of flows has not yet 

been worked out in detail. It is evident that there are several, 

because of the intercalation of scoriaceous and tuffaceous lentils. 

The exact geologic range of the flows has not been determined, but 

it appears that some at least belong to the Tertiary and are of 

Pliocene age, while others, from their relation to the deformed beds 

of probable Pliocene age, are Quaternary.

The older lavas consist primarily of a massive flow which is uniform 

in composition but varies considerably in physical appearance. These 

rocks range from a few feet to a thousand feet or more in thickness 

and extend well up on the flanks of the Caribou, Snake River, Teton, 

and Bighole mountains. At the north end of each of these ranges 

the lava lies at elevations as high as the main part of the range, and 

within a short distance it completely conceals the northward extension of the Paleozoic rocks of which the range is composed. In the 

Teton Basin and along Snake River southwest of the Snake River 

Range large bodies of more recent Snake River basalt overlie the 

older flows. The basalt sheets are from a few feet to 200 feet thick 

and consist of dark-gray to bluish-black more or less vesicular rock 

containing some crystals of feldspars and ferromagnesian minerals.

The Tertiary beds on the west flank of the Caribou Range are overlain by igneous rocks or basalts similar to those which occur in the 

canyons farther to the north and west. The greater portion of the 

igneous rocks represents part of the extensive lava flows of the Snake 

River. Plains, which have been referred in southern Idaho mainly to 

the Tertiary by Russell and in the Yellowstone National Park region 

to the Neocene by Hague and Iddings. There are, however, within 

this general area a number of subordinate cones, many of which are 

broken and shattered and undoubtedly served as the outlets for the
STRUCTURE. 35

later lavas that surround them. Some of these are of Pleistocene or 

Recent age, if the Tertiary beds are correctly determined as Pliocene.

STRUCTURE. 

GENERAL FEATURES.

The geologic structure of the area examined is rather complex, and 

no attempt was made to decipher it in detail. The mapping of the 

phosphate beds on some of the streams in the area, however, permitted the structure of some of the larger units to be worked out with 

considerable accuracy. The main mountain ranges are more or less 

parallel and extend in a northwesterly direction across the area 

examined. The one farthest to the southwest south of Snake River 

is the Caribou Range. Northeast of the Caribou Range lie the 

Snake River and Salt River ranges, the former north and the latter 

south of Snake River and east of Salt River. Immediately to the 

northeast of these are the Bighole and Wyoming ranges, which in 

places lie so near to the Snake River Range as to be taken as a part 

of it. Northeast of these parallel mountain ranges, in the northeastern part of the area, lies a high range known as the Teton Mountains, which in western Wyoming extends in a northerly direction 

from Snake River to the Yellowstone National Park.

CARIBOU RANGE.

The Caribou Range, which forms the southern boundary of the 

area examined, has a very complex structure and consists of an 

anticlinorium, as indicated by the sections traversed by the writer 1 

in the autumn of 1911, along Fall and Tincup creeks. A large thrust 

fault extends along the east flank of the Caribou Range and probably 

represents the northward continuation of the fault that lies for the 

most part in Snake and Salt River valleys, west of the Salt River 

Range. It is along this fault that the numerous hot springs referred 

to are located. Minor faulting was observed at several places in the 

Caribou Range, but no attempt was made to study the relation of 

these faults to one another.

SNAKE RIVER AND SALT RIVER RANGES.

The Snake River and Salt River ranges consist of a series of rugged 

peaks and hills that have a general northwesterly course, extending 

from western Wyoming to the great lava plains southeast of St. 

Anthony, Idaho. The ranges were formerly continuous but have 

been separated by Snake River, which has forced a narrow passage 

through them. The Snake River Range lies north of the canyon and 

the Salt River Range south of it. The ranges lie immediately east of

i Schultz, A. R., and Richards, R. W., U. S. Geol. Survey Bull. 530, figs. 33 and 34,1913.
36 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

the broad valleys of Snake and Salt rivers, which separate them from 

the Caribou Mountains. The Snake River and Salt River ranges 

have a very complex structure and consist of parallel anticlines and 

synclines, which are in places overturned and closely folded and with 

which is associated considerable faulting. A large thrust fault 

extends along the east flank of the ranges and represents the northward continuation of the Absaroka fault.1 This fault, in which the 

thrust has come from the west, approximately separates the Snake 

River and Salt River ranges from the Bighole and Wyoming ranges. 

As a result of this thrust rocks of Carboniferous age are brought in 

places into juxtaposition with rocks of Cretaceous (Colorado) age. A 

short distance west of and more or less parallel to the Absaroka fault 

is another fault, which marks approximately the western limit of 

the phosphate-bearing beds in the Snake River Range. All the phosphate exposures observed in this part of the range lie between.these 

two faults. Minor faulting was observed at several places, but no attempt was made to work out the structure of the ranges completely 

or to study the relation of the faults to one another. The major 

faults above mentioned were observed along all the streams flowing 

west into Snake River along which traverses were made, and are 

therefore indicated on the map as continuous faults.

BIGHOLE MOUNTAINS AND WYOMING RANGE.

The Bighole Mountains and Wyoming Range lie immediately 

north and east of the Snake River and Salt River ranges, from which 

they are separated by the Absaroka fault and a low depression along 

the Greys River valley and the headwaters of Elk, Palisade, Pine, 

Moody, and Canyon creeks. These ranges also were once continuous 

and have been cut nearly at right angles by Snake River. The part 

of the old range north of Snake River is known as the Bighole Mountains, and the part south of the river as the Wyoming Range. The 

geology of the range is complex and as yet little known. The rocks are 

highly folded and are broken by large faults, the exact positions of 

which have for the most part not been determined. The large thrust 

fault that extends along the east side of these ranges was mapped by 

the writer in 1906 as far north as Snake River and represents the 

northwestern extension of the Darby fault.2 Its position in the Bighole Mountains was determined only at two localities south of Victor, 

Idaho, in the vicinity of station 39 of the Hayden survey,3 and west 

of Driggs, Idaho, in the vicinity of station 42. The stratigraphic relation of the beds along the fault in these two localities, the general 

trend of the mountain range, and the numerous large springs that lie

i U. S. Geol. Survey Prof. Paper 56, p. 109, 1907; U, S. Geol. Survey Bull. 543, p. 87, 1914.

2TJ. S. Geol. Survey Bull. 543, p. 84, 1914.

3 Station numbers correspond to those used in St. John's report and are shown, on. the map (PL I).
PHOSPHATE. 37

along the fault line on the east flank of the mountains between stations 39 and 42 indicate that the fault here observed is probably the 

northward extension of the Darby fault, which lies along the east 

flank of the Wyoming Range. The stratigraphio relations of the 

beds along the east and west sides of the Darby fault are similar to 

those along the Absaroka fault; in places Carboniferous or older 

rocks on the west are brought into juxtaposition with Cretaceous 

(Colorado) rocks on the east.

TETON MOUNTAINS.

The Teton Mountains form one of the most imposing ranges in the 

Rocky Mountain region. They appear to be a large fault block upon 

which the little-disturbed Paleozoic rocks dip gently toward the west. 

The main part of the range rises with a singularly abrupt slope from 

the west side of Jackson Hole, which marks the approximate location 

of the fault along the east side of the range. It culminates in the 

rugged Grand Teton, the third highest peak in Wyoming, reaching an 

altitude of 13,747 feet. The main part of the range extends about 

due north and consists of a gentle westward-dipping monocline 

crossed at the north by a low anticline which trends northwest. 

Near the south end of the range the beds are somewhat folded and 

the main ridge is crossed by a low anticline, whose axis trends northwest, lies immediately north of station 43 of the Hayden Survey, and 

in its northwestward extension nearly parallels the Bighole Mountains. The low pass south of station 43 separates the Teton Mountains from the Bighole and Wyoming ranges and affords the only 

wagon road at the south end of the range from Teton Basin, Idaho, 

into Jackson Hole, Wyo. The rocks along the east slope of the range 

consist largely of granite, gneisses, and schists. On the west slope of 

the range the Paleozoic beds overlie the pre-Cambrian rocks and slope 

off more, gently to the broad Teton Basin, which lies between the 

Teton and Bighole mountains. The broad open plain of the Teton 

Basin is floored with nearly horizontal Tertiary or later sediments. 

The outcrops of the Mesozoic rocks are buried by extensive lava 

flows, which are in turn partly concealed by the alluvium in the 

bottoms of the basins and by widespread moraines on the plateau 

farther north.

MINERAL DEPOSITS.

PHOSPHATE. 

GENERAL FEATURES.

Rock-phosphate deposits of the same type as those in eastern Idaho 

in the vicinity of Montpelier, south of Snake River, were found by the 

writer in September, 1912, while engaged in a geologic reconnaissance
38 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

examination north of Snake River in the vicinity of the Snake River 

and Bighole mountains. It is believed that commercial deposits of 

phosphate have not heretofore been generally known in this part of 

Idaho, and no sign was observed that these beds had ever been prospected for phosphate, although in a few places they have been prospected for coal.

The rock was found as float along the outcrop of the phosphate 

bed and in place' along the central part of the Snake River Range, 

and was recognized by its physical characteristics. The more massive part of the bed, which is usually found as float, somewhat resembles a dark coarse granular limestone that may be mistaken 

on casual examination for a dark fine-grained basalt. It has an 

oolitic structure, is dark gray to black, is noticeably heavy in 

comparison with the sedimentary rocks with which it occurs, and 

on many of the weathered surfaces has a bluish-white coating. 

The oolitic structure, though constituting, one of its most definite 

features, is in places somewhat obscure; in other places it is entirely missing and the bed may be composed entirely of shalesandstone, or nonoolitic limestone, rich in phosphoric acid. By 

reason of the weaker constitution of the shaly rocks they commonly 

give way to weathering and decay at the surface, and the phosphate 

outcrop thereby becomes concealed wholly or in part, while the 

harder fragments of phosphate rock remain in the soil and are readily detected by one who is familiar with the appearance of the rock. 

In part of the area rock-phosphate float is but moderately abundant in the vicinity of the outcrops of the phosphate bed, but in 

other localities the surface is covered with numerous phosphate 

fragments.

The work done farther southeast in Idaho, where detailed examinations of the phosphate deposits have been made, and where 

sections of the phpsphate shales, especially those immediately associated with the main phosphate bed have been measured and 

studied in detail, affords a good idea of the range of phosphate 

content which may be expected within the area covered by this 

report. Two of these sections, in Georgetown Canyon, .T. 11 S., 

ft. 44 E., and in T. 8 S., R. 44 E., Idaho, have been published.1

A detailed section of the lower part of the Phosphoria formation 

was measured and sampled in 1909, exceptionally favorable conditions of exposure being found in the Georgetown district, in T. 11 

S., R. 44 E. The section of the phosphate-bearing strata in Georgetown Canyon shows the largest amount of high-grade phosphate 

rock and probably the highest average phosphoric-acid content of 

all the sections that have been examined in detail in vthe western 

phosphate fields. It represents presumably the upper limit of

i U. S. Geol. Survey Bull. 530, pp. 278, 280,1913.
PHOSPHATE. ' 39

conditions which may be found on prospecting within the area of 

this reconnaissance. The other section of the lower portion of the 

Phosphoria formation was measured and sampled about 26 miles 

north of Georgetown Canyon, in the SW. J SW. \ sec. 7, T. 8 S., ft. 

44 E. It shows the smallest amount of high-grade phosphate rock 

and also the lowest average content of phosphoric acid yet found 

in the sections measured in detail in the Idaho portion of the phosphate reserve, and will serve to illustrate the leanest conditions to 

be expected within the area of this reconnaissance.

DISTRIBUTION OF PHOSPHATE DEPOSITS BY STRUCTURAL DISTRICTS.

GENERAL CONDITIONS.

The distribution of the phosphate-bearing Phosphoria formation 

in the area examined can be inferred in part by examination of the 

accompanying map (PL I), on which the outcrops of the phosphate 

beds seen in the field are shown by lines with small crosses, and the 

inferred outcrops by light dash lines. The inferred positions in 

some parts of the field where the structure is complex and no 

examination of the phosphate beds was made are not indicated, 

although it is reasonably certain that the phosphate beds occur 

within well-defined limits, as along the east side of the Salt River and 

Snake Piver ranges, in the area between the Absaroka fault and 

the parallel fault to the west. The distribution of the Phosphoria 

formation also indicates in a general way the structure of the area. 

The phosphate beds in this area are very similar to those described 

by Gale, Richards, and Mansfield in their reports on the areas to 

the south. Only a few prospects have been opened on. the phosphate 

beds in the area examined, and all of these were opened in search of 

coal. No attempt was made in the reconnaissance examination 

to prospect the phosphate outcrops, and therefore no detailed description of the beds can be given. Samples of float and fragments 

of rock in place picked up at several places show the presence of 

high-grade material and indicate that workable beds similar to 

those prospected farther south are undoubtedly present. A preliminary study of the phosphate rock was made and samples collected in some of the localities discussed below.

CARIBOU RANGE, IDAHO.

Phosphate rock of the same character as that in Georgetown 

Canyon, Idaho, was found in the Caribou Range at several places 

on Bear Creek, Indian Creek, Fall Creek, Pritchard Creek, and Garden 

Creek. One sample of rock obtained in Bear Creek yielded 28.93 per 

cent of phosphorus pentoxide (P205), or 63.36 per cent of tricalcium 

phosphate. No other analyses have been made of this rock. The general distribution of the phosphate deposits south of Snake River is
40 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

shown on Plate I. However, as many of the formations overlying 

the phosphate beds thin greatly toward the north, and as the numerous parallel anticlines in the Caribou Range expose rocks ranging in 

age from Beckwith tov Nugget (see generalized section, p. 14), it is 

very probable that detailed geologic and stratigraphic work will 

show that phosphate beds underlie at depths less than 5,000 feet 

much of the area in the Caribou Range south and west of the phosphate outcrops shown on Plate I. The general relations of the 

Phosphoria formation to the overlying and underlying beds in the 

Caribou Range are shown in the sections measured along Tincup 

Creek, Fall Creek, and Pritchard Creek.1 The southeastward extension of the phosphate beds could not be traced, as the rocks are 

concealed beneath the gravel and alluvium along Snake and Salt 

rivers. It is probable, however, that the beds continue southeastward and connect with the phosphate beds observed in the vicinity 

of Afton Creek, on the west limb of an overturned anticline southwest of Virginia Peak, which may represent a part of the structural 

fold observed along the east side of the Caribou Range west of Snake 

River. .

SNAKE RIVER AND SALT RIVER RANGES.

GENERAL DISTRIBUTION.

Deposits of phosphate rock were found at several places from the 

north end of the Snake River Range to the south end of the Salt 

River Range, but no attempt was made to trace the outcrop of the 

phosphate beds from one locality to another. Traverses were made 

across the Snake River Range along Pine, Rainy, Elk, and Indian 

creeks and along Snake River. Examinations were also made of 

the rock along some of the divides between these streams, particularly in the vicinity of Palisade Creek and north of Pine Creek. 

The general distribution and location of the phosphate deposits in 

this range are shown on Plate I and in greater detail on the traverse 

maps of areas along the streams (figs. 2 to 6). Most of the deposits 

lie along the east side of the range, in that part of the divide lying 

immediately west of the Absaroka fault. Although the beds have 

not been traced for any great distances beyond the localities where 

they were examined, it is reasonably safe to infer from what is known 

regarding the general structure of the range that the phosphate 

beds are more or less continuous from one locality to another. Owing 

to the complexity of detail in the structure of this part of the range, 

however, the outcrop of the phosphate bed is certain to be somewhat 

irregular, and even its approximate location can not be inferred 

until a more detailed examination of the entire region is made.

i U. S. Geol. Survey Bull. 530, figs. 33, 34, and 35, 1913.
PHOSPHATE. 41

PINE CfeEEK.

The lower part of Pine Creek lies on the Snake River basalt. 

About 2 miles up Pine Creek from the point where the stream crosses 

the west boundary of the Palisade National Forest rocks of Carboniferous age are exposed. The southwestern part of the range consists chiefly of Paleozoic limestones, in which numerous horn corals 

were observed. The beds along the west side of the range dip 20° 

to 50° W., but in the vicinity of the fault east of Flemming's ranch 

the dip ranges from 50° to 70° W. Some of the beds along this ridge 

appear to be older than the Madison limestone. This fault, in which 

the downthrow is on the east, brings the Woodside formation into 

contact with Paleozoic limestone on the west. Minor faulting was 

also observed in the hills north of Flemming's ranch, but the exact 

location of the faults was not determined. Farther up the stream, 

west of the forest rangers' station, is the overthrust fault, which is 

believed to be the northwesterly extension of the Absaroka fault. 

Along this fault line quartzite of Pennsylvania!! age (Wells formation) is brought into contact with beds of Jurassic age (Beckwith 

formation) on the east. Between these two faults were noted the 

phosphate beds. The rocks in this belt are badly broken and distorted, and no attempt was made to trace the phosphate beds for 

any distance along their outcrop. It may be expected, however, 

that when these beds are mapped in detail the phosphate will be 

found at several places west of the Absaroka fault. Phosphate 

float was picked up near the middle of this belt, just east of a massive 

ledge of gray cherty limestone, but no phosphate rock was found in 

place at this locality. The general relation of the beds indicates that 

the phosphate should be present below the massive ledge. If the 

phosphate occurs in place here, there is a fault' between it and the 

phosphate outcrop to the east. The phosphate outcrop west of the 

forest ranger's station rests upon a bed of white limestone, which in 

turn rests upon quartzite beds; both limestone and quartzite belong 

to the Wells formation. A sample of phosphate obtained north of 

the road, at locality J (see PI. I), yielded 27.51 per cent phosphorus 

pentoxide (P205 ), or the equivalent of 60.1 per cent tricalcium phosphate (Ca3 (P04) 2 . The entire Phosphoria formation here is approximately 375 to 400 feet thick and contains at least one bed of phosphate about 4 feet thick. The sample collected does not represent 

the richest phosphate layer but the entire part of the bed exposed. 

The general relations of the beds as observed along the line of traverse are shown in figure 2.

In the summer of 1910 Eliot Blackwelder examined the phosphate 

beds along Pine Creek and found that the phosphate series is exposed 

in the central part of the range in a band trending approximately
42 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

N. 50° W., parallel with the range itself, Regarding these deposits

he makes the following statement:

Exposures of phosphate beds on Pine Creek are very poor, but it was possible to 

recognize a gray quartzite (Wells formation) overlain by gray limestone and about 75 

feet of phosphatic shale. A sample of the shale gives on analysis 36.8 per cent tricalcium phosphate. The expected beds of rich oolitic phosphate rock were not found 

but may well be present, although concealed by wash, soil, and tuff at the point 

examined. The phosphatic shale is overlain by the fossiliferous limestone and 

massive chert beds generally associated in this region with the phosphate beds. On 

the \rhole, the general constitution of the phosphatic series in the Pine Creek section

R.43E. R.4-4E.

Paleozoic Iir4fstone JJ!ty{£/\ V&V& ** 

\ Blue flT \ \^%1.

Fault showing. Strike and Strike and Strike and 

downthrow'n side dip vertical dip overturned dip

R.«E. R.44-E. 

FIGUEE 2. Map showing traverse along Pine Creek, Tps. 2 and 3 N., Rs. 43 and 44 E., Idaho.

is so similar to that in the Preuss Range that it is safe to expect that phosphate deposits 

of notable value will be found in the Snake River Range when it is adequately 

explored.

RAINY CREEK.

The western part of the Snake River Range along Rainy Creek consists of rocks of the same kind as those observed on Pine Creek, for the 

most part of Paleozoic age. The range here is made up of several 

parallel folds, which are broken by faults. The anticline observed 

between Rainy and Palisade creeks forms the highest point of the 

Snake River Range at this place, and its axis passes through Baldy 

Mountain in a northwesterly direction, crossing the lower portion 

of Rainy Creek. The rocks exposed on.the divide south of Rainy
PHOSPHATE, 43

Creek consists of Madison limestone and beds of Pennsylvanian (Wells) 

age. So far as known deposits of phosphate do not occur in this 

part of the range from Baldy Mountain east to the first fault shown 

on Plate I. If present they occupy the crests of the ridges and 

constitute remnants that have not yet been removed by erosion from 

some of the closely folded synclines.

The first prominent fault observed on going up Rainy Creek-lies 

just east of the canyon on the south fork of the creek and may represent the southeasterly continuation of the westernmost fault observed 

on Pine Creek. The fault brings the Ankareh shale -on the east into 

contact with the qiiartzite of the Wells formation on the west. The 

downthrow is on the east and is somewhat greater than on Pine Creek, 

although the general relations'are the same. Farther up the stream

R.4*E. R.4-5 E.

Paleozoic limestone Unsurveyed

R.44-E.

FIGURE 3. Map showing traverse along Rainy Creek, T. 2 N., Rs. 44 and 45 E., Idaho.

the Absaroka overthrust brings the Beckwith formation into contact 

with the Wells formation on the west. The phosphate occurs between 

these two faults, immediately beneath a massive ledge of Rex chert 

50 feet or more thick and above a bed of white limestone, which is 

the upper part of the Wells formation. A sample of phosphate 

rock was gathered at this locality (H, PL I) from the Phosphoria 

formation, which is about 375 feet thick. A phosphate bed 3£ feet 

thick yielded 31.69 per cent phosphorus pentoxide (P205), or 69.4 

percent tricalcium phosphate (Ca3 (P04) 2 . A short distance east of 

the fault lies the contact between the Beckwith formation and the 

Twin Creek limestone, both of which strike northwest and dip 30°-35° 

SW. The general relations observed along Rainy Creek are shown 

in figure 3.
44 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Phosphate deposits are also exposed on the north fork of Rainy 

Creek in much the same relations as on the south fork. H. Corbet, 

of Irwin, Idaho, states that a coal claim has been staked on these 

deposits and attempts have been made to develop it. Mr. Corbet 

was primarily interested to know if the material was coal, as he 

wished to determine whether or not a coal supply for Swan Valley 

could be obtained at this place. He furnished a sample of rock 

taken from the prospect on the North Fork (I, PL I), which yielded 

17.08 per cent phosphorus pentoxide (P205 ), or 37.4 per cent tricalcium phosphate (Ca3 (P04) 2 ), and gave evidence of organic matter. 

The rock consists of a black carbonaceous shale such as is often found 

associated with the richer phosphate beds.

PALISADE CREEK.

Similar phosphate rock occurs between the two faults on Palisade 

Creek above the upper lake, which likewise has been prospected for 

coal. A sample of phosphate rock from this locality (G, PL I) 

reported to show the physical characteristics of coal was analyzed 

and yielded 12.69 per cent phosphorus pentoxide (P205), or 27.8 per 

cent tricalcium phosphate (Ca3 (PO4) 2), and gave good evidence of 

organic matter.

Structural observations on the divide between Rainy and Palisade 

creeks east of the anticline that passes through Baldy Mountain and 

west of the first fault shown on Rainy Creek show that immediately 

east of Baldy Mountain is a low syncline in Carboniferous rocks whose 

axis strikes northwest. Immediately east of this low syncline is a 

gently folded anticline whose axis strikes N. 60° W. and exposes 

along its crest beds of Pennsylvanian age, a little lower stratigraphically than the beds exposed in the syncline. Farther east is another 

shallow syncline, to the east of which is a second sharply folded 

anticline whose east limb is cut by the fault. The west limb of-the 

anticline strikes N. 60° W. and dips 30° SW.; the east limb strikes 

N. 40° W. and dips 70° NE. The beds exposed along the divide 

between Rainy and Palisade creeks appear, to consist chiefly of the 

Madison limestone and the overlying Wells formation. At no place 

west of the fault in these two synclines were phosphate beds or the 

Phosphoria formation seen. In the block between the two faults, 

the eastern of which is the Absaroka, the Phosphoria formation is 

present and deposits of phosphate are known to occur. Similar 

deposits occur east of the Absaroka fault but lie at a considerable 

depth below the surface, though the exact depth can not be determined until a detailed stratigraphic study of the region has been made.
PHOSPHATE.

ELK 6RBBK.

45

No deposits of phosphate rock were seen near the line of traverse 

along Elk Creek. The main part of the Snake River Range is composed of rock of Paleozoic age. The rocks in this vicinity are highly 

folded and are broken by faults, the exact position of which has not 

been ascertained except along the line of traverse. Two main anticlinal folds trending in a northwesterly direction cut across Elk Creek, 

and with these folds are associated numerous minor folds and flexures. On the upper part of Elk Creek the same fault relations were 

observed as along Rainy and Pine creeks, but here the streams have 

cut through the phosphate beds and are now intrenched in rocks of the

R.46E. R.II8W.

FIGURE 4. Map showing traverse along Elk Creek, T. 1S., R. 46 E., Idaho, and T. 39 N., R. 118 W.,TVyo.

Wells and underlying formations. In the area between the two faults 

the phosphate-bearing beds are present in the ridges both north and 

south of the stream. From the traverse along the valley it appears 

that phosphate deposits occur near the crests of some of the ridges, 

but no attempt was made to trace the horizon or examine the separate 

hills to determine the presence and thickness of the phosphate beds. 

The general relations and the attitude of the phosphate bed along 

Elk Creek are shown in figure 4.

, From the examination made in this vicinity it is apparent that no 

phosphate deposits occur in the Snake River Range west of the western fault shown in figure 4, as this part of the range consists of rocks 

older than the phosphate formation. The western flank of the range
46 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

may terminate abruptly along a fault or it may represent the eastern 

limb of a closely folded syncline, but in either case the phosphate 

beds are not present between Snake River and the fault. Owing to 

the heavy cover of gravel, recent conglomerates, and lava flows 

that masks the underlying Paleozoic rock along the west flank of the 

range, the structure has not been satisfactorily determined.

INDIAN CHEEK. 1

A foot-paced traverse was made on both the North and South forks 

of Indian Creek. The structure of the west flank of the Snake River 

Range in this vicinity is very similar to that on Elk Creek, in that the 

older Paleozoic rocks are partly concealed by gravel and nearly horizontal conglomerate beds that dip gently away from the mountains. 

It appears, however, that the west base of the main range coincides 

approximately with the synclinal axis in the Paleozoic rocks that cross 

Indian Creek just below the forks. The main part of the Snake River 

Range in this vicinity consists of Paleozoic rocks in every way similar to those observed on Elk, Rainy, and Pine creeks. The main anticline of the range crosses both the North and South forks of Indian 

Creek and is cut out by a fault a short distance south of the South 

Fork. This anticline probably represents the southward extension 

of the anticline that passes through Baldy Mountain east of Irwin 

and is the same as that observed on Palisade and Elk creeks. All 

the rocks west of the fault shown in the accompanying map (fig. 5) 

are older than the Phosphoria formation, and no phosphate deposits 

are known to occur in this part of the range. Beds of Pennsylvanian 

(Wells) age are exposed east of the fault

The sandstones of the Wells formation are overlain by the Phosphoria formation, which in turn is overlain by the Woodside and 

Thaynes formations. The traverse on the South Fork of Indian 

Creek was not carried far enough up the stream to encounter the 

phosphate beds, but it is apparent from the examination made that 

they are present on the upper part of this stream. On the North 

Fork of Indian Creek the phosphate bed was encountered immediately beneath the massive Rex chert member and immediately above 

the limestone member at the top of the Wells formation. The Phosphoria formation here is approximately 400 feet thick, and the phosphatic series about 75 feet thick. The rich phosphate bed was not 

measured but is believed to be from 3 to 4 feet in thickness. A 

sample collected from the phosphate bed on the north side of the 

creek (A, PL I) yielded 32.85 per cent phosphorus pentoxide (P205 ), 

or 71.78 per cent tricalcium phosphate (Ca3 (P04) 2).

The general relations of the Phosphoria formation to the overlying 

and underlying formations are shown in figure 5.

1 This stream should not be confused with the Indian Creek in the Caribou Range.
PHOSPHATE. 47

Similar relations to those observed here may be expected along the 

upper part of South Fork of Indian Creek. On the divide between 

the two forks the phosphate deposits extend much farther west and 

may extend to the fault contact. The high ridge to the east is apparently underlain by the phosphate bed.

SNAKE RIVER.

The structural conditions along the west base of the Snake River 

Range on Snake River are similar to those observed on the streams 

to the north. The Paleozoic beds are closely folded and compressed, 

and in places they appear to be overturned. At the mouth of the

R.46E; R.II8W.

R.46 E. R.I 18 W.

Strike and dip ' Anticline Syncline

FIGUKE 5. Map showing traverse along Indian Creek, T. 2 S., R. 46 E., Idaho, and T. 38 N., R. 118 W.,

Wyo.

Snake River canyon the beds show clearly in wavy lines along bedding planes the effect of the compression strain. The anticlinal axis 

observed on Indian Creek is not present on Snake River, as it is cut 

out by the western fault. The Paleozoic beds west of the fault are 

the same as those on Indian Creek but here represent only the west 

limb of the anticline. The structure on Snake River in the belt 

between the western fault and the Absaroka fault is more complex 

than that observed on Indian Creek, as there are here three distinct 

anticlines trending approximately north. In this belt the phosphate 

deposits occur well up on the higher hills, there being no deposits 

of phosphate along the line of traverse, as Snake River has cut through
48 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

the Phosphoria formation and exposes older beds throughout its 

course from the lower end of the canyon up to the Absaroka fault. 

On the north side of Snake River beds of the Phosphoria formation 

were seen in the higher hills and probably represent the southward 

extension of the beds observed along Indian Creek. It is not known 

whether the phosphate beds occur in the hills between Greys River 

and Snake River on the south side of the Snake. East of the Absaroka fault and west of the Wyoming Range the Phosphoria beds lie at a 

great depth, as in this area the surface exposures consist of beds of 

Cretaceous age. The outcrop of the Phosphoria formation along the 

west side of the Wyoming Range is described on pages 23-24. The

R.II6W.

R.II7W.

5 6 MILES

Fault showing 

downthrown side

Strike' and dip Strike and overturned 

dip

Synclme

FIGURE 6.-Map showing traverse along Snake Eiver canyon, Tps. 37 and 38 N. ; Rs. 116,117, and 118 W.f

Wyo.

structure between the Absaroka fault and the Wyoming Range, so 

far as known, is shown in figure 6.

On this part of Snake River at least one pronounced anticline and 

one syncline that trend about north cross the river at nearly right 

angles. It is not known what beds are exposed along their axes in 

the region of Snake River. If the beds are closely folded, as they 

are in the vicinity of Little Greys River, beds of Jurassic age probably crop out along the crest of the anticline and beds of Cretaceous 

age along the axis of the syncline. The coal-bearing Frontier or 

Bear River formation may be present in the syncline as coal has been
PHOSPHATE. 49

reported in this belt on Snake River. No examination was made 

of the beds along Snake River between the Absaroka fault and the 

mouth of Bailey Creek, and it is not known what bids are exposed 

at the surface.

In the course of this reconnaissance examination no observations 

were made south of Snake River, but it is known from earlier work 

in this region that the phosphate deposits occur at several points 

farther south. South of Virginia Peak the central part of the range 

consists of a syncline along which beds of Triassic age are exposed. 

The Salt River Range is terminated on the east by the Absaroka 

fault, which in this locality brings Mississippian limestone into contact with Cretaceous beds. The western part of the range consists 

of a northwestward-trending anticline, in places overturned. The 

phosphate beds crop out along the west flank of this anticline and 

along both limbs of the syncline in the central part of the range. 

Toward the north along both anticline and syncline older beds appear 

at the surface, and west and north of Virginia Peak all the phosphate beds have been eroded except possibly along the west flank 

of the anticline, where they may be concealed by the gravel and 

alluvium along Salt River. Whether or not the northwestwardtrending anticline observed in this part of the Salt River Range is 

the southeastern continuation of the anticline observed near the 

mouths of McCoy and Bear creeks, east of the Caribou Range, was 

not determined.

As the Paleozoic formations run nearly parallel to the Salt River 

Range it is probable that south of Virginia Peak the phosphate deposits are found generally along the range, usually well up toward 

its crest, and there is reason to believe that they are not subject to 

great variations in richness along the outcrop. In 1910 C. L. Breger 

recognized the phosphate beds in the canyon of Swift Creek east of 

Afton, Wyo. He found at the base of the phosphate beds about 

42 feet of gray limestone, overlain by 40 to 78 feet of soft shaly beds, 

including phosphate rock, overlain in turn by more than 100 feet of 

massive to thin-bedded chert. It is believed that there are two 

phosphate beds in the shaly strata here, the lower one at the base 

and the upper one about 45,feet above the base. The thickness of 

either is still unknown, but pieces of the float from the upper bed, 

consisting of massive black oolite, yielded on analysis 67.4 per cent 

of tricalcium phosphate. Since the preparation of this report a 

reconnaissance examination for phosphate in the Salt River Range 

has been made by G. R. Mansfield.1

1 Mansfield, G. R., A reconnaissance for phosphate in the Salt River Range, Wyo.: U. S. Geol. Survey 

Bull. 620, pp. 331-347, 1915.

52756° 18 Bull. 680- 4
50 PHOSPHATE AND COAL IN IDAHO AND WYOMING. 

BIQHOLE MOUNTAINS AND WYOMING RANGE.

GENERAL FEATURES.

The Bighole Mountains and Wyoming Range lie immediately 

northeast of the Snake River and Salt River ranges and are, like 

them, terminated on the east by a pronounced fault. Deposits of 

phosphate have been observed at several places in these ranges, 

for the most part on the west side of the mountains, whereas in the 

Snake River Range the deposits lie on the east flank of the main 

mountain range. Phosphate outcrops were observed at several 

localities on the west slope of the Wyoming Range southeast of 

Snake River. On Snake River in the vicinity of Counts's ranch, 

several miles below the mouth of Hoback River, the Phosphoria 

formation and the overlying and underlying rocks were noted on 

the southwest flank of the range. In the Bighole Mountains the 

same beds were observed in the vicinity of station 39, south of 

Victor, Idaho, and on the west flank of the range in the vicinity of 

stations 40 and 42, but were not seen in the vicinity of the headwaters of Pine Creek, where the road crosses the divide from Teton 

Basin to Conant Valley on Snake River. It is believed that the 

phosphate beds here are cut out by the fault, as Cretaceous beds 

occupy the crest of the ridge. The phosphate outcrop was not 

found in the Bighole Mountains west of Victor and Driggs, Idaho, 

as the 8-inch cover of snow concealed it from view. From the 

structure and from the overlying and underlying beds it appears 

that deposits of phosphate occur in this part of the range, although 

locally, as in the upper part of Pine Creek, the phosphate bed may 

lie at a considerable depth below the surface. Although the beds 

have not been traced for any distance beyond the locality where 

they were examined, it is reasonable to assume that they are present 

in this range from the headwaters of Canyon Creek, west of station 

42, southeastward to Snake River.

WYOMING RANGE SOUTHEAST OF SNAKE RIVER, IN THE VICINITY OF BAILEY CREEK.

In the summer of 1906, while the writer was mapping the geology 

southeast of Snake River, he recognized the Park City beds, which 

include the Phosphoria formation, on the west flank of the Wyoming 

Range and traced them from the southern part of Wyoming northward to Snake River. Phosphate samples were obtained at several 

localities toward the south, but none were collected in the vicinity 

of Snake River. The Phosphoria formation, including the phosphate 

bed, was not mapped separately at this time but grouped with the 

overlying Woodside and Thaynes formations. It is reasonably certain that the bed of phosphate occurs in this part of the range and 

overlies the Pennsylvanian sandstone and limestone that form the 

west slope of the range southeast of Snake River.
PHOSPHATE. 51 

WYOMING RANGE IN THE VICINITY OF SNAKE RIVER.

In the vicinity of Counts's ranch, on the opposite bank of Snake 

River in the NE. £ sec. 32, T. 39 N., R. 116 W., there is a good 

exposure of the phosphate rock. The black material has long been 

supposed to be coal, and the deposit has been considered by the 

inhabitants as a possible source of coal for local use. Here, as at 

other places farther south, the deposit consists of approximately 60 

feet of shale representing the phosphate rock. The richer phosphate 

beds alternate with black phosphate, shale, and limestone that carry 

a small amount of tricalcium phosphate. These phosphate beds are 

not the northward extension of the beds observed on the west flank 

of the range east of Bailey Creek but lie on the east side of the 

Darby fault. The northward extension of the Bailey Creek phosphate beds on the west side of the range passes beneath the gravel 

along Snake River and probably lies some distance west of the exposures at Counts's ranch. The beds on Snake River east of the 

Darby fault in the vicinity of Counts's ranch crop out in a closely 

folded anticline that crosses Snake River in a southerly direction 

and is broken by one or more minor faults. The structure of the 

range is much more complex in this vicinity than it is farther south, 

and considerable time would be required to work out the details 

and trace the phosphate outcrop northward to the vicinity of station 

39, southwest of Victor, Idaho. Eliot Blackwelder visited the Snake 

River locality in 1910 and measured the following detailed section, 

which represents fairly well the Phosphoria formation in this part 

of the range:

Section of phosphatic beds in the northwest bank of Snake River opposite Counts's ranch, 

in sec: 32, T. 39 N., R. 116 W., Wyo.

Top overlain unconformably by Tertiary conglomerate. Ft. in. 

Shale and limestone, gray-buff to brown, with thin black phos- 

. phatic seams here and there............................... 20

Phosphate rock, brown and nodular (21.2 per cent tricalcium

phosphate).............................................. 2 6

Phosphate rock, black, soft, and shaly (random sample, 68.5

per cent tricalcium phosphate)............................. 9 .==,

Chert, dark gray............................................ 12

Shale, black and probably phosphatic....................... 4

Chert and Beams of limestone, passing gradually upward into

cherty limestone with black shale partings................. 33

Limestone, earthy buff to gray, with black chert nodules...... 20

Sandstone, soft and white, with thin beds of gray chert....... 26

Sandstone, fine, white, and very soft......................... 6

Limestone, pearl-gray, argillaceous.......................... 22

Phosphate rock, black and oolitic............................ 2$

Chert, massive, gray....................................... 6
52 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Alternating thin beds of soft oolitic phosphate rock and hard Ft. in. 

black limestone (probably about 20 per cent tricalcium 

phosphate).............................................. 5 10

Massive brown phosphate rock (66.3 per cent tricalcium phosphate) .................................................. 2 5

Limestone, brittle, black.................................... 1

Phosphate rock, soft, black, granular (20 to 30 per cent phosphate). ................................................. 3

Limestone," brittle, black.................................... 2 6

Phosphate rock, soft and shaly (29.6 per cent phosphate)...... 4 6

Limestone, brittle, black.................................... 2

Phosphate, black, shaly, and granular, with lenses of black 

limestone (average of entire bed, '20.3 per cent tricalcium 

phosphate).............................................. 12-

Limestone, brittle, black................................... 1 3$

Phosphate rock, soft, shaly, and granular, with lenses of black 

limestone (average of entire bed, 31.2 per cent tricalcium 

phosphate).............................................. 12

Limestone, hard, dark gray................................. 9

Sandstone, soft, argillaceous, gray........................... 8

Shale and limestone, smoky gray to buff..................... 22

Quartzite, white to buff (Wells formation)...:................ 47

BIGHOLE MOUNTAINS SOUTH OP VICTOR, IDAHO.

In the vicinity of station 39, in T. 2 N., R. 45 E., south of Victor, 

Idaho, the series of rocks exposed is the same as that observed east 

of Bailey Creek in the Wyoming Range, south of Snake River. 

(See fig. 6, p. 48.) The beds have practically the same relations 

and are terminated on the northeast by a pronounced fault, believed 

to be the northward extension of the Darby fault, that separates 

them from the beds along the west flank of the Teton Mountains, 

in the south end of Teton Basin. The oldest beds exposed in the 

vicinity of station 39 lie near the east base of the Bighole Mountains, where Carboniferous rocks, probably of Pennsylvanian age, 

occur. The Carboniferous rocks are exposed for a distance of several 

miles in a northwesterly direction along the fault contact, but the 

outcrop is cut out entirely by the fault before the beds pass beneath 

the gravels and valley fill along the west'side of Teton Basin, only 

to reappear several miles to the northwest, in Tps. 4 and 5 N., R. 

44 E., where they form a pronounced range of' hills facing Teton 

Basin. The summit of the hill on which station 39 is located consists of Nugget sandstone that strikes N. 10° W. and dips 45° SW. 

This sandstone is overlain by a considerable thickness of dark-drab 

limestone and shaly beds of the Twin Creek formation. These beds 

may represent the eastern extension of the Twin Creek limestone 

observed on the upper part of Rainy Creek, as the strike and dip 

are in the same direction. It is very probable, however, that there 

is another anticlinal fold between these two localities. No examina-
PHOSPHATE. 53

tion was made of the intervening area, and the structure in this part 

of the range may be more complex than it appears from a distance. 

It is not probable, however, that the phosphate beds are exposed at 

the surface along a line joining these two localities. The Phosphoria 

formation and the overlying formations from the Phosphoria to the 

Nugget sandstone appear to be present in their normal position on 

top of the Carboniferous rock between station 39 and the crest of 

the range northeast of station 40, west of the Darby fault. As the 

ground was covered by a heavy fall of snow at the time of the 

writer's visit neither the phosphate bed nor any fragments of phosphate float were found, but the general structure of the region and 

the presence of the accompanying formations indicate that the 

Phosphoria formation occurs here and can no doubt be readily found 

under favorable conditions.

NORTH EtfD 01? BIGHOLE MOUNTAINS.

Northwest of station 39 along the strike of the beds all the formations overlying the hard pink sandstone (Nugget sandstone) 

apparently extend to stations 40 and 42 and beyond. There 

appear to be some minor displacements and secondary folds, but 

on the whole the structure is comparatively simple. Cretaceous 

beds form the main part of the divide where the road from Victor, 

Idaho, to the Snake River valley crosses the range. These beds contain, coal and are believed to be of Bear River and Benton (Colorado) 

age and equivalent to the Bear River and Frontier coals in western 

Wyoming, south of Snake River. Whether or not the coals are 

continuous along this belt or whether the Frontier formation is 

present only in places between the Darby and Absaroka faults from 

Snake River northward to Canyon Creek, where the older beds are 

concealed beneath the lava flow, or whether the coal beds in this 

part of the range all belong to the Bear River formation, was not 

determined. Much of this area has never been mapped geologically, 

. and coal prospecting has been restricted largely to the vicinity of 

Pine Creek, where considerable work has been done during 1911 and 

1912 with more or less success.

The Carboniferous beds and those immediately overlying them 

appear to be cut out by the fault a short distance northwest of 

station 39, or they may have been eroded and lie buried beneath 

the gravels along Pine Creek, on the west side of Teton Basin. More 

detailed work will no doubt show what has become of these beds in 

the region of Pine Creek southwest of Victor. The entire series of 

Carboniferous rocks and overlying beds reappear north of station 40 

and are apparently continuous from this locality northwestward to 

station 42 and beyond, where they pass beneath the lava-covered 

plains along the headwaters of Canyon Creek. The oldest beds in
54 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

the section occur north of station 40, and it is believed that these 

beds are older than Mississippian. The crest of the ridge at station 

42 consists of Madison limestone that strikes northwest and dips 

for the most part southwest. A little farther northeast, along the 

fault escarpment at the northeast extremity of the ridge, occur 

quartzites of Pennsylvanian age that strike north and dip 10°-65° E. 

Minor folding and faulting were observed along this part of the range, 

but time was not available to work out the structure in detail. 

Southwest of station 42 the beds strike N. 40° W. and dip 30° SW., 

and the entire series of beds overlying the Carboniferous are as fully 

developed in this vicinity as they are southwest of stations 39 and 40. 

The crest of the hills on which station 40 is located, like that at 

station 39, consists of hard pale-red or pink sandstone, which in 

places is almost quartzitic. For a considerable distance this ridge 

forms the main divide between Snake River and Teton Basin and is 

capped by this heavy massive quartzite or sandstone, which is probably equivalent to the Nugget sandstone of western Wyoming and 

eastern Idaho. Between this sandstone and the uppermost Carboniferous beds, composed of drab and gray cherty limestone, 

occurs a series of deep-red arenaceous shales and sandstones, with 

associated gray and drab limestone, which form a wide belt of 

brilliant-colored exposures in the northeast face of the ridge at 

station 40 and can be seen from a distance passing to the southwest 

of station 42 and beyond until they disappear beneath the lava 

plains. At the base of this series, overlying the Pennsylvanian beds, 

is the Phosphoria formation. Owing to the heavy cover of snow it 

was not practicable to try to locate the phosphate bed or to measure 

the thickness. From what is known of the geology and structure of 

this part of the range and .from the reported prospects along the 

headwaters of Canyon Creek, where the continuity of the phosphate 

bed has been shown, it seems reasonably certain that the phosphate 

deposits are present throughout this part of the Bighole Mountains. 

St. John,1 in his report on the "Pierres Hole" (Bighole) Mountains, 

gives a section through station 40 and a profile showing the relations 

of the beds to one another in that part of the range along a line that 

passes through stations 40 and 42. The entire section described by 

him has not been examined, but it appears that the 2,000 feet of 

beds in his section numbered from 1 to 14 represent the Carboniferous 

and underlying beds. It is reasonably certain that they include 

beds of Pennsylvanian and Madison (lower Mississippian) age, and 

they may include some older beds at the base. The 2,500 feet of 

beds numbered from 15 to 26 represent the Phosphoria formation, 

Woodside formation, Thaynes limestone, Ankareh shaley and Nugget 

 sandstone. The 1,200 feet of beds numbered from 27 to 34 probably

1 St. John, Orestes, U. S. Geog. and Geol. Survey Terr. Eleventh Ann. Kept., pp. 425,427,1879.
PHOSPHATE. 55

represent the Twin Creek limestone. The 540 feet of beds numbered 

. t from'35 to 38 represent part of the Beckwith formation. It appears 

from his descriptions that this section contains no part of the overlying Cretaceous beds.

Northeast of station 42 a pronounced thrust fault, which is believed 

to be the northwestward extension of the Darby fault, brings the 

Carboniferous beds into contact with the Cretaceous and underlying 

beds on the east. The Cretaceous beds east of the fault belong to the 

Frontier formation and are of Benton age. In a hard ledge of sandstone on Packsaddle Creek, in the SW. £ SW. \ sec. 24, T. 5 N., 

E,. 43 E., the writer found numerous fragments and several complete 

casts of Inoceramus labiatus, Inoceramus erectus, and other associated 

Frontier species, which place these beds and their associated coals 

in the Frontier formation. Several beds of coal occur in this formation and are discussed in more detail under the heading "Coal."

The Frontier beds near the fault line strike N. 20°-35° W. and dip 

from 50° S. 70° W. to 60° S. 65° W. Toward the east at right angles 

to the beds the dip flattens slightly as far as the ridge in sees. 19, 30, 

and 32, T. 5 N., R. 44 E., which is composed of Jurassic beds. This 

ridge trends northwest and the beds dip 54° SW. East of the ridge 

the Frontier formation observed on the west side is again encountered. 

A few coal prospects have been opened in these beds, but they have 

not been thoroughly prospected. The beds strike north and dip 

10° W.

The occurrence of Frontier coals both east and west of the Jurassic 

ridge, all of which dip toward the west, indicates an overturned anticline or a fault along the east side of the Jurassic ridge, which duplicates the Cretaceous beds. The structure is somewhat complex, and 

more detailed work is required to determine accurately the relation 

of the coal beds on the east and west sides. The overturning of the 

anticline, if it occurred, was probably due to the large thrust movement from the west. East of the anticline is an overturned synclirie, 

east of which in turn is another low, flat anticline that probably 

represents the western margin of the broad, open synclinal trough 

of the Teton Basin. The Teton Basin syncline and the low anticline 

along its western margin are for the most part concealed beneath 

Tertiary lavas. The writer's observations in this part of the Bighole 

Mountains, made during a brief reconnaissance when much of the 

ground was covered by snow, agree fairly well with the results 

reported by St. John. 1 They do not, however, confirm his conclusions regarding the fault east of station 42, for this fault is thought 

to be a thrust fault instead of a normal fault as shown in his profile, 

which passes through station 42 across the north end of the range.

i St. John, Orestes, op. cit., pp. 430, 432, pi. 38.
56 PH6SPHATE AND COAL IN IDAHO AND WYOMING.

No. 1 of St. John's section through station 42 represents the Tertiary 

lava that conceals the underlying formations in the Teton Basin. 

These beds dip about 15° E. Beds 2 to 4 represent in part the Frontier formation and the underlying Cretaceous rocks. Beds 5 to 12 

represent the Jurassic beds exposed in a prominent ridge east of 

station 42 and are chiefly of Beckwith age, although some Twin Creek 

limestone is exposed in parts of the ridge. Beds 5 and 12 are believed 

to represent the same s'tratigraphic ledge. Beds 13 to 17 represent 

Cretaceous beds lying between the Jurassic ridge and the Carboniferous beds west of the Darby fault and include the Frontier formation. 

Bed 18 represents the Pennsylvanian and the Madison limestone 

west of the fault that forms the eastward-facing scarp of the main 

-mountain range. The Jurassic ridge east of station 42 and the associated Cretaceous beds both east and west of the ridge disappear 

beneath the Tertiary lavas within a short distance to the north, but 

toward the southeast they extend to the western border of Teton 

Basin, where they have been eroded and are now covered by recent 

deposits. Coal beds of the Frontier formation may also occur 

beneath a large part of the Teton Basin east of the easternmost 

anticline observed, but no exposures of coal were seen on the east 

side of the Jurassic ridge east of the exposures on Horseshoe and 

Packsaddle creeks.

. Although the phosphate beds probably underlie all of the Teton 

Basin syncline from the Darby fault east to the phosphate exposures 

along the west flank of the Teton Mountains east of Driggs and Victor, 

Idaho, no exposures of these beds were .seen between the Darby 

fault and the east side of Teton Basin. If present these beds lie at 

a considerable depth below the surface.

TETON MOUNTAINS.

The Phosphoria formation is exposed in the Teton Mountains only 

near the south end along the western flank of the range. The east 

side of the range is bounded by a pronounced fault, and all the beds 

composing the range west of the fault to the west slope are older 

than the Phosphoria formation. Along the west slope of the range, 

where the Phosphoria formation crops out, the phosphate beds are 

poorly exposed. Farther north the lower slopes of the range are 

covered by gently westward-sloping sheets of Tertiary lava that conceal the phosphate and underlying beds. Phosphate deposits were 

observed by the writer in 1911 along the west slope of the range east 

of ^Victor, Idaho, between Moose and Fox creeks, but no section of 

the bed was measured. Eliot Blackwelder, in 1910 and 1912, 

examined the beds from the vicinity of Alta, Wyo., where they pass 

beneath the lava cover, southward to the south .end of the Teton 

Basin. At the south end, where the Teton Mountains merge with
PHOSPHATE. 57

the.Bighole Mountains, the phosphate beds that underlie Teton 

Basin become folded in a sharp, compressed syncline between the 

Teton Mountains on the east and the beds west of the Darby fault 

northeast of station 39. The outcrop of the phosphate bed along . 

this part of the range is shown on Plate I. Near the mouth of Coal 

Creek, in T. 41 N., R. 118 W., Wyo., an old coal prospect dump 

shows a soft black material which represents the location of the 

phosphate bed. The tunnel was dug about 25 .years ago on the 

supposition that a valuable bed of coal could be opened at this place. . 

The prospect is now badly caved, and a good section of the bed can 

not be measured without considerable prospecting or digging. 

Blackwelder, who Visited the prospect in 1910, states that the phosphate bed appears to be several feet thick and ranges from soft 

black oolite to earthy phosphate rock. The oolite yields 52.2 p'er 

cent of tricalcium phosphate, and a general sample of all the material 

on the dump yields 20.8 per cent of tricalcium phosphate.

In 1911 John duff, of Victor, Idaho, was opening a prospect in 

the vicinity of sec. 15, T. 41 N., R. 118 W., with the expectation of 

finding a local supply of coal for Victor and the Teton Basin. He 

reports that the beds here strike northwest and dip 45° SW., and that 

the supposed coal bed is 5 feet thick. A sample of this material 

sent in for analysis yielded a trace of phosphorus pentoxide (P205 ) 

and showed evidence of organic matter supposed to be coal. From 

the sample it appears that the prospect was opened on the phosphatic series and represents the carbonaceous shale accompanying the 

main phosphate bed, which in places yields from 50 to 80 per cent 

tricalcium phosphate.

The only section of the phosphate beds available along the west 

flank of the Teton Mountains was measured by Eliot Blackwelder, 

in 1912, while mapping a part of the Grand Teton quandrangle. 

Most of the Phosphoria formation, the top of which has been in part 

removed by erosion and the base of which indicates a slightly eroded 

contact, is well exposed on the slope of the ravine between Darby 

and Fox creeks in what will probably be when surveyed sec. 29, T. 

43 N., R. 188 W.

Section of Phosphoria formation on Darby Creek, Wyo.

[Measured by Eliot Blackwelder.]

Feet.

Brown, cherty sandstones with tubular bodies of chert............ 30+ , Massive friable gray dolomite with chert nodules and traces of ' 

marine fossils................................................ 19

White soft sandstone. ............................................ 1. 5

Chiefly thin-bedded yellow and pink dolomite, chert and sandstone; concealed in part. ..................................... 21

Gray to buff shaly dolomite and chert. .......................... 8

Yellow shale and argillaceous dolomite.......................... 7. 5
58 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Massive gray oolitic phosphate rock, containing 68.2 per cent tri- Feet. 

calcium phosphate........................................... 0. 8 ^

Olive-gray chert. ...... ^....................................... 1. 9

Gray oolitic phosphate rock, containing 73.2 per cent tricalcium 

phosphate..:................................................. .9 - -

Massive gray chert with dolomite................................. 4

Fine-grained oolitic phosphate rock, containing 71.8 tricalcium 

phosphate.................................................. J .6 *

Dense gray dolomite............................................ .3

Pisolitic blue-black phosphate rock, containing 72.9 per cent tricalcium phosphate; white selected coarse pisolitic layer contains 75.9 per cent........................................... . 1. 5 _^,

Massive gray chert. ........ ......................:.............. 1.1

Gray oolitic phosphate rock, containing 76.4 per cent tricalcium 

phosphate................................................... .8 ,__^

Dark-gray sandy phosphatic breccia, at the base of which is a 

slightly eroded contact........................................ .5

99.4

JACKSON HOLE AND VICINITY.

No detailed examination has been made of the area in the vicinity 

of Jackson, Wyo., between the Teton, Hoback, and Gros Ventre 

mountains. Phosphate deposits are known to occur on the north and 

south sides of the Gros Ventre Mountains and at several places along 

the Hoback Range. The geology, structure, and phosphate deposits 

of these ranges are discussed more fully in previous publications.1 

The structure in the vicinity of Jackson is complex and is as yet only 

partly understood, owing to the widespread cover of the older rocks 

by Tertiary beds and alluvium along Snake River. For this reason 

exposures of phosphate rock are meager, and a detailed examination 

is necessary to determine the structure and distribution of the phosphate beds in this locality. Although phosphate exposures have not 

been found, it is known that phosphate occurs in this area. In sees. 

17, 18, 19, and 33, T. 41 N., R. 116 W., fragments of phosphate rock 

were found in such relations as to indicate that the phosphate bed 

lies immediately beneath the surface. In the NW. \ sec. 33 Eliot 

Blackwelder in 1911 found in the soil and debris at a definite horizon 

just above the Pennsylvanian sandstone abundant quantities of 

weathered black oolitic phosphate rock, which occurs near the base 

of the Phosphoria formation. Samples of this float on analysis 

yielded 61.3 per cent of tricalcium phosphate. Outside of these two 

localities and the area south of Jackson, at the north end of the 

Hoback Range, no deposits of phosphate are known to occur in the 

area east of Snake River and north of the Wyoming Range.

i U. S. Geol. Survey Bull. 470, pp. 452-481, 1911; Bull. 543, 1914.
PHOSPHATE. 59 

DEVELOPMENT OF PHOSPHATE DEPOSITS.

The phosphate industry in the Rocky Mountain region has made 

progress slowly. In 1913 approximately 5,919 long tons of phosphate rock was mined, of which 5,053 tons was sold for $18,167, 

an average price of $3.57 a ton. This production was less than 0.5 

per cent of the entire phosphate production of the United States in 

1913. In 1916 the proportion was only 0.08 per cent. Part of this 

lack of progress may be attributed to the fact that some of the early 

properties have been involved in litigation, part to the high cost of 

transporting the phosphate to localities where it is needed for depleted 

soils, and part to the fact that as yet comparatively few agriculturists 

fully appreciate the increased production possible by the use of 

phosphate fertilizer.

Thus far phosphate rock has been shipped in the West for commercial use from only a few localities in the West. All the localities 

at which small mines have been opened and from which rock has been 

shipped are in the Bear Lake region, in southeastern Idaho, northeastern Utah, and western Wyoming, where the deposits were first 

discovered. Slight as the development has been in these older 

localities, there is still a marked contrast between them and the area 

described in this report, for in this area the phosphate deposits have 

received practically no attention from the prospector, and their very 

existence seems to be unknown to him or to the inhabitants. What 

little prospecting has been done along the phosphate outcrop was 

undertaken with the idea of opening coal mines from.' which a supply 

of coal could be obtained for local use. The phosphate beds have 

been prospected in Wyoming for coal on Snake River south of Jackson Hole and at the mouth of Coal Creek, near the southeast end of 

Teton Basin; and in Idaho'on Patterson- Creek, on North Fork of 

Rainy Creek and Palisade Creek east of Swan Basin, in Burns Canyon, and on the headwaters of Canyon Creek, in the Bighole Mountains. Although coal has been reported from these beds at many 

places in the mountains north of Snake River, active prospecting was 

soon abandoned at these places and most of the prospect pits arid 

tunnels are now so badly caved that they can not be explored and 

the phosphate beds can not be measured without much additional 

labor. Most of the old prospects were abandoned because the prospectors failed to discover coal of good grade and the real nature of 

the beds apparently remained unknown.

No detailed work has been done in this field on which to base an 

estimate of the quantity of phosphate rock available. It is apparent, 

however, from the reconnaissance examination that in the Snake 

River Range, Bighole Mountains, and Teton Range, particularly 

along the east side of Teton Basin, a large amount of phosphate is
60 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

present. Every acre underlain by a flat bed of phosphate 4 feet thick 

would yield approximately 14,000 tons, and where the phosphate bed 

is steeply tilted the amount beneath an acre is much greater.

The phosphate beds along the southeast side of Teton Basin and 

in the Bighole Mountains are near the tracks of the Victor branch of 

the Oregon Short Line Railroad. In the Snake River Range they lie o o «/

some distance from the Yellowstone branch of the Oregon Short Line, 

but are readily accessible by wagon roads up the Snake River valley 

from Rexburg and Rigby, Idaho. The Rigby route is one that offers 

no unusual difficulties for the construction of a railroad which with a 

short haul would place the phosphate on the main line of the Oregon 

Short Line from Butte, Mont., to Salt Lake City, Utah. The Oregon 

Short Line has made two preliminary surveys from Idaho Falls, 

Idaho, up Snake River to Jackson, Wyo., the first in 1905 and the 

second in 1912. As soon as this road is built it will bring railroad shipping facilities in the Snake River Range within a few miles of the 

phosphate deposits, as the road will extend along the west base of 

the range approximately parallel to the phosphate outcrop. The 

 position of the alinement survey is shown on the map (PI. I) by a 

single black line along Snake River from Jackson, Wyo., to the west 

boundary of the area, west of Prospect, Idaho. The completion of 

this railroad would materially alter the economic conditions of this 

part of Idaho and Wyoming, increase the agricultural population in 

Jackson Hole and Snake River and Salt River valleys, tend 'to make 

the district more popular than ever as the best hunting ground for 

big game in the United States, and greatly stimulate mining activities 

in the phosphate and coal fields.

UTILIZATION OF ROCK PHOSPHATE.

The mining of rock phosphate in eastern Idaho, Utah, and western 

Wyoming is controlled almost entirely by the concerns that manufacture and sell phosphate fertilizer, so that quotations of market 

value of the raw rock at the mines are not readily available and do 

not represent competitive values. All the rock phosphate now shipped 

from eastern Idaho or western Wyoming is sent to the Pacific coast, 

where it is used in the manufacture of fertilizers. In this treatment 

the rock is finely ground and combined with sulphuric acid in nearly 

equal parts by weight, forming acid tricalcium phosphate. This 

material when dried and pulverized constitutes the substance sold 

as superphosphate.

The principal use of the phosphate rock is to fertilize farm lands 

that are deficient in phosphorus, one of the three essential mineral 

plant foods which are not ordinarily present in agricultural soils in 

excess of the needs of growing plants, the other two being potash and 

nitrates. The need for phosphate will undoubtedly become more
PHOSPHATE. 61

apparent with the deterioration of western grain lands. Furthermore, some of the'virgin lands may be deficient in this material and 

would be improved by its application. Although, as principally used 

in fertilizers, phosphate is converted into the more readily soluble 

forms, recent experiments indicate that if the crushed rock is applied 

directly to the soil the phosphorus is gradually made available to the 

plants, and it is likely that in this, form rock phosphate may find one 

of its most important future applications. 

The chief obstacle to the development of the western phosphate 

industry at present is the high cost of transporting the bulky products 

and the lack of markets sufficiently near to warrant the exploitation 

of the deposits. Much of the agricultural land of the Western States 

is relatively new, and as its original phosphates have not been exhausted by past crops it is less in need of fertilizers, except where 

the virgin lands are deficient in phosphorus, than the older farm 

lands in thickly settled communities of the East and South.

The use of fertilizers is said to be fast increasing on the Pacific 

coast, also in other parts of the West where intensive farming is 

practiced. There will henceforth probably be a more rapidly growing 

market for fertilizer products in bo'th the middle West and the far 

West, and it' is to this territory that the western phosphate producer 

must look primarily for markets.

ANALYSES OF PHOSPHATE ROCK.

A number of samples representing phosphate rock in place and phosphate float were collected along the outcrop in the Caribou, Salt River, 

Snake River, Bighole, Wyoming, and Teton mountains, and these 

have been analyzed in the laboratory of the United States Geological 

Survey with the results set forth below. Many of these samples represent small pieces of rock from a part of the phosphate bed that is but 

poorly exposed. Although the material is the best at hand, the 

samples and analyses can hardly be considered truly indicative of the 

character of the material in the undisturbed bed, which may give 

much better results. The localities from which samples of rock 

phosphate or float were obtained are indicated on Plate -I by letters 

A to J, beginning in the southeastern part of the area. Localities A to 

F are in Wyoming, and G to J in Idaho.
Analyses of phosphate rock from eastern Idaho and west

Wyoming.

Letter 

on 

Plate 

I.

A

B

C

D

E

Location.

T.

32 N.

38 N.

39 N.

41 N.

41 N.

41 N.

R.

118 W.

118 W.

116 W.

116 W.

118 W.

118 W.

Sec.

25, NW. £...

3, NW. i....

32, NE. J....

33, NW. i...

15, SE.i..-.

16, NE.J....

Section of phosphate bed 

sampled.

Ft. in.

Black granular rock . . 12 

Soft granular rock .... 12

Analysis of phosphate sample.

A1203 .

5.41

Fe2O3.

0.46

P205.

32.8

Trace.

Equiv

to 

Ca3(P

6

7

2

6

2

6

20-3

2

2

3

6

5

2
F 43 N. 118 W. 29, N. £.....

X

Ft. in.

-,

.......... 78

68

72

7

72

76

Idaho.

G

H

I

J

2N.

2N.

2N.

3N.

1 S.

45 E.

45 E.

45 E.

44 E.

45 E.

25...........

16...........

S............

28...........

-

32...........

Ft. in.

Ft. in.

Ft. in.

4.17

CO

3 91

1 79

1 54

.61

1 11

.71

12. 69

01 no

17.08

16.8

28.93

27

69 

07 

60

3

63
64 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

The analyses show considerable variation but they indicate the 

presence of some high-grade ore that contains approximately the 

equivalent of 70 per cent of tricalcium phosphate. The average of 

ore now being shipped from southeastern Idaho, northeastern Utah, 

and southwestern Wyoming runs about 70 per cent tricalcium or bone 

phosphate. Experience has shown, however, that weathered phosphate rocks are commonly enriched 3 to 5 per cent more, owing to 

the leaching of the more soluble lime carbonate, and that a deposit 

may therefore show a higher value at or near the surface than at 

greater depths. On the other hand, it should be remembered that 

commonly in a region like that examined only the harder and more 

siliceous fragments are found along the outcrop or exposed at the surface, and these may represent a lower value than the richer layers of 

the main phosphate bed.

COAL.

GENERAL OCCURRENCE.

Beds of coal have been found at several localities in this field and 

are at present being mined in a few places. Most of the coal beds 

that have been exploited are of Cretaceous age, belong to the Frontier 

formation, and represent the northward extension of the coal beds 

which are so extensively developed and on which active mines are 

located in southern Lincoln County, Wyo. ; from Cumberland northward to Fontanelle Creek, several miles north of Frontier. Beds of 

coal are also found in rocks stratigraphically below the Frontier 

formation, which probably represent the Bear Kiver coals that have 

been prospected in the vicinity of Sage, Wyo., but on which no active 

mines are located. The coal beds in this, formation consist of coaly 

shale with some impure, irregular lenses of coal, ranging in thickness 

from a few inches to 4 or 5 feet. As a rule the coaly portions of these 

beds are not persistent but wedge in and out. Lumps of usable coal 

may be obtained here and there, but commercial development on a 

large scale is impracticable. The coal beds are widely distributed 

but may readily be separated on structural features into three areas 

the Willow Creek and Grays Lake area, the Pine Creek and Greys 

Kiver area, and the Teton Basin and McDougal area. No special 

effort was made to map the coal beds in any of these areas or to collect sufficient data upon which to base a classification. Wherever 

possible notes on their occurrence were made, and in a general way 

the distribution of the coal-bearing rocks was ascertained while the 

phosphate beds were being examined, although the two for the most 

part do not occur near together. As a result of this preliminary 

reconnaissance examination 979,901 acres, included in an outstanding coal withdrawal in eastern Idaho, was restored to entry on May 

19, 1913.
COAL. 65

WILLOW CREEK AND GRAYS LAKE AREA.

AJ1 the coal beds prospected in the Caribou Range occur along the 

west side of the range from Willow Creek, east of Idaho Falls, southeastward to the headwaters of Blackfoot River, southeast of Grays 

Lake. The beds are believed to be part of the Bear River formation

Approximate boundary of areas Areas included in outstanding Area classified as coal land in'the

within which coal may be found coat withdrawals July I, 191* Horseshoe Creek coal districtenin places by systematic prospect- Areasin Idaho comprising 333.391 amined by E.G.Woodruff in 1912.

ing ordrilli'ng' acres restored March 27.1918 Values range from $20 to $58

Mine X Prospect.

an acre

FIGURE 7. Map showing outstanding coal withdrawals July 1,1914, and the approximate location of the 

coal-bearing formations in the area examined in eastern Idaho and western Wyoming.

but may in places also include a part of the Frontier formation, 

although the writer has little information regarding their age or distribution. So far as known the coal has been opened at only three 

localities, information regarding which is given in the table of sec52756° 18 Bull. 680 5
66 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

tions of coal beds in western Wyoming and eastern Idaho, on pages 

73-75. Development work at one of these localities, the Miller mine, 

was begun in 1900 by the Canyon Coal Mining Development Co., which 

constructed a shaft, tunnel, road, buildings, and machinery at a cost 

reported at $6,000. In 1910 Mr. Miller, one of the members of the 

former company, filed application to purchase and was permitted to 

make payment of $1,600 for 160 acres of coal land at $10 an acre. 

Work was continued, and a shaft 40 feet deep and engine house and 

hoisting machinery were installed at an additional cost of about 

$2,500. The amount of coal that has been mined at this place was 

not determined. The area in which coal beds may be encountered 

by further prospecting is indicated in figure 7. For a further description of the geology of this part of Idaho the reader is referred to the 

paper by Schultz and Richards 1 already cited.

PINE CREEK AND GREYS RIVER AREA.

The coal in the belt extending from Pine Creek to Greys River 

occurs either in the Bear River or the Frontier formation and lies in 

the area between the Absaroka and Darby faults. The structure 

is complex, and the coal-bearing beds may not be present everywhere 

from the north to the south end of the belt. The Frontier formation 

east of the Absaroka fault has been traced from the vicinity of Hilliard, central Uinta County, Wyo., northward to Snake River, a distance of approximately 150 miles, and throughout this area the formation is coal bearing.2

The same belt of Cretaceous rock is believed to extend northward 

to the headwaters of Pine Creek, near the north end of the Snake 

River Range. The Frontier formation is known to be present 

between the Salt River and Wyoming ranges on Greys River and 

Little Greys River, south of Snake River, and may be present between theBighole and Snake River ranges on the divide in Tps. 2 and 

3 N., Rs. 44 and 45 E., where the road crosses from Teton Basin 

to Swan Valley. The coal beds on the divide strike N. 60° W. and 

dip 70° SW. They resemble more nearly the Bear River than the 

Frontier coals. At this locality several prospects have been opened 

and conssderable development work completed. It is reported that 

in T. 3 N., R. 44 E., $4,000 has been expended on improvements, in 

opening drifts and doing assessment work, in an effort to open the 

coal.

In the southern part of Lincoln County, Wyo., the Frontier formation and other Cretaceous rocks lie in a synclinal basin immediately 

east of the Absaroka fault. In places farther north the west limb of 

the syncline has been cut out by the overthrust fault. In the vicin-

» U. S. Geol. Survey Bull. 530, pp. 267-284,1912.

2 U .8. Geol. Survey Buli. 316, pp. 212-241,1907; Bull.543,1914.
COAL. 67

ity of Snake River (see fig. 6, p. 48) the structure of the beds between 

the Darby and Absaroka faults is much more complex, and the 

Frontier formation occurs in a syncline immediately west of the 

Wyoming Range and reappears on the west side of a parallel anticline east of the Absaroka fault. Similar structural conditions may 

be expected between the Absaroka and Darby faults north of Snake 

River. Some of the evidence obtained indicates that the anticline 

and syncline observed on Greys, Little Greys, and Snake rivers 

extends throughout much of the northern area. However, until 

more detailed work has been done and the coal beds have been traced 

along the strike of the formation, it is impossible to state how much 

of the area between the two thrust faults is underlain by coal. The 

beds are in places closely folded and broken by faults. The available 

coal data obtained in this part of the field, although meager, are 

given in the table of coal sections on pages 73-75.

TETON BASIN AND McDOUGAL AREA.

The coal observed in the area extending from Teton Basin, Idaho, 

to McDougal Gap, Wyo., occurs for the most part in the Frontier formation in a narrow belt along the east side of the Bighole Mountains 

and Wyoming Range. The only locality at which coals of Evanston 

age may possibly be found in this area is in the vicinity of Snake 

River south of Cheney, Wyo., but as the structure and age of the beds 

in that locality have not been definitely determined the coal may be 

part of the Frontier or some other coal-bearing formation. Most of 

the coal beds in this area lie immediately east of the Darby fault and 

terminate against it. In places, however, the coal beds lie in a syncline some distance east of the fault, which in these places is in 

contact with pre-Cretaceous sediments. The structure is somewhat 

complex east of the Darby fault, just as it is west of the fault, and the 

coal beds may not be present everywhere along the east side of the 

mountains. The Frontier formation has been traced from the 

north end of Thompson Plateau, in T. 29 N., R. 115 W., northwestward to Snake River in T. 39 N., R. 116 W., a distance of 60 miles. 

Throughout the greater part of this distance the formation dips 

toward the fault, which brings the coal beds into contact with the 

older beds west of it. In the vicinity of Snake River the structure is 

more complex and the coal beds lie some distance east of the fault, as 

explained above. A more complete description of the geology and the 

occurrence of coal in the belt south of Snake River is given in Survey 

Bulletins 316 and 543.

The same belt of Cretaceous rocks occurs northwest of Snake River 

and is believed to be coal bearing where present throughout most of 

the area to the north end of the Bighole Mountains. Near the south 

end of the Teton Mountains the rocks are closely folded, and most if
68 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

not all of the Cretaceous beds have been removed by erosion. In that 

part of the range between station 39 and Trail Creek, or in the west 

flank of the Teton Mountains, the coal-bearing beds are believed to 

be absent, but farther northwest they occur in the same relation to 

the Bighole Mountains and the Darby fault as in the vicinity of 

Snake River and southward in western Wyoming along the east 

side of the Wyoming Range.

On the east bank of Snake River near the center of sec. 34, T. 40 N., 

R. 116 W., coal-bearing beds that are apparently conformable below 

the Almy formation were observed. Whether these coals belong to 

the Evanston, Frontier, or Bear River formation was not determined. 

They were examined hurriedly at only one locality, where they 

afford obscure plant remains that, together with their lithology and 

relation to the overlying conglomerates, afford a basis for their 

tentative correlation with the Evanston formation. If there is an 

unconformity between these beds and the gray calcareous conglomerate of the overlying Almy formation it is not apparent at this 

locality..

At the north end of the Bighole Mountains, along the east side of 

the thrust fault, the Frontier coals occur in at least two areas and 

probably underlie a large part of the valley lands of Teton Basin. 

Coals in this part of the Teton Basin coal field have been found and 

prospected from Mahogany Creek, in T. 4 N., R. 44 E., northward to 

Packsaddle Creek, in T. 5 N., R. 43 E., where the coal-bearing formation passes beneath the Tertiary lavas. The westernmost coal 

area in this part of the field lies immediately east of the Darby fault. 

The coal beds strike N. 40° W. and dip 45°-60° SW. The coalbearing series has been traced for a distance of approximately 4 

miles, and the continuity of the coals throughout this district has 

been demonstrated. Immediately east of this coal area is a prominent ridge of Jurassic beds that separates the coal-bearing rocks on 

the west from those on the east, as shown in figure 8. East 

of the Jurassic ridge only a few exposures of the coal-bearing beds 

were observed, and at only three localities have the beds been prospected. Coal has not been found exposed anywhere in the main part 

of Teton Basin east of the foothills of the Bighole Mountains, as the 

underlying rocks are within a short distance concealed by the Tertiary lava and Quaternary alluvium.

From a general study of the mountains surrounding the basin it is 

apparent that the structure is synclinal and that the basin may consist in part of Cretaceous strata that contain coal, concealed by the 

lava and alluvium. It has been reported that in a well drilled in 1903 

on the old Breckenridge ranch, in the NE. J SE. J sec. 35, T. 6 N., R. 44 

E., west of Haden, a 10-foot bed of coal was penetrated at a depth of 

650 feet. A sample of the coal obtained from the drill cutting yielded
COAL. 69

48.7 per cent fixed carbon.1 The coal, 

if present as reported, probably belongs 

to the Frontier formation and is the 

same as that observed in western 

Wyoming and along the east flank of 

the Bighole Mountains. If the structure in Teton Basin is correctly interpreted and the beds lie in a broad, 

open syncline, coal similar to that observed along the Bighole Mountains 

probably occurs at comparatively shallow depths ranging from a few feet 

along the west margin of the syncline 

to approximately 3,000 feet along the 

lowest part of the syncline. The axis 

of the concealed syncline probably lies 

in the vicinity of Victor, Idaho, and 

extends northward approximately halfway between Canyon Creek and the 

Victor branch of the Oregon Short 

Line Kailroad to the north margin 

of the area mapped in T. 7 N., R. 43 

E. The supposed structure of this 

part of Teton Basin is shown in the 

accompanying section (fig. 8). The 

syncline above referred to lies immediately northeast of the anticline observed 'at the south end of the Teton 

Mountains, in the vicinity of station 

43, and in the Bighole Mountains east 

of the Darby fault, in the vicinity of 

station 41. Whether these two anticlines represent the same anticlinal 

fold was not determined, as the beds 

were not traced from one locality to 

the other. If the Frontier beds were 

eroded along the axis of the syncline 

before the lava was forced over the 

surface no commercial coal will be 

found in the synclinal basin. The 

presence or absence of coal in-this part 

of the field can best be determined 

by means of the drill.

Coal beds of Frontier age occur 

immediately east of the Jurassic ridge

J Bell, R. N., Idaho State Insp. Mines Kept., 1603, p. 65.

-Goal bed

al bed

w ..,-AFrontier formation 

,' ./2 -7 i "-Synclinal axis ?

I l-l 'I '

j \ V^^

tf&\ V* ,'x'-;.|.; F;» '''>: ?.' k

-Phosphate outcrop"'

fill,

> yi IS"
70 PHOSPHATE AND COAL IK IDAHO AND WYOMING.

that crosses .sees. 19, 30, and 32, T. 5.N., R. 44 E., in a southeasterly direction. Very little is known regarding the distribution 

of the coals in this locality, as the sedimentary beds are largely 

covered by Tertiary lavas. On Horseshoe Creek, between lavacovered hills to the north and debris-strewn hills to the south, the 

beds have been opened at three localities in the SW. I sec. 28. One 

of the prospects lies north of the creek and another immediately 

south of it; the third is south of the wagon road that leads from 

Teton Basin to, the Boise and Brown Bear mines. These prospects 

were the first to be opened in this vicinity. The property is locally 

known as the old Flann mine and was first opened in 1882 by Henry 

Flann, a prominent merchant of Rexburg, Idaho, who abandoned 

the enterprise before developing it into a producing mine. Later the 

Idaho Fuel Co. further prospected the coal at this locality and opened 

three drifts. Two beds of coal occur, ranging in thickness from 

20 inches to 4 feet. They strike north and- dip 10° W. The- drift 

on the south side of the creek, according to report, was driven for 

150 feet, and the one on the north for 100 feet. The prospect opening south of the road was driven down the dip. The extent of the 

coal encountered and the length of the slope were not determined, as 

the opening is now caved and the coal in part concealed. A thickness of 2 feet of coal was measured above the caved debris. The 

size of the dumps at these three prospects indicates that considerable 

work has been done and some coal taken out.

Similar coals are reported to occur farther south, on Mahogany 

Creek,, but these were not visited. About half a mile east of the 

prospects on Horseshoe Creek lava caps the hills and forms the 

mountain slopes on both sides of the creek and covers gentle slopes 

out into Teton Basin. The area in which coal-bearing rocks are 

exposed is therefore small and confined chiefly to the valley of Horseshoe Creek and its tributaries, although the same beds may crop out 

on Mahogany Creek and other small streams toward the southeast.

West of the Jurassic ridge coal has been traced from Horseshoe 

Creek north to Packsaddle Creek. This area, examined by the writer 

in a cursory way, was studied in more detail in the fall of 1912 by 

E. G. Woodruff,1 who spent several days in mapping the coal beds in 

this vicinity, collecting data so that the coal lands could be appraised 

and classified. Some of the data on this area here presented were 

obtained from him. Woodruff found that only a small part of the 

area contains coal beds which the miners in the field considered 

thick enough to work in 1912. The coal lands in this part of the field 

range in value from $20 to $58 an acre. The coal beds crop out along 

the slope near the foot of the escarpment and dip toward the over1 Woodruff, E. G., The Horseshoe Creek district of the Teton Basin coal field, Fremont County, Idaho: 

U. S. Geol. Survey Bull. 541, pp. 379-388,1914.
COAL. 71

thrust fault. The beds are cut also by numerous small faults, as is 

well shown in the Brown Bear mine, where seven faults cut the coal 

bed in a distance of approximately 1,200 feet. The rock and coal outcrops are badly caved, so that it is difficult to trace them for any considerable distance without the aid of a drill. The coal prospects that 

have been opened on Horseshoe and Packsaddle creeks, according to 

report, disclose seven separate coal beds that range in thickness from 

2 to 10 feet and are comparatively free from bony coal or waste material. The most extensive development work has been done on the 

Brown Bear, Boise, Horseshoe, and Packsaddle mines, although considerable prospecting has been done at several other places in the 

district. These four properties cover the strike of the coal-bearing 

rocks for a distance of 3 miles, throughout which the continuity of 

. the coals has been fairly well proved. Only the Brown Bear and 

Boise were producing mines at the time of the writer's visit. Mining 

and prospecting had been carried on, however, at other places in the 

field, but the work had apparently been discontinued.

The Brown Bear mine is the chief producer in the field and has 

been operated since 1904. The mine consists of a horizontal rock 

tunnel, 325 feet long from the surface to the coal bed, and two horizontal entries, one to the north 950 feet long and the other to the 

south 250 feet long, both following the strike of the bed, which is 

N. 40° W. The bed ranges in thickness from 4 feet 5 inches at the 

north end to 5 feet 3 niches at the south end and dips 40°-50° SW. 

The mine is worked by the room and pillar method. The rooms are 

turned up the pitch along a drift or entry at 60-foot'intervals, center 

to center. The center of the room is driven ahead, and the coal is 

undermined with a pick along a softer layer, 1 inch to 16 inches 

thick, that lies on the floor of the mine, and blasted down with a 

back hole and a small charge of black powder. The broken coal 

slides down a chute at the narrow outlet of the room and is hauled 

to the entry. The mine is well ventilated by raises to the surface 

and cross courses through the pillars. A good deal of the coal produced in 1912 was sold at the mine as mine run for $2.50 a ton. 

Some of it was screened and sold for $3.50, and the slack was sold 

for 50 cents a ton;

The Boise mine was not selling coal at the time of the writer's 

examination, but arrangements had been made to mine a few tons 

daily for use in Teton Basin. The coal bed here is 38 inches thick, 

is entirely free from bone and waste of any kind, and lies between 

beds of shale. The mine consists of a rock tunnel 150 feet long, that 

crosscuts the strata, and an entry 200 feet along the bed from the 

point where the tunnel enters the coal. The mine was opened in 

1904 and has been supplying some excellent coal at irregular intervals since that time.
72 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

The Horseshoe mine is near the southeast corner of the NW. J 

NW. J sec. 6, T. 4 N., R. 44 E., and was opened by the Horseshoe 

Coal Co. prior to 1902. The bed is approximately 10 feet thick and 

dips 66° SW. The small dump at the mouth of the mine indicates 

the extent of the workings and represents the waste taken out in 

mining. The development work consists of a single entry, 500 feet 

long, extending north into the side of a steep hill where the bed was 

exposed. Although badly caved the mine can be entered for a distance of 200 feet or more, and good sections of the bed measured. 

Several thousand tons of coal was extracted and sold at the mine for 

$2 a ton. The mine was poorly developed, and this in part furnishes 

an explanation why the work at this locality soon became dangerous 

and the prospect was abandoned.

The Packsaddle mine lies in the NE. £ sec. 26 and the NW. $ sec25, T. 5 N., R. 43 E. There are two openings at this place, both of 

which are badly caved, so that it was impossible to determine the 

relations of the workings in the lower one to those in the upper one. 

The dump at the mouth of the mine contains some good coal, and 

the general improvements, including a Victor standard scale, mine 

buildings, miners' cabin, and coal road, indicate that considerable 

work was done here and some coal mined. No coal is exposed in 

the mouth of the lower entry, the small sticks or poles used in timbering are broken, and the entrance to the coal bed is cut off by 

caved ground, so that no data as to the character or thickness of the 

coal were obtained. Some coal has also been taken from the upper 

drift. This entry likewise was badly caved, but coal exposed at its 

mouth indicates that the bed is more than 2 feet 30 inches thick 

no doubt much more, as the caved material conceals the lower part 

of the bed. The entire bed is reported to be 9 feet thick and to 

terminate against a fault. The mine was opened in 1906, and work 

was continued for a year or more before the property was abandoned. 

On the ridge just south of the abandoned mine the gray sandstone 

strikes N. 20° W. and dips 50° SW.

SECTIONS OF THE COAL BEDS.

The location of the prospect pits which were examined during 

this survey or from which reports have been obtained and the 

sections of coal beds exposed in them are given in the following 

table. The mines, prospect pits, surface diggings, and coal exposures are numbered consecutively from 1 to 37, beginning at the 

southeast corner of the field, and the numbers agree with those used 

on Plate I. Nos. 1 to 10 are in Wyoming and Nos. 11 to 37 in Idaho.
Sections of coal beds 'in eastern Idaho and western W

Wyoming.

No. 

on

Plate 

I.

1

2

3

4

5

7

8

9

10

T.

36 N.

37 N.

37 N.

37 N.

37 N.

37 N.

37 N.

38 N.

39 N.

40 N.

I

R.

117 W. 

116 W.

116 W.

116 W.

116 \V.

116 W.

116 W.

116 "W.

116 W.

116 W.

.location.

Sec. '

18, SW.J.. ................ 

1, SW. iSE.J... .........

l.SW.JSE.i. ...........

1, NW.JSE.J..... .......

1,NW.JSE. }..... .....

1, W. JSE.l..............

1, SW: JSE. }............

11, NW.JSW.}. .........

27, SW.JSW. i...........

34, SW.iNE.J... ........

Frontier. ..........

Frontier (?).......

(?)

Ft. in. 

Coal.................. 3

Coal.................. 3 6

Coal.................. 4 6

Coal.................. 7 6

Clay................. 1

Coal. 

Coal.................. 2 3

Coal (?).

Shale.

Coal.................. 1 5

Clay.

Anal

No

4

4

4

4

4

a Bed sampled.
Sections of coal beds in eastern Idaho and western Wyom

Idaho.

No. 

on

Plate 

I.

11

12

13

14

15

16

17

18

19

20

21

22

23

T.

IS.

IN.

2N.

3N.

3N.

4N.

4N.

4N.

4N.

5N.

.5N.

5N.

5N.

I

R.

40 E.

42 E.

40 E.

44 E.

45 E.

44 E.

44 E.

43 E.

43 E.

44 E.

44 E.

44 E.

vocation.

Sec.

24, SE.iSE.i.. ..........

OQ

34, SE. } NE. }; NE. }

SE. }; 35, SW. } NW. }; 

NW. }SW.}.

24.........................

1Q

35, SE.}SW.}. ..........

19, SW. }SW. }...........

19, SW. }..................

2, SE.}SW.}. ...........

28, SW.} .................

28, SW.}. ................

28, SW.}. ................

32. NW. i.................

Frontier (?).

Frontier (?).

Frontier (?).

Frontier.

Frontier.

m. ...............

Coal (?).

Coal.................. 4?

Coal.................. 3 6?

CoaL... .............. 2 4

Coal.................. 4

Coal (?).

Coal (?).

Coal (?).

Coal (?).

\to 4 8 

Reported coal blossom 4

An

N

1

!
24

25

Oft

27

OQ

29 

30

<*1

<v>

OQ

^4

3S

V7

4N.

4N.

4N.

4N.

5N.

5N.

1 TJ

=; TJ

5N.

e "NT

5N.

5 TJ

5N.

5N.

44 E*

44 "P

40 T?

xq TTI

43 E. 

43 E.

43 E.

40 "R

43 E.

43 E.

4O -p

40 17

4O T^

6, NW.}........... .......

6, NW.iNW.J.. .........

1,SE. JNE.J.. ...........

1,SE.JNW.J.. ..........

71 QTUT 1 QW 1

25,SE. JSE.i............ 

25, SE.JSW.J..... ......

25, NW.JNW. }..........

26, NE.iNE. }...........

24, SE.JSE. }............

24, SE.iSE. }............

Frontier ..........

Coalo.. .............. Ill

Coalo................ 3 4

Coal, bony........... 1 9

Coal.................. 2 2

Coal.................. 3

Shale................ 2

Coal.................. 3 8

Shale................ 1 10

Coal.................. 4 3

Shale................ 4

Coal.................. 5± 

Coal.................. 3 2

seen. 

Shale................ ?

Coal.................. 2 3

Coal.................. 3 4

Coal.................. 1 1

Coal.................. 3 4

Coal.................. 1 7

Shale................. 10

Coal.................. 1 1

15

1

Bed sampled.
76 PHOSPHATE AND COAL IN" IDAHO AND WYOMING. 

CHARACTER OF THE COAL.

The coal is bituminous and rather free from impurities. According to report some of it has been coked with fair success. However, 

the tests made in an agate mortar gave noncoking results. Most 

Of the coal is badly shattered, as would be expected in a region 

where so much faulting has taken place. As a result of this shattered condition a large percentage of the coal in mining comes out 

fine. Even the larger pieces are so broken that they do not readily 

stand handling, and much of it is necessarily marketed as slack. 

The present market for the coal produced in this field is largely confined to the settlers who live within hauling distance of the mine. 

The coal is extensively used by the farmers to run then* steam engines 

during the plowing, seeding, and harvesting seasons, and by the 

thrasher and header crews. In 1912 it sold at the mine for $3.50 a 

ton for lump coal, $2.50 for run-of-mine, $2 for the small sizes, and 

50 cents for slack. A good deal of the lump coal is hauled to St. 

Anthony and other railroad settlements, where it generally commands 

$1 a ton more than the coal that is shipped in from the Mississippi 

Valley region, as it is apparently much better, has a higher heating 

value, and contains less ash.

Samples of coal from the Frontier formation have been collected 

for analysis from several localities in this region and the results are 

given in the following table. The sampling was done.according to 

the regulations of the United States Geological Survey, which require that the sampled face must be cleared of weathered coal, 

powder stains, and surface impurities. A channel is then cut across 

the bed to obtain the sample, and at the same time large partings or 

lumps of impurities are rejected. The sample is collected on a 

sampling cloth, then broken up to pass through a £-inch mesh sieve, 

mixed thoroughly, quartered, and mixed again, and finally the sample 

is placed in a sealed can to be forwarded to the chemical laboratory.
Analyses of coal samples from Frontier formation of eastern Idaho a

[First five analyses made at United States Geological Survey fuel-testing laboratory; F. M. Stanton, chemist in ch

the Bureau of Mines; A. C. Fieldner, chemist in charge

No. 

on 

Plate 

I.

1 

2 

3

7

10 

29 

24

Location.

Greys River, SW. J sec. 18, T. 36 N., R. 117 W.. 

Wyoming Range, SE. J sec. 1, T. 37 N., R. 116 W. 

Wyoming Range, SE. J sec. 1, T, 37 N., R. 116 W. 

Wyoming Range, SE. i sec. 1, T. 37 N., R. 116 W.

Snake River, NE. } sec. 34, T. 40 N., R. 116 W. . 

Brown Bear mine, SE.isec.25,T. 5N., R. 43 E. 

Horseshoe mine, NW. i sec. 6, T. 4 N., R. 44 E . .

Laboratory 

No.

. 4323 

4302 

4301 

4003

4002 

15115 

15116

Airdrying 

loss.

3.6 

2.3 

6.0 

4.6

7.9 

. 8.3 

4.3

Form 

of 

analysis.0

A 

B 

C 

D

A 

B 

C 

D

. A 

Bc 

D

. A 

B 

C 

D

A 

B 

C 

D

A 

B 

C 

D

A 

B 

C 

D

Ch

Proximate.

Moisture.

7.8 

4.4

6.8 

4.6

10.7 

5.0

10.1 

5.7

18.3 

11.2

11.5 

3.4

7.7 

3.6

Volatile 

matter.

36.3 

37.6 

39.3 

40.0

33.4 

34.2 

35.9 

38.4

30.7 

32.6 

34.3 

36.1

32.9 

34.5 

36.6 

38.2

23.2 

25.2 

28.3 

40.2

37.2 

40.6 

42.0 

44.2

39.7 

41.5 

43.0

44.1

Fixed 

carbon.

54.3 

56.3 

58.9 

60.0

53.6 

54.9 

57.5 

.61.6

54.3 

57.8 

60.9 

63.9

53.3 

55.9 

59.3 

61.8

34.4 

37.4 

42.2 

59.8

47.0 

51.3 

53.1 

55.8

50.4 

52.6 

54.6 

55.9

Ash.

1.62 

1.68 

1.76

6.1

6.33 

6.63

4.2

4.55 

4.79

3.70 

3.8

4.1

24.0

26.1

29.4

4.39 

4.69 

4.86

2.2 

2.3 

2.4

0 A, Coal as obtained in the mine; B; coal dried at a temperature of 30° to 35° C.; C, moisture-fr
78 PHOSPHATE AND COAL IN IDAHO AND WYOMING.

Sample 4323 was collected from a shallow prospect on the west 

side of Greys River a few miles south of the mouth of Little Greys 

River, in what is known as the Greys River coal field. The sample 

was taken a few feet below the surface and represents a coal of good 

quality, which nevertheless may have been partly altered by 

weathering.

Sample 4302 was collected from a prospect pit in the Wyoming 

Range that had been exposed to the atmosphere for more than a 

year, and as a result the coal had no doubt been considerably altered. 

The lower part of the 3 feet 6 inch coal bed is composed largely of 

bone, but the upper 2 feet, which was sampled, is a good clean coal. 

The sample was taken 40 feet stratigraphically below sample 4301.

Sample 4301, from a shallow prospect in the Wyoming Range, 

represents a coal bed 3 feet 9 inches thick which was moderately 

weathered. The sample as collected does not include a 7-inch 

parting that is present in the bed at this point. The coal bed lies 

approximately 40 feet stratigraphically above sample 4302, and the 

coal is of the same quality.

Sample 4003 was collected from a. surface prospect in the Wyoming 

Range, in which the coal bed clearly shows the effects of weathering. 

The 3-foot bench of coal that lies near the middle of the measured 

section (see table, p. 77) is the only part of the bed included in the 

sample.

Sample 4002 was taken from a cut in a coal bank on Snake River, 

where 1 foot 5 inches of coal was exposed. It represents a surface 

outcrop in which the coal was so greatly altered by weathering that 

the sample does not fairly represent the quality of the coal.

Sample 15115, collected by E. G. Woodruff in 1912 from the Brown 

Bear mine, in the Bighole Mountains, was taken from the end of the 

north entry, 950 feet from the portal, where mining had been done 

recently and where the coal was unweathered. This sample is 

believed to represent the coal in its normal condition as taken from 

the mine.

Sample 15116, collected by E. G. Woodruff in October, 1912, from 

the abandoned Horseshoe mine in the Biighole Mountains, was moderately weathered. It was taken at a point 200 feet from the portal 

from a face that had been exposed for more than a year. The surface 

of the bed was cleaned until apparently fresh coal was obtained, but 

it seemed probable that some change which had not altered the 

physical appearance of the coal may have taken place, because the 

mine is in a fairly dry climate and had remained open to the unrestricted circulation of the air for a long time. Nevertheless, the 

sample gave a higher calorific value than the unweathered coal from 

the Brown Bear mine. This result is probably to be explained in
tT. S. GEOLOGICAL SURVEY BULLETIN 680 PLATE II

BURLAP TABLES ARRANGED FOR SAVING FINE GOLD NEAR THE 

MOUTH OF McCOY CREEK ON SNAKE RIVER, IDAHO.

S. PUBLIC SCHOOL BUILDING AT IRWIN, IDAHO, CONSTRUCTED OF

RHYOLITE BLOCKS QUARRIED IN THE VICINITY. 

Baldy Mountain, a part of the Snake River Range, in the background.

C. AURIFEROUS GRAVELS AND ALLUVIUM CARRYING FINE FLAKES OF

GOLD. 

Note large pebbles along sluicing ditch from which finer material has been washed.
GOLD AND OTHER MINERALS. 79

part by the smaller amount of ash in the Horseshoe sample and the 

fact that very little alteration had taken place in the coal bed during, 

its exposure to the circulation of the air.

GOLD AND OTHER MINERALS.

Placer mining has been done along Snake River and its tributaries since 1860. The gold on these streams occurs in the gravels 

that form terraces along the streams and in the deposits of boulders, 

gravel, and sand that fill the channels or form the beds of the streams. 

A small placer working was observed on Snake River just below the 

mouth of Wolf Creek. At the time of visit the work had been discontinued for the winter, and no details regarding the gravels were 

obtained. The deposits along Snake River are more fully described 

in Survey Bulletins 315, 530, and 543. There,are no metalliferous 

mines in this region, and only a little desultory prospecting is carried 

on. Most of it has been done in pre-Cambrian rocks in the Teton 

Mountains, where a little lead, silver, and copper have been reported. 

Structural material, lime, cement, clay, and road dressing may be 

obtained in many localities. Excellent building stone is obtained 

from the Tertiary rhyolite, which has been extensively used for public 

buildings and private dwellings in certain parts of the area. The rock 

is soft enough to be easily quarried and firm enough to be dressed to 

any desired shape. (See PL II.)

Reports of occurrences of oil in eastern Idaho have been received 

from time to time. If the anticline along the west side of Teton 

Basin has a closed structure, there may be oil in this part of the 

field. An oil well was drilled in 1903 some distance east of the 

synclinal axis that passes through the basin. The following statement regarding this well was furnished in the fall of 1906 by Mr. 

Spencer Clawson, 131 South Main Street, Salt Lake City, Utah:

The president of the Fremont County Oil, Gas & Coal Co., W. E. McDonald, a native 

of the oil section of eastern Indiana and later of Florence, Colo., visited the Teton 

Valley in 1900 with a view, it is said, of purchasing a ranch; he negotiated with me 

for 800 acres of land at the crossing of Teton River near Hayden and made a payment 

upon it; later he called and stated that there were very strong surface indications of 

the presence of oil on the land, his long residence in the Indiana and Colorado oil 

fields qualifying him to judge.

I paid but little attention to the man or his enterprises, and he returned to his 

former home in Colorado, organized the Fremont County Oil, Gas & Coal Co., and 

vigorously prosecuted the work of boring for oil on the ranch of David Breckenridge, 

which joined the lands Mr. McDonald had purchased from me on either side; his 

difficulties were great, as it was about 30 miles to Rexburg or St. Anthony, the nearest 

railroad point, and transportation of engine, boiler, pipe, etc., was both difficult and 

expensive; but he was a man of perseverance, though of moderate resources, and 

he expended the capital of the company, some $6,000, before he found anything that 

indicated values. His enthusiasm was unbounded, and through great effort he 

procured more money and continued his work.
80 PHOSPHATE AND COAL 1ST IDAHO AND WYOMING.

In the fall of 1903 his 8-inch drill struck a seam of coal at a depth of about 650 feet, 

and he told me that he had driven 10 feet into the seam without reaching the footwall; he then withdrew his drills in order to sink the 10-inch pipe casing.

The supply of pipe being exhausted, he suspended operations and returned to 

Colorado for more material and money. On his way east he stopped at Salt Lake 

City and urged me to join him in his efforts to develop the coal and oil, which he 

asserted would be struck at greater depth.

As he failed to make the second payment on the purchase price of the land, I was 

unable to render him the financial aid he desired. I never saw Mr. McDonald again, 

but subsequently learned that he was taken ill in Florence, Colo., and after a brief 

illness died in a hospital there.

The enterprise was abandoned by his administrators; his creditors removed the 

engine, boiler, drills, etc., leaving only the derrick and the 10-inch pipe casing in the 

well. The land was sold by the sheriff and was purchased by me for the interests 

that formerly owned it.

Another source of oil that promises to be of some value occurs at 

the same horizon as the phosphate deposits in Montana, Idaho, and 

Wyoming that is, in the Phosphoria formation. The phosphate on 

applying heat to the rock is not driven off by distillation but remains 

in the ash. Evidence of petroleum or bituminous compounds in 

rocks of this age has been observed over wide areas by the writer, 

who has worked on the phosphate deposits, but few, if any, tests 

have heretofore been made to ascertain the quantity of oil. Small 

remnants of samples of phosphate rock, E, G, H, I, and X, collected 

in Idaho and western Wyoming for phosphate determinations, were 

also tested for oil.

Tests of phosphate rock containing oil in eastern Idaho and western Wyoming.

[Chase Palmer, U. S. Geological Survey, and C. S. Reeve. Office of Public Roads and Rural Engineering,

analysts.)

No.

E....

G....

H....

I.....

X....

Location.

^Frail Lickil ProMr ^xcoiVj "Wvn vv yvt f

NE.isec.16, T. 

41 N., R. 118 W.

Palisade Creek,

Idaho, sec. 25,

T.2N.,R.45E.

South Fork of Raney Creek, Idaho, sec. 16. T. 2 

N..R.45E.

North Fork of Raney Creek, Idaho, sec. 8, T. 2

N., R. 45 E.

Young's ranch,

southwest of

Lander, Wyo., 

sec. 8, T. 31 N.,

R. 99 W.

Laboratory

No. 

(Office of 

Public 

Roads 

and 

Rural

Engineering.)

19781 l^/ol

12782

12783

12784

12785

Phosphorus 

pentoxide 

(Pi04 ).

Trace

12.69

31.69

17.08

24.3

Tricalcium 

phosphate 

(CarfPOM.

TVnpf* J-ld.Lt>.

27.8

69.4

37.4

53.16

Specific 

gravity.

1.93

2.33

2.24

2.64

2.31

Petroleum.

Dry 

distillation 

(gallons per

ton).

A little oil o.

Little oil distillate.a

A little oil o.

.....doo.....

3.17.........

Carbon 

tetrachloride 

extraction.

Little:......

Very little.. .

.....do......

.....do......

Some........

Carbon disulphide 

extraction

(per

cent).

0.34

.79

.98

1.19

4.89

a Mr. Reeve omitted the dry distillation of these samples because so little material was submitted as to 

make it practically impossible to obtain results of any value.
WATER POWER. 81

The rocks in the region where the samples were obtained have 

been subjected to extreme pressure and affected by metamorphism, 

as shown by the faulting and squeezing manifested at many places 

and by the crystallization of the limestone. A considerable part of 

the organic matter that was originally in the rock may therefore 

have undergone partial distillation, a supposition that in turn may 

account for the relatively small quantity of oil obtained from these 

rocks. If the rocks in which the small quantities of oil are found 

have already undergone partial distillation, the question arises, 

What has become of the distillate? Where the rocks are exposed 

the oil has undoubtedly escaped, and this may account for the slight 

yield on extraction from rocks that give off a strong odor of petroleum. 

Where the rocks are not exposed they may have been a source of supply of petroleum in areas where the structural conditions are favorable 

to its accumulation. It may therefore be possible that commercial 

accumulations of oil have been formed in these older Paleozoic rocks. 

If this should be true, it would open up a new field for exploration 

in this part of the Rocky Mountain region. Thus far. the Lander 

oil field in Wyoming seems to be the only place where oil has been 

obtained in commercial quantities from rocks of the same age, though 

indications of oil at this horizon have been noted at several other 

places in Wyoming and Utah.

WATER POWER.

This area affords one conspicuously good opportunity for developing large quantities of water power, near the mouth of the Snake 

River canyon. Throughout the remainder of the area there are 

numerous localities where small plants can be installed whenever 

suitable markets are developed. The creeks that flow from the 

Caribou, Snake River, Salt River, Bighole, Wyoming, and Teton 

mountains are all permanent, and in their canyons there are many 

places where dams can be built to advantage and small power of low 

head developed. There are, however, very few falls of any consequence and only a few localities, as in the canyon of Snake River and 

in the canyon of North Fork of Teton River, where considerable 

head may be obtained. Snake River is the only stream in which a 

large, body of water is available. 

52756° 18 Bull. 680 6

INDEX.

Page. 

Absaroka fault, coal beds near............... 66-67

northwesterly extension of............... 41

results of................................ 36

Adaville formation) possible occurrence of.... 29-30

Afton Creek, phosphate rock on.............. 40

Alluvium, distribution of.................... 33

gold-bearing, plate showing.............. 78

Almy formation, occurrences of............ 30

Ankaroh shale, nature and occurrence of..... 25

Aspen formation, nature and occurrence of... 28

Bailey Creek, phosphate near................ 50

Bear Creek, Idaho, phosphate rock on....... 39-40

Bear River formation, nature and occurrence

of................................ 27-28

Bcckwith formation, nature and occurrence of 26 

Bighole Mountains, coal in................... 67-72

phosphate rock in..................... 50,52-56

structure of.............................. 36-37

Bighorn dolomite, nature and occurrence of... 19 

Blackwelder, Eliot, cited........... 42,51-52,57-58

reconnaissance by....................... 9-10

Boise mine, description of................... 71

Bradley, Frank H., cited................. 31,32,33

report by............................... 9

Brazcr limestone, nature and occurrence of.... 21

Brcckcnridge well, coal reported in........... 68-69

Brown Bear mine, description of............. 71

analysis of coal from..................... 77,78

Building materials, occurrence of............ 79

Burlap tables arranged for saving fine gold,

plate showing.................... 78

Cambrian system, formations of.............. 17-19

Canyon Coal Mining Development Co., operations of.......................... 66

Carboniferous system, formations of.'......... 21-24

Caribou Range, coal beds in................. 65-66

phosphate rock in....................... 39-40

structure of.............................. 33

Clawson, Spencer, cited...................... 79,80

Coal, analyses of............................. 77-79

mining of.......................... 66,70,71-72

nature of................................ 76

occurrence of.......... 27,28,48-49,53,55,64-72

sampling of.............................. 76

Coal beds, sections of........................ 72-75

Coal lands, restoral of, to entry.............. 64

Copper, occurrence of........................ 79

Counts's ranch, phosphate rock near......... 51-52

Cretaceous system, formations of............. 27-30

Darby fault, coal beds near.................. 66,67

northwestward extension of.............. 55

Devonian system, formations of.............. 20-21

Dolomite, Silurian, nature and occurrence of.. 20 

Drainage of the region....................... 11

Page. 

Elk, hunting ground for..................... 11,60

Elk Creek, Wyo.-Idaho, phosphate rock on... 45-46 

Eocene series, formations of.................. 30

Evanston formation, coal in................. 67

possible occurrence of.................... 30

Fall Creek, hot springs on................... 32

phosphate rock on....................... 39-40

Faults, positions and results cf.............. 35-37

41,43,44,45,40,52,55 

Fertilizer, phosphate, manufacture of........ 60-61

Flann mine, operation of.................... 70

Flathead quartzite, nature of................ 18

Fossils, occurrence of. 20,21,22,24,26,27,29,41,55,68 

Frontier formation, nature and occurrence

of............................... 28-29

Gallatinlimestone, nature and correlation of. 19 

Game, habitat of............................ 11,60

Garden Creek, phosphate rock on............ 39-40

Geography of the region..................... 10-12

Geology of the region........................ 12-37

Georgetown Canyon, phosphate rock in...... 38-39

Glacial deposits, nature and occurrence of... 31 

Gold, gravels and alluvium bearing, plate

showing......................... 78

occurrence of............................ 79

Grand Teton, altitude of.................... 37

Gravels, gold-bearing, plate showing......... 78°

terrace, distribution of................... 33

Grays Lake area, coal beds in............... 65-66

Greys River area, coal in.................... 66-67

Gros Ventre formation, nature and correlation of........................... 18-19

Gros Ventre Mountains, phosphate rock in.. 58

Haden, Idaho, coal bed west of.............. 68-69

Hay den Survey, exploration by ............. 9

Heise, Idaho, hot spring at.................. 32

Hilliard formation, possible occurrence of.... 29-30

Hoback Range, phosphate rock in........... 58

Horseshoe Creek, coal beds on............... 70-71

Horseshoe mine, analysis of coal from..... 77,78-79

. description of........................... 72

Idaho Fuel Co., coal mining by.............. 70

Igneous rocks, nature and distribution of.... 34-35

Indian Creek, Caribou Range, phosphate

rock on......................... 39-40

Indian Creek, Snake River Range, phosphate

rock on......................... 46-47

Irwin, Idaho, school building constructed o f

rhyolite, plate showing.......... 78

Itinerary of the reconnaissance.............. 10-11

Jackson Hole, phosphate rock near.......... 58

Jefferson limestone, nature and occurrence of. 20-21 

Jurassic system, formations of............... 25-26

83
84 INDEX.

Page. 

Kindle, E.'M., cited......................... 21

Knight formation, nature and occurrence of.. 30

Lavas, nature and distribution of........... 34-35

Lead, occurrence of......................... 79

McDougal Gap area, coal in................. 67-72

Madison limestone, nature of................ 21

Mahogany Creek, coal beds on............... 68,70

Mansfield, G. R., reconnaissance by......... 49

Map of the region, showing the distribution

of phosphate and coal deposits... 12 

Miller mine, development of................. 66

Mineral deposits, nature and distribution of. 37-81 

Mississippian series, formations of.. 1........ 21

Moraine, recent, formation of................ 31

Mountains of theregion..................... 11

Nugget sandstone, nature and occurrence of. 25

Oil, indications of........................... 79-81

Ordovician system, formation of............. 19

Packsaddle Creek, coal beds on........... 68,70-71

Packsaddle mine, description of............. 72

Palisade Creek, phosphate rock on........... 44

Palmer, Chase, analyses by.................. 80

Pennsylvanian series, rocks of.............. 22

Permian series, rocks of..................... 23-24

Phosphate rock, analyses of................. 61-64

discovery of............................. 37-38

distribution of........................... 37-58

formations containing ................... 16-17

mining of................'............;... 59-60

nature of................................ 38

utilization of............................. 60-61

Phosphoria formation, nature and occurrence

of................................ 23-24

° oilin...................................... 80-81

Pine Creek, phosphate rock on............... 41-42

Pine Creek area, coal in...................... 66-67

Pliocene series, possible occurrences of....... 31

Pre-Cambrian rocks, nature and distribution of 17 

Pritchard Creek, phosphate rock on......... 39-40

Purpose of the investigation................. 7-9

Quaternary system, deposits of.............. 31-33

Railroads in the region.................... 11-12,60

Rainy Creek, phosphate reck on............. 42-44

Reeve, C. S., analyses by.................... SO

Rex chert member, nature and occurrence of. 23-24 

Rhyolite, school building at Invin, Idaho,

constructed of, plate showing.... 78

St. John, Orestes, reconnaissance by. 9,54-55,55-56 

Salt River Range, phosphate rock in......... 40-49

structure of.............................. 35-36

Section, generalized, of the region............ 12-15

Silurian system, rocks of..................... 20

Silver, occurrence of......................... 79

Snake River, analysis of coal from........... 77,78

gold on.................................. 79

hot springs on........................... 31-33

phosphate rock on....................... '47-49

Snake River basalt, nature and distribution

of................................ 34-35

Snake River Range, phosphate rock in...... 40-49

structure of.......................'....... 35-36

Springs, hot, occurrence of...................' 31-33

Stanton, T. W., fossils determined by.... 27,28,29

Stone, building, occurrence of................ 79

Stratigraphy of the region................... 12-35

Structure of the region....................... 35-37

Superphosphate, manufacture of............. 60,61

Surveys, earlier.............................. 9-10

Tertiary system, formations of............... 30-31

Teton Basin, structure of.................... 69

Teton Basin area, coal in.................... 67,72

Teton Mountains, phosphate rock in......... 56-58

structure of.............................. 37

Thaynes limestone, nature and occurrence of. 24 

Threeforks formation, nature and occurrence

of................................ 20-21

Topography of the region.................... 11-12

Travertine, deposits of....................... 31-33

Triassic system, formations of............... 24-25

Tufa, deposits of............................. 31-33

Twin Creek limestone, nature and occurrence

of................................ 25-26

Water power, streams available for.......... 81

Wells formation, nature and occurrence of... 22 

Willow Creek area, coal beds in............. 65-66

Woodruff, E. G., reconnaissance by......... 10

Woodside formation, nature of............... 24

Wyoming Range, coal in................. 67-72,78

phosphate rock in....................... 50-52

structure of.............................. 36-37

o