DEPARTMENT OF THE INTERIOR

HUBERT WORK, Secretary

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Director

Bulletin 756

OIL AND GAS FIELDS OF THE

LOST SOLDIER-FERRIS DISTRICT

WYOMING

BY

A. E. FATH

AND

G. F. MOULTON

WASHINGTON

GOVERNMENT PRINTING OFFICE

1924
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CONTENTS.

	PageIntroduction _____-________-___-____-_-_-_-_------------------_--_ 1

Summary of geologic results________________-___-_--_-__---__-____ a l

Field work..__...__.__._________-_--.-_____-___-._.--.--._-_. 3

Previous geologic investigations....-..-.-...____-__._--_____-.__._-. 4

Acknowledgments _______-__-_-___---_-----__-----.-----------_.-_ 5

Geography._________-_________________--_-__---___----_-----_---_ 5

Location and accessibility._____________________________________ 5

Topography._____________________-___--___-__-_---_--__--____ 6

Water supply.__________--__-_-_______-_-_----_------_---_-_-_ 7

Vegetation _______-___-_______________-_-__--__----------__-__ 7

Culture._____.___________....... ---...-____... 8

Markets for oil and gas________-_-________--_-___-_---__--_____ 8

Stratigraphy. .________-_____L______________-_____-_--_-___-__-___ 9

Generalized section__________________________________________ 9

Pre-Cambrian crystalline rocks____-______-----_-----_-_-----__- 12

Cambrian quartzite -______--________---_-----__------_---- r --- 12

Mississippian rocks._--___-____-_-.__-_-__________-__-_--__---- 12

Madison limestone._____-__-__-_-_____-__---_____-__--_--- 12

Pennsylvanian rocks.._______-___-____________-__-___-___.-._-. 13

Amsden formation.____________-__-___-_____-_-_--__-_--__ 13

Tensleep sandstone______-_-_-___-___-___-------_-_-__-__ 13

Permian and Triassic red beds._-__--_-__-____--_----__-___----- 14

Jurassic and Cretaceous (?) rocks____----------_------__---___-- 16

Sundance and Morrison formations.. __-_-_--__---_____-__-_, 16

Cretaceous rocks______________________________________________ 17

Cleverly formation._____-_-_---___--__-__--______-__-_-_-- 17

Thermopolis shale__-_---_--___-------------_-----___-_--_- 19

Mowry shale.___-________-__-_-_--__-______--______--_--_ 20

Frontier formation.____________________^____--____________ 21

Carlile and Niobrara shales-_-__---_---------__.--______--__ 23

Steele shale.-.____________-_------ -________------- 24

Mesaverde formation._____________________________________ 26

Lewis shale_____________________________________________ 28

Distribution of oil and gas.____________________________________ 28

Structure._--_-__-_________---_-_____----_____-_----------_-___-_ 30

Regional features._.___.-.--__---_-_-----_----__--^----_--__-. 30

Method used in representing structure.__________________________ 31

Effects of steep dips.___--___-__-_-_____-__-____-__--_____-_.__ 32

Oil and gas fields..._-._.-___-_-__-_-___-----_--_--___-__-___^___- 33

Lost Soldier dome__-__-__-_---__---_-----_____-_-__-_____-__ 33

Surface geology and structure_-___-_-__-__-_-_---__--___--__ 33

Drilling operations.___________- i ___.______________________ 34

Untested deep sands_---__---__------_-___-___--____-_-_-_ 35

Character of oil.___________________________________________ 35

Production. ______ ________________________________________ 36

Wertz "dome"..._______________...____.____ 36

Surface geology and structure___-____--_----_-_.________-_ 36

Drilling operations._-_-----__-_-__-_-_--_-_---_-_---____._ 37

Eastward extension of Wertz "dome"____..-_________________ 39
IV CONTENTS.

Oil and gas fields Continued. Page

Bunker Hill dome----___-------___-_-----_---__--_--_------___ 39

Mahoney domes___----_-____-_____---_--___________-__._..___ 40

Surface geology and structure...........____________________ 40

Drilling operations._______________________________________ 41

Ferris dome._________________________________________________ 43

Surface geology and structure._____--____-_---__-_-_--_-_._ 43

Drilling operations.___-______________.____-_______---___-. 45

Productivity of wells and quality of the oil and gas____________ 45

G. P. "dome" _______________________________________________ 46

Surface geology.__________________________________________ 46

Stratigraphic position of G. P. pay sand.____________________ 46

Possible forms of structure.________________________________ 47

Production.______________________________________________ 49

O'Brien Springs anticline-------------------------------------.- 50

Sherrard dome._-___---______---____----___.____--______------ 51

Separation Flats anticline.___-____-----_-____--_------_-_--_--_ 52

Petroleum analyses._._____-____-_________--_-__________-_-_..__-__ 54

Determinations of porosity.-__--_-_--_-------________-___-___--._-_ 55

Index._________-_______-________-___-_---______--_-_-___-_---.-_ 57

ILLUSTRATIONS. f

Page. I

PLATE I. Map of the Lost Soldier-Ferris district, showing areal geology ,( 

and structure of the Wall Creek sand.-.----------------.- 4

II. A, Sand dunes in sec. 36, T. 26 N., R. 87 W.; B, Large exposure i 

of bedrock shale in the sand-covered region; C, Whisky Gap, f 

cut through Tensleep sandstone.______-__-_______-_-_-_ 8 V

III. A, Ferris Mountains; B, Walls of steeply dipping Frontier sand- * 

stones on south side of Ferris Mountains._________________ 8

IV. A, Tensleep sandstone forming the west side of Whisky Gap; 

B, Longitudinal view of steeply dipping Frontier sandstones 

on south side of Ferris Mountains._______._______-_--_- 8

V. A, Mesaverde escarpment on south side of Lost Soldier dome; / 

B, Mesaverde escarpment in northeastern part of T. 24 N., 

R. 89 W.; C, Table Hills from the northwest-.__--__ __ _ _ 26

VI. A, Adjacent portions of a complete section of the Mesaverde 

formation in sec. 33, T. 27 N., R. 89 W.; B, View across the 

G. P. oilfield, looking west ___________________._ 27

VII. Map of the Lost Soldier dome, showing areal geology and

structure of the Wall Creek sand.____-___-_---_---__--_ 34

VIII. Graphic logs of wells in the Lost Soldier-Ferris district-.-....... 34

FIGURE 1. Index map of Wyoming showing location of Lost Soldier area.. 6 » 

2. Map of the Ferris dome.-------------.------------------- 44

INSERT.

Page. 

Sections showing occurrence of oil and gas in Wyoming fields..--.---- 12
OIL AND GAS FIELDS OF THE LOST SOLDIERFERRIS DISTRICT, WYOMING.

By A. E. FATH and G. F. MOULTON.

INTRODUCTION.

The finding of commercial quantities of oil by drilling on the 

Lost Soldier Flats, in south-central Wyoming, during the spring of 

1916, marked the beginning of an oil and gas field development that 

has resulted in the discovery of the Lost Soldier, Ferris, Mahoney, 

G. P., Wertz, and O'Brien Springs fields, named in the order in which 

their productivity was proved. This district is generally referred 

to as the Lost Soldier-Ferris district, from the names of the two 

fields first discovered.

Surface indications of oil and gas are not to be found in the region, 

and it was not until geologists recognized the presence of welldeveloped domes in this district that the drilling of test wells was 

undertaken.

The oil'and gas fields of this district are in a high, barren, and 

practically unsettled region, in which most of the land still forms a 

part of the Federal domain. The need for classifying these lands 

in accordance with the public-land leasing act of February 25, 1920, 

resulted in an examination of the region by the United States Geological Survey during the summer and fall of 1920. The geologic findings 

of this examination were deemed sufficiently interesting to warrant 

their publication, and the present report is the result.

SUMMARY OF GEOLOGIC RESULTS.

The stratigraphy of the region is similar to that set forth in earlier 

reports on the oil and gas fields of the Big Horn Basin and central 

and east-central Wyoming. The rocks represented include crystalline rocks of pre-Cambrian age and sedimentary rocks that range 

from Cambrian to Tertiary. The rocks of greatest importance, 

because of their possible yield of oil and gas, belong to the Cretaceous 

system and include the Cloverly formation, with a sand identified 

as Muddy sand at its top; the Mowry shale; the Frontier formation, 

with the Wall Creek arid one to three other sands; and a producing 

sand that is thought to belong to the lower part of the Steele shale

1
2 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

or the upper part of the Niobrara shale. Although all these formations yield-either oil or gas or both within the district, they are not 

uniformly oil and gas bearing at all favorable localities. For instance, 

the Muddy sand yields oil in the Lost Soldier dome and gas in other 

places.

The pre-Cretaceous formations of the region also contain beds that 

could serve as reservoirs for oil and gas, and in other parts of the 

State oil and gas are found in some of these rocks. Strata that possibly contain oil and gas and lie within reach of the drill at some 

localities in the Lost Soldier-Ferris district include formations as 

low as the Madison limestone of Mississippian age.

The investigation determined that the Lost Soldier-Ferris district 

is an oil and gas area with rather sharply defined limits within which 

nine domes and anticlinal folds have been found. The district as a 

whole is the modified north end of the Rawlins uplift, a regional 

feature of major magnitude. The investigation has shown that most 

of the minor domes and anticlines that control the oil and gas accumulations in this district were formed at a much later date than the major 

Rawlins uplift, on which they are superimposed. The Rawlins uplift 

is of pre-Wasatch age, but the minor folds are of post-Wasatch age 

and perhaps may be as recent as post-Oligocene.

The outcropping formations are concealed by alluvial wash and 

windblown sand in a large part of the district. It has therefore been 

impossible to make an accurate structure contour map of the district except in small local areas. Of the nine minor upfolds that have 

been found, but two, the Lost Soldier and Bunker Hill domes, are 

sufficiently well indicated by the exposed rocks to show their general 

configuration and extent. The Lost Soldier dome yields oil from the 

Wall Creek and associated sands of the Frontier formation and from 

the deeper Mowry shale and the Muddy sand of Cleverly age. The 

Bunker Hill dome has not been adequately tested. The shallowest 

known oil-bearing stratum in this district lies at a depth of more 

than 5,000 feet on the Bunker Hill dome, and this alone can account 

for lack of immediate interest in testing the dome.

The Mahoney and Ferris domes are indicated by local exposures of 

Carlile and Niobrara shales encircled by the Steele shale, but present 

knowledge of their extent and configuration is based largely on information furnished by the drill. The Mahoney domes contain small 

quantities of gas in sands of Frontier age and large quantities of gas 

in the Muddy sand. The Ferris dome yields oil from the Mowry 

shale and large quantities of gas from the Muddy sand.

The locations of the Wertz and Sherrard domes are determined 

by dip and strike readings made on bedding planes in the Steele 

shale. The extent and configuration of their crests can not be 

determined except from information to be gleaned from future
FIELD WORK. 3

drilling operations. The Wertz "dome" contains small quantities of 

oil in the Mowry shale and large quantities of gas in the Muddy 

sand. Press reports seem to indicate that the Muddy sand contains 

also some oil. The Sherrard dome has been tested by two wells in 

which only a showing of oil was encountered. In view of the fact 

that the crest of this fold is concealed, it seems to the authors that 

the possibilities of this dome have not been sufficiently demonstrated 

by the test wells thus far drilled.

The O'Brien Springs anticline and the G. P. "dome" are indicated 

by rim-rock exposures of the Mesaverde formation. The crests of 

these two folds are completely concealed by dune sand. The O'Brien 

Springs anticline had been tested by but one well prior to February, 

1922, and in this well two good showings of gas were encountered in 

sands of the Frontier formation. The G. P. "dome" yields oil from a

sand that is considered to lie in the lower part of the Steele shale or 

the upper part of the Niobrara shale. Drilling operations thus far 

have not definitely proved the presence of "closure" on either of 

these folds.

The Separation Flats anticline probably represents the main axis 

of the Kawlins uplift as it extends northward across the Lost SoldierFerris district. Except in a very small area at its south end there 

are no rock exposures by which the location and configuration of 

.the axis can be ascertained. The anticline has been tested by five 

wells, in which only small showings of gas were encountered, but in 

the opinion of the authors these wells were not so spaced as to constitute an adequate test of the fold.

FIELD WORK.

The field work for this report was done between the middle of July 

and November 1, 1920, by a party that originally consisted of the 

two authors, N. W. Bass, and C. Y. Hsieh. The senior author was in 

charge until September 5, after which the work was carried on under 

the direction of the junior author.

The geologic mapping was done by means of plane table and telescopic alidade. After the measurement of a base line, an expanding 

system of triangulation points was established, from which secondary 

locations were made by the three-point method, supplemented here 

and there with stadia traverse. Altitudes were carried throughout 

the field by vertical angles and were based on United States Geological 

Survey bench marks, of which two lines cross the district. One of 

these lines crosses the southeastern part of the district and is described 

in a Survey bulletin.1 The other line, which is not described in any 

publication, extends along the southwest side of the district and is a

1 Results of spirit leveling in Wyoming, 1896 to 1912: U. S. Geol. Survey Bull. 558, pp. 36,40,1914.
4 .OIL AND GAS, LOST SOLDIER-FERBIS DISTRICT, WYO.

single-spur line run in 1907 by a United States Geological Survey 

party for use in classifying coal lands.2 The adjusted elevations of 

this line of bench marks are given on the map (PI. I). These two 

lines were tied in during the present investigation by vertical angles 

across the northern part of the district.

The formation boundaries and the positions and attitudes of key 

beds were mapped with accuracy where such information was vital, 

and at every point where a definite location was made the altitude 

also was determined. Detailed stratigraphic sections were measured 

at several localities, and by determining the intervals between key j* 

beds it was possible to draw structure contours (see PL I) throughout 

most of the district to represent the configuration of the top of the 

Wall Creek sand, which is the shallow producing sand on the Lost t 

Soldier dome.

The absence of key beds in some places and their concealment by 

alluvium and dune sand over considerable areas in others made it 

difficult and in places impossible to determine the geologic structure 

accurately. In some localities where shale without key beds is so 

exposed in natural outcrop or in pits dug by hand that its bedding 

planes could be determined, measurements of the dip and strike were . 

made, and these measurements are represented on the map by the . I 

usual dip and strike symbols. The value in critical localities of dip j 

and strike determinations is so great that in many places where rock f 

exposures are completely lacking several of the oil companies have 

dug shafts 20 feet or more deep through the alluvium and dune sand j 

to bedrock, in order to obtain a single strike and dip determination ', 

that would indicate the position or direction of a domal or anticlinal 

crest. Most of the shafts dug for this purpose were filled with sand 

at the time of this investigation and hence supplied no information 

for this report.

In the preparation of this report the senior author wrote most of 

the text and the junior author did most of the work of compilation 

for the structure and geologic map (PL I).

PREVIOUS GEOLOGIC INVESTIGATIONS.

,s The western and eastern marginal parts of the Lost Soldier-Ferris

district were investigated by the United States Geological Survey in 

1906 and 1907 to obtain data for coal-land classification, and the reports of these investigations 3 included maps showing the distribution ' 

of the formations in their respective regions.

It is probable that outside of these investigations no general examination of the region was attempted until, in the search by geolos Smith, E. E., The eastern part of the Great Divide Basin coal field, Wyo.: U. S. Geol. Survey Bull. 

341, pp. 220-242, 1909.

3 Veatch, A. C., Coal fields of east-central Carbon County, Wyo.: U. S. Geol. Survey Bull. 316, pp. 244-260, 

1907. Smith, E. E., The eastern part of the Great Divide Basin coal field, Wyo.: U. S. Geol. Survey Bull. 

341, pp. 220-242,1909.
U. S. GEOLOGICAL SURVEY

I Whisky Peak

EXPLANATION OF WELL SYMBOLS

Location derrick, 

or drilling well Abandoned test

or shallow 

assessment hole

SWKETV ZATJER

Js-Wertz dom

N.Y 

Ohio. 

P. R -

SEDIMENTARY ROCKS

Sh errand

Boulders and gravel

Mesaverde formation

Niobrara and Carlile shales

Frontier formation to Permian f ^

Red Beds"inclusive

Structure contours

on top of Wall Creek sand

interval 500 feet Pre-Cambrian

crystalline rocks Location essentially correct

(Based on adjacently mapped key bed or 

drilling information) Ssparaticn Flats

Location approximately correct

(Based on nearby key bed or drilling 

 information)

Location uncertain 

(Based on distant key bed information or 

on dip and strike determinations in shale)

Strike and dip

Location and in places even 

presence hypothetical

(Drawn to Jill ?'n space or basted on doubtful information)

Scale 125,000

BULLETIN 756 PLATE I

ABBREVIATIONS FOR 

NAMES OF WELLS

Col ___Columbia Oil Co. 

D__-_Dillon Oil Co.. 

D. O G_Diamond Oil and

Gas Co. 

D. W-_---Domino-Wyoming.

Oil Co.

- ____Emery Oil Co. 

E O __Eureka Oil Co. 

G C. W __Gate City-Wyoming

Oil and Gas Co. 

G. P -__General Petroleum

Co.

H O-__Hughes Oil Co. 

H. O. G__-Horseshoe Oil and

Gas Co. 

I. W. O _-Idaho-Wyoming

Oil Co.

Kas-_----KasomingOil Co. 

K. W--_- Kentucky-Wyoming

Oil Co. 

Miller. 

Midwest Refining

Co. 

New York Oil Co.

-.Ohio Oil Co.

-.Producers &. Refiners Corporation. 

Portland-Wyoming

Oil Co.

Sand Hills Development Co. 

Texas Co. 

Utah Oil and Refining Co.

---WashomingOil Co.

-..Wyo.-Kans. Oil

Syndicate. 

Wyanna Oil Co. 

_WyomassOil Co.

Strike and dip 

of overturned strata

R.89 W. R.88 W. R.87 W.

MAP OF THE LOST SOLDIEE-FERRIS DISTRICT, WYOMING

Showing the areal geology and structure of the Wall Creek sand
GEOGRAPHY. 5

gists for possible oil-bearing anticlines and domes, the presence of the 

Lost Soldier dome was recognized by a study of the map accompanying Smith's report. A test well proved the oil-bearing possibilities of this dome in the spring of 1916, and it is probable that 

commercial geologists immediately scanned the entire district. The 

results of their work, however, have never been published.

ACKNOWLEDGMENTS.

During the field investigation lodging and board were obtained at 

several ranches and drilling camps. These accommodations obviated the necessity of running a special camp or of driving out from 

Rawlins each day, and for this courtesy thanks are due to the ranchers 

and oil-company officials.

The officials and geologists of the oil companies were, as a rule, very 

generous in furnishing information regarding their wells and in discussing the geologic problems of the region. Geologic and development maps, together with well logs, were freely supplied. For such 

courtesies thanks are due to the following companies and officials: 

Bair Oil Co., C. A. Bonine, Columbia Oil Co., Emery Oil Co., General 

Petroleum Co., H. R. Harriman, Kasoming Oil Co., E. W. Krampert, 

Midwest Refining Co., Ohio Oil Co., Portland-Wyoming Oil Co., 

Producers & Refiners Corporation, Sand Hills Development Co., the 

Texas Co., Carroll M. Wagner, Wasatch Oil Co., R. E. Wertz, Wyanna 

Oil Co., and Wyoming-Kansas Oil Co.

The writers are especially grateful to Messrs. E. W. Krampert and 

C. A. Bonine for much detailed information and for their discussion 

of local geologic problems with which they alone were intimately 

familiar. The mapping of the sandstone bed in the upper part of 

the Steele shale across Range 86, on the flanks of the O'Brien Springs 

anticline., was supplied by Mr. Bonine.

The painstaking work of Mr. N. W. Bass in the field and in compiling a map of the Ferris dome area is gratefully acknowledged, and 

to Mr. Willis T. Lee thanks are due for detailed stratigraphic data 

which enabled the writers to make correlations with the sedimentary 

section of southeastern and east-central Wyoming.

GEOGRAPHY.

LOCATION AND ACCESSIBILITY.

The Lost Soldier-Ferris district is roughly triangular and contains 

about 455 square miles. It is in the northeast corner of Sweetwater 

County and the northwestern part of Carbon County, in southcentral Wyoming. (See fig. 1.) It is most easily reached from 

Rawlins, 25 to 40 miles to the south, a division point on the Union 

Pacific Railroad and the county seat of Carbon County. The dis-
 6 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

trict can also be reached from Casper, 85 miles to the northeast, 

on the Chicago, Burlington & Quincy and Chicago & Northwestern

 railroads, and from Lander, the terminus of the Chicago & Northwestern Railway, about 100 miles to the northwest.

Rawlins, with a population of about 4,000 (3,969 in 1920), is the 

nearest and most accessible railroad point and is therefore the supply

 center for the entire district. Outside of Rawlins there is no place 

where meals and lodging can be obtained except at the camps of 

the oil companies or at the few scattered ranches.

SHAKtiE j

 I ( jrmdpdlis \

FIGURE 1. Index map of Wyoming showing location of Lost Soldier area. 

TOPOGRAPHY.

The Lost Soldier-Ferris district occupies the almost isolated east 

 end of the Great Divide Basin, a high interior basin having no outward drainage, which lies between the two low divides that in this 

region represent the Continental Divide. Within the district this 

basin -has a minimum altitude of about 6,420 feet at Boundary Lake 

and is nearly encircled by the Green, Ferris, and Seminoe mountains 

on the north and northeast, the Table and Haystack hills on the 

east and southeast, and the Rawlins Hills on the south. To the west 

the hogback escarpment rim of Mesaverde sandstone almost isolates 

the Lost Soldier-Ferris district from the main part of the Great 

Divide Basin, lying farther west. The Ferris Mountains on the north
GEOGRAPHY. . 7

form a striking topographic feature, and their highest peak rises 

Above 10,000 feet. (See PL III, A.)

The Ferris Mountains are separated from the basin proper by the 

valleys of Muddy and Sand creeks, which after leaving the area flow 

northward to join Sweetwater River. Outside of these valleys the 

basin has a smooth floor, which, however, in general rises very gently 

toward the northeast. The larger lakes in the basin lie in the southwestern part. The upward slope toward the northeast may be ao

 counted for in part by the great blanket of wind-transported sand that 

covers this part of the district. (See PI. II, A, B.) The source of 

this sand is to be found principally in the Tertiary sedimentary rocks 

that cover the surface to the west of this district, and the present 

position of the sand must be ascribed to the prevailing southwesterly 

winds. The continued accumulation of this sand has undoubtedly

slowed down the erosion of this part of the district and thus caused 

the present northeasterly upward slope of the basin floor.

WATER SUPPLY.

The perennial streams of the district are limited to Muddy Creek 

.-and its mountainward tributaries and the headwaters of a few other 

drainage channels that head in the mountains at the north side of the 

district. During wet seasons and immediately after hard rains these

 channels carry the run-off toward the low spots of the basin, where 

there are several more or less alkaline lakes. The subsurface drainage along some of these channels is the source for the water supply of 

the camps and drilling operations.

Springs are found at a few places and are a boon to the industrial 

needs of the region, as well as to the traveler and to the livestock 

that grazes in the basin. Some of these springs supply sufficient 

water to fill small artificial ponds, and from these the water is piped 

for considerable distances to points where wells are being drilled.

There are numerous local depressions in the basin, and these range 

from those which contain water for only a few days after rainy spells 

and thereafter are simply dry lake beds to those in which the water 

is perennial and highly alkaline. Some of the alkaline lakes when 

nearly or completely dry present glaring white salt crusts and boggy 

bottoms. Several of these lakes are not shown on the map (PI. I) 

because they do not lie in or near the localities where the geology was

mapped.

VEGETATION.

The basin proper is an arid desert where the precipitation is very 

slight during the summer and where the snows of winter are insufficient to modify the desert character. The land surface sustains a 

small amount of vegetation, most of which consists of sagebrush. 

During relatively wet years the growth of grass is sufficient to support 

a few flocks of sheep and small bands o rattle and horses.
8 OIL AND GAS, LOST SOLDIER-FEERIS DISTRICT, WYO.

CULTURE.

The roads that connect the district with Rawlins, Casper (through 

Whisky Gap), and Lander are comparatively good, and those to Rawlins, over which most of the oil-field freight is carried, receive occasional attention in the way of grading and upkeep. Practically all the 

travel and hauling is done by automobile and motor trucks. The 

roads that connect the different fields and camps and especially the 

secondary roads in the sand-covered areas are not in permanent 

locations but are changed with the season or at the will of the travelers.

Prior to the advent of oil operators the only industry in the district 

consisted of a little stock and sheep grazing, such as the vegetation 

would sustain, combined with ranching in a few favorable places.

In the search by geologists for possible new oil fields the Lost 

Soldier dome was naturally the first to be found, as it is the only one 

in the district to be well delineated by an encircling rim of sandstone hogbacks. Soon after this dome had been proved to contain oil 

the entire district was combed for other favorable drilling localities t 

and this work resulted in the discovery of additional domes and anticlines. Drilling camps were soon established at many places in the 

district, old roads were improved, new ones were built, and now hundreds of people are living in this district where before a few ranchers 

and sheep herders constituted the entire population.

Early in the spring of 1919 a 4-inch pipe line was laid from the 

Union Pacific Railroad at Fort Steele to the Lost Soldier field, and 

in the fall of 1920 a second line paralleling the first from Fort Steele 

to a point near Boundary Lake was laid to the Ferris and G! P. 

fields. (See PI. I.) In the fall of 1921 a pipe line 90 miles long was 

laid between the district and Casper to supply the refineries there 

with gas.

MARKETS FOR OIL AND GAS.

The law of supply and demand affects petroleum and natural gas 

very differently. The differences are largely inherent in the nature 

of the substances but depend also on the distance between the oil 

and gas fields and the markets. Petroleum can be stored and refined 

into hundreds of different products, and these products in turn can 

be stored, so that the interval between the time of production at the 

well and the time of consumption may range from a few weeks ta 

many years. The refining and storing operations thus occupy what 

may be termed an elastic interval between production and consumption. For natural gas, on the other hand, no such elastic interval 

is possible. As storage is not.feasible the gas takes an almost direct 

course from well to consumer, and the time between production and 

consumption ranges from a few minutes to a maximum of only a few 

days where it is transported to distant cities through long pipe lines.
U. S. GEOLOGICAL SURVEY BULLETIN 756 PLATE II

A. SAND DUNES IN SEC. 36, T. 25 N., R. «7 W.

B. LARGE EXPOSURE OF BEDROCK SHALK IN THE SAND-COVKRKD REGION.

C. WHISKY (JAP, CUT THROUGH TENSLEEP SANDSTONE. 

Granite Mountaias in the distance.
U. S. GEOLOGICAL SURVEY 

.1. FERRIS MOUNTAINS. 

The prominent walls in the left middle distance are formed by the steeply dipping sa

li. WALLS OF STEEPLY DIPPING FRONTIER SANDSTONES O\ SO
II. S. GEOLOGICAL SURVEY 

.4. TENSLEEP SANDSTONE FORMING THE WEST SIDE OF 

WHISKY GAP.

JJ. LONGIT

ST
STRATIGRAPHY. 9

In densely settled regions containing manufacturing industries, such 

as the Appalachian region, natural gas is at a premium because of 

the nearness of its market, and as a result an average gas field in 

such a region may be more valuable to its owners than an average 

oil field, but in the thinly settled State of Wyoming the opposite 

is usually true.

In the Lost Soldier-Ferris district it was profitable to build storage 

tanks for the oil and to lay a pipe line to conduct it to the railroad at 

Fort Steele, from which it could be transported by tank cars to 

existing refineries, but until the winter of 1921-22 no such procedure 

was possible for the gas, and as a result a gas well was a liability 

instead of an asset except as the gas was used in drilling wells and 

for heating and lighting the camps.

The town of Kawlins, with its railroad shops, was the first market 

suggested for the gas from the Lost Soldier-Ferris district, but the 

quantity that could be marketed there was reported to be too small 

to pay a return on the investment required for the necessary pipe line. 

Larger towns, such as Laramie and Cheyenne, were even more distant 

in relation to the size of the market which they could furnish, and 

hence pipe lines to reach these cities were not to be considered. Not 

until the fall of 1921 -was there any movement toward the creating 

of a large and reliable market for the gas. At that time two of the 

larger companies operating in the district combined their interests 

and laid a pipe line to Casper, where the gas is supplied to several 

large refineries.

As the gas from the Wertz and Ferris fields contains the heavier 

vapors, which condense into gasoline, the erection of gasoline-extraction plants should be a profitable enterprise, and now that the pipe 

line mentioned above is completed a large supply is available for 

gasoline extraction without waste.

STRATIGRAPHY.

GENERALIZED SECTION.

The rocks exposed within the oil and gas fields of the Lost SoldierFerris district represent the Cretaceous and Quaternary only, but 

the stratigraphic column including the areas that immediately border 

these fields contains formations that range from the Carboniferous to 

late Upper Cretaceous and also pre-Cambrian crystalline rocks 

The entire section is well exposed, and nearly complete sections can 

be studied within reasonably small areas. Except in a few places the 

different formations are rather uniformly developed throughout the 

district. The principal characteristics of these formations are given 

hi Table 1. More detailed descriptions of the formations, including 

several measured sections, are given in the pages following the table.

The relation of the stratigraphic section and producing strata of 

the Lost Soldier-Ferris district to those which have been described 

for other parts of Wyoming is given in Table 2, opposite page 12.
10 OIL AND GAS, LOST SOLDIEE-FEKRIS DISTRICT, WYO. 

TABLE 1. Generalized stratigraphic section in the Lost Soldier-Ferris district.

Age.

Quaternary.

(?)

Dretaceous.

Group.

Montana.

Colorado.

Formation.

Alluvium and

wind-blown 

sand.

(?)

Lewis shale.

Mesaverde formation.

Steele shale.

Niobrara shale.

Carlile shale.

Approximate

thickness

(feet).

Not measured.

680

200-2,200

4,000 to 4,750

1,425-1,600

General characteristics.

The alluvium consists principally

of worked-over material from the

surrounding formations. The

wind-blown sand is probably derived from the Tertiary formations that crop out west of the

district.

Yellowish-brown and white massive and thin-bedded sandstones 

interbedded with brown, grav,.

and black shales.

Principally dark-gray, thinly laminated shale containing several'

beds of yellowish-brown sandstone from 1 to 20 feet thick. Marine fauna. The thickness given

was measured inT. 25N., R. 89 W.

Generally characterized by three

divisions described below. Varies greatly in thickness, from

1,700-2,200 'feet where believed to

be normally developed down to

200 feet or less (probably a local

condition). Nonmarine and marine faunas.

1. Thick sandstone beds interbedded with equally thick series 

 of alternating thin beds of sandstone and shale. A white sandstone about 100 feet thick (Teapot 

sandstone member) generally Ties 

at or within a few hundred feet of

the top. Coal-bearing locally. 

 Forms ridges and escarpments.' 

2. A thick mass of dark-gray to

brown shale, sandy shale, and

light'gray to yellowish and reddish-brown sandstone with a few

layers of brown limy sandstone.

Presents in places a striking

banded appearance. Forms a

surface of low relief.

3. Thick sandstone beds interbedded with equally thick series 

of alternating thin beds of sandstone and shale. Forms ridges

and escarpments. In this report 

the lowermost thick white sandstone is considered the base of the

formation.

Mainlv dark-colored soft shale with

thin zones of sandy shale and

sandstone. The upper part is

relatively more sandy and is

transitional into the overlying

Mesaverde formation. At about

1,500 feet below the top (in

some localities the formation is 

considered to be subnormally

developed and the interval where 

measured is but 960 feet) is a 50-

foot sandstone bed that appears

to be persistent throughout a

large area. Marine fauna, with

some brackish-water forms in

upper part.

Top marked bv a scries of verv thin 

beds of hard, comparatively resistant yellow limestone which

shows a wavy lamination on

weathered surfaces, interbedded

with soft argillaceous sandstone

and shale. The main body of the 

mass is composed of dark-gray

thin-bedded shale. Marine fauna.
STRATIGRAPHY. 11

TABLE 1. Generalized stratigraphic section in the Lost Soldier-Ferris district 

Continued.

Age.

Cretaceous (?).

Jurassic.

Triassic and 

Permian.

Pennsylvanian.

Mississippian.

Cambrian.

Pre-Cambrian.

Group. Formation.

Frontier formation

Mowry shale.

Thermopolis shale.

Cloverly formation

Morrison formation.

Sundance formation.

Bed beds.

Tensleep s a n dstone.

Amsden formation.

Madison limestone.

(?)

Crystalline rocks.

Approximate 

thickness 

(feet).

263-705

200-300

50-135

75-180

400-700

150-175

210

165

395

General characteristics.

Uniformly characterized at its top 

by two to five beds of compara>- 

tively resistant light-colored 

sandstone and interbedded shale, 

below which is several hundred' 

feet of soft shale . The sandstones 

dip steeply and form strikingwalls a few hundred feet high.

Hard fissile dark-gray shale, which, 

weathers light colored; contains 

abundant fish scales. The formation is resistant in comparison. 

with the overlying shale . Marine 

fauna.

Soft dark-gray shale.

Characterized by a hard resistant 

light-colored conglomerate or 

quartzitic sandstone bed, 25 to75 feet thick, at its base. In. 

places this is overlain by 100 to> 

150 feet of shale, followed by & 

hard quartzitic sandstone about 

28 to 35 feet thick.

Interbedded varicolored shale,, 

yellow to light-gray soft sandrstonc, and a few thin beds of 

fossiliferous limestone. The shale 

and sandstone in the upper 

part (chiefly Morrison) vary 

greatly in character and compostfor the limestone beds, which are 

not everywhere exposed, these 

formations, for general purposes,, 

can be described merely as the 

interval between the conglomerate at the base of the Cloverly 

formation above and the Triassicand Permian red beds below.

Bed sandstone, red sandy shale, 

and red shale, all rather soft, withi 

one conspicuous thin light-gray 

limestone near the middle; conspicuous because of the deep-red! 

color. At the base several thim 

beds of impure cherty gray limestone interbedded with deep-redl 

shale and sandstone.

Massive to thin-bedded and crossbedded resistant sandstone, locally quartzitic.

A series of limestone, sandstone , and', 

shale; lower part notably red.

Limestone; some layers sandy and. 

in places of quartzitic character.

Quart zite.
12 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO. ' 

PEE-CAMBBIAN CRYSTALLINE BOCKS.

!

The oldest rocks of the Lost Soldier-Ferris district are found in \ 

the Seminoe Mountains, at the northeast side of the district, where ( 

the basement crystalline rocks of these mountains are brought up ' i 

by faulting against the Cretaceous formations. Hares 4 considers 

the crystalline rocks of the Granite Mountains, 20 miles to the north 

of this district, to be pre-Cambrian, and it would seem that the 

crystalline rocks of the Seminoe Mountains are equally old. The 

age of these crystalline rocks is not pertinent to the present paper, \ 

except for the fact that they formed a part of the basement upon 

which all the sediments of the region were deposited and are therefore the oldest rocks of the district.

Indications of oil have been reported as occurring in pre-Cambrian 

granite on the south side of Copper Mountain, in northeastern 

Fremont County, Wyo.,5 but without doubt this is an anomalous 

occurrence, and hence does not signify a possibility of finding oil in 

the pre-Cambrian crystalline rocks of the Lost Soldier-Ferris district.

CAMBRIAN QUARTZITE.

In the Ferris Mountains and the Rawlins Hills an unnamed 

quartzite of Cambrian age overlies the basement granite. It is pink 

to gray and in the vicinity of Rawlins is 395 feet thick.6 It is conglomeratic in its lower part and at several other horizons at various 

intervals up to its top. The upper part contains ripple marks and 

worm trails.

Indications of oil in similar quartzite have been observed on the 

south side of Copper Mountain, 7 presumably in a locality near that 

where indications are reported to occur in the underlying granite. 

The two occurrences are possibly related in some way. It does 

not seem that either of these occurrences should indicate that oil 

may be found in similar rocks in the Lost Soldier-Ferris district.

MISSISSIPPIAN ROCKS. 

MADISON LIMESTONE.

, The Cambrian rocks of the Ferris Mountains and the Rawlins Hills 

are overlain by the Madison limestone of Mississippian age. Some 

of the layers of this formation are sandy and in places approach a 

quartzite in composition. Its thickness at one place in the Rawlins 

Hills is 165 feet.

< Hares, C. J., Anticlines in central Wyoming: U. S. Geol. Survey Bull. 641, p. 250,1916.

 Trumbull, L. W., Petroleum in granite: Wyoming Geol. Survey Bull. 1, pp. 1-16,1916.

6 This formation and the overlying Madison and Amsden were examined and measured in the Rawlins 

Hills by W. T. Lee, who kindly supplied the data for use in this report.

i Fisher, C. A., and Calvert, W. R., The oil and gas fields of Wyoming (unpublished U. S. Geol. Survey 

report, prepared in 1912).
TABLE 2. Sections showing occurrence of oil anc gas in Wyoming fields. ; 

[Correlations approximate and sections incomplete, o, Good showings or small production of oil; O, good commercial production of cil; g, good showings or small production of gas; G, good commercial production of gas; +, oil seepage. , : '

' -System or series.

Tertiary (Eocene).

Tertiary (?) (Eocene?).

Upper Cretaceous.

Lower Cretaceous.

Jurassic.

Triassic.

Permian.

- Pennsylvanian.

 Missis'sippian.

Group.

Montana.

Colorado.

Southwestern Wyoming.

Spring 'Valley.a

Wasatch.

Evanston.

Absent.

Absent.

[Adaville?].

Hilliard.

Frontier.

Aspen, o

Bear River, o 

Absent. .

Beekwith.

Twin Creek.

Labarge.6

Wasatch. +

Evanston.

Absent.

Adaville.

Hilliard.

Frontier.

Aspen. +?

Bear River.

Carboniferous

Baxter Basin.c

Wasatch.

'Post-Laramie."

'Laramie."

Lewis. 

Mesaverde.

___ (?) 

Baxter.

Not exposed.

Frontier. G o

Aspen. .

[Dakota. G o] 

Absent.

Beekwith.

Twin Creek. 

Nugget.

Ankareh. 

Thaynes. 

Woodside.

Phosphoria.

Weber. 

Older Pennsylvanian.

Mississippian.

Southwest side of Big Horn Basin.

Shoshone.rf

Wasatch.

Fort Union.

Lance.

Meeteetse. 

Mesacerde.

Cody.

Frontier, c

Mowry. o

Thermopolis 

og

Cloverly. g

Morrison. g

Sundance. 

Chugwater.

Enibar.

Tensleep. 

Amsdenr

Madison.

South Oregon 

Basin.e

Wasatch.

Fort Union.

Lance.

Meeteetse. 

Mesaverde.

Cody.

Frontier, o g

Mowry.

Thermopolis. 

GO

Cloverly. G

Grass Creek./

Mesaverde.

Cody.

Frontier. O g

Mowry.

Thermopolis. 

G

Cloverly.

Morrison. o«n

Sundance.

Chugwater.

Embar.

Hamilton. #

Mesaverde.

Cody.

Frontier.

Mowry.

Thermopolis.

Cloverly.

Morrison.

Sundance.

Chugwater. O

Embar. O

Golden

Eagle.'*

G

Warm 

Springs .«

-

Frontier.

Mowry.

. Thermopolis.

Cloverly.

Morrison.

Sundance.

Chugwater.

Embar. O

Tenslesrj. 

Amsden.

Madison.

Northeast side of Big Horn Basin.

Hidden 

DomeJ

G

Torchlight.*

,

Frontier.

Mowry. O

Thermopolis. 

g

Cloverly. .

1

Lamt .1

Cody.

Frontier; o G

Mowry. o g

Thermopolis".

t

f. 

Cloverly. .

Greybull. 

Frontier.

Mowry. o g

Thermopolis 

g

Cloverly. OG

. "

. 1

'

-

-

Sheep Mountain 

Anticline."

"Red Beds."

Pennsylvanian.

Madison, -i- '

Crystal 

Creek./

O

o

Byron.o

Gebo.

Cody. G

Frontier.

Mowry.

Thermopolis.

Cloverly.

Morrison.

Sundance.

^

Garland.?

Judith River.

Claggett.

Eagle.

Nicbrara. -

Carlile.

Frontier, o g

Mowry.

Thermopolis.

Cloverly. G

Morrison. G

Elk Basin.g

Wasatch.

Fort Union.

Lance. 

Bearpaw.

Judith River.

Claggett.

Eagle.

Niobrara.

Carlile.

Frontier. O

Mowry.

Thermopolis.

Cloverly.

Morrison.

Sundance.

Chugwater.

Embar.

*

, Wind River Basin.

Maverick 

Springs.'-

Wind River.

Absent.

Mesaverde.

Cody.

Frontier.

Mowry.

Thermopolis. 

1

Cloverly.

Morrison.

Sundance.

Chugwater. +

Embar. O

Amsden.

Madison.

Pilot Butte.s

Wind River.

Absent.

Mesaverde.

Cody: 

Pierre. O

Niobrara.

Unnamed shale member of Benton.

Frontier.

Mowry.

Thermopolis. 

Dakota.

Fuson. 

Lakota.

Morrison.

Sundance.

Chugwater.

JEmbar.

Amsden.

Madison.

Dallas.*

-

Mesaverde.

Mancos. 

Dakota.

Lower Cretaceous.

Morrison.

Sundance.

Chugwater. O+

Enibar. O 

Tensleep. o oo

Amsden.

Madison. ,

Derby 

Dome."

O?

O

Big Sand 

Draw.",

Wind River.

Absent.

Mesaverde.

Steele.

Niobrara.

Carlile.

'.Frontier. G

1

^

South-central "Wyoming.

i

Lost Sole ier.«>

Lewis.

Mesaverde.

Steele.

Niobrara.

Carlile.

Frontier. - O j

Mowry. o

Thermopolis. 

M

Cloverly. SI

C<

Mornson.

Sundance.

Triassic and 1 

beds.

Tensleep.

Amsden.

Madison, 

i

-' : ' . " '--.Tr'"--- ' ' ' : ~ - - - -TV-,- . * Hewett D F and Lumen C T op cit pp 75 77 t Woodruff, E. G., The Lander oil field, Wyo.: U. S. Geol. Survey Bi 

oVeateh, A. O., Geography and geology of a portion of southwestern Wvoming, with special reference to coal and oil: U. S. Geol. Survey Prof. Paper 56, pi. 3, 1907. zidem r>' 7°" '' ' '" "' ' f-*'- « Trade journal reports. 

*> Schultz, A. R., The Labarge oil field, central Uinta County, Wyo.: U/S. Geol. Survey Bull. 340, pp. 364-373, 1908. ' - mldem' r>' 6l" s" « Collier, A.' J., G^s in the Big Sand Draw antichne, Fremont County, 

c Schultz, A. R., Oil possibilities in and around Baxter Basin, in the Rock Sprirgsup^, Sweetwater County, A^ . « Wash'burne", C. W., Gas fields of the Big Horn Basin, Wyo.: U. S. Geol. Survey Bull. 340, p. 361, 190S. . ' wThisreport ,,-,,, .,._._, . 

d Hewett, D. F., and Lupton, C. T., Anticlines in the southern part of the Big Horn Basin, Wyo.: U. S. Geol. Survey Bull. 65o, pp. 186-lbS, 1917. * Q zioo.ler yWor TV,- Bvron o'l and "as field Wyo Wyoming; Geol Survey Bull 14, pp. 200, 201, 1917. z Hancock, E. T., unpublished report. Lee, W. T., personal commun 

*Idem,p.lSS. ,.." " ' . t, Emery, W^B.', unmiblishcdVeponfon Wyoming oil and gasfields. * . v Heald, K.C '. , The oil-bearing horizons oT Wyoming : Am. Assoc .Pet 

/Idem, pp. 153-156: Heald, K. C., personal communication. - ' . , - ,__,,. , , ± -ar, ' oTTnrpsO 1 ThpFlkBa-4n oilfield Wvaminc and Montana: U S Geol. Survey Bull. (in preparation). z Emery, v\ . B-, Unpublished report on Wyoming oil and gasfields. 

a Collier, A. X, Oil in the Warm Springs and Hamilton domes; near Taerm9polis,-Wyo.: U. S- Ge,ol. fiurvqy Bull. 711, pp.-Sl-73, 1010. - Emery, W. B., Unpubhshed report on Wyom- ? cdlfer \ 3 Irlticli^es near Maverick Sprin-s. Fremptit County, Wyo.: U. S. Geol. Survey Bull. 711, -op. 149-168, 1919. aa Wegemann. C. E., The Powder River oil field, Wyo.: U, S. Geol. £ 

ing cil and gas fields. Hewett," D. F., personarcommunication. . - '- ' - ' -sne^er' Victor* The Pilot Buttc oil field- Wyoming Geol. Survey Bull. 13, p. 169, 1616. " i " gasfields. Heald, K. C-, personal communication. 

h Collier, A, J.,'persorjal communication. ' . .- ' " ^ ' ' 

i Collier, A- J.', Oil in the,Warm Springs and Hamilton domes, near ThermopoliSj Wyo.: U. S. Geol. Survey Bull. 711, pp. 61-73, 1919. 

i Lupton, C. T., pers'ctoal-comniunicati.oi;. * -"-' . v -

i

liddy. O

iple.

>Hglomerate.

!

r- ermian red

i

t

Ferns Dome.w

Mesaverde.

Steele.

Niobrara.

Carlile.

Frontier.

Mowry. O

Thermopolis. 

Muddy. G -

Cloverly.

Morrison.

Shale.

Conglomerate.

G. P. Dome."1

Mesaverde.

Steele. 

O ?

Niobrara.

Carlile.

Frontier.

Mowry.

Thermopolis. 

Muddy.

Cloverly. Shale.

Conglomerate.

i 

i

Sundance.

Triassic and Permian red 

beds.

Amsden.

Madison.

 Rock Creek.*

Hanna.

Absent. 

Lewis.

Mesaverde.

Steele.

Niobrara.

O

Benton. Mowry.

o (First Muddy) 

O (Second Muddy)

Cloverly. 

O (Third Muddy)

Morrison.

Sundance.

Chugwater.

Forelle.

Satanka.

Casper.

 East-central Wyoming. i.

Bolton Creek.y

'

Dakota (?).

Lower Cretaceous.

Shale.

Conglomerate.

Morrison. '

Sundance. 6

Chugwater.

Embar. ' O?

Amsden.

Madison. -

Poison Spider.?

Fort Union.

Lance.

Mesaverde.

Steele.

Niobrara.

Carlile.

Frontier.

Mowry.

Thermopolis.

[?]

Lower Cretaceous conglomerate. O

Morrison. o

Sundance.

Chugwater.

Embar.

Powder 

River.*

Lance. 

Lewis.

Mesaverde.

Steele. G

Mowry.

Thermopolis.

Dakota (?).

Morrison.

Sundance.

Chugwater.

Embar. -

Tisdale.ao

Mesaverde.

Steele.

Niobrara.

Carlile.

Frontier.

Mowry. 4-

Thermopolis.

Dakota (?). 4-

Morrison. + 

Sundance. +

Chugwater.

Madison.

Salt Creek.66 -j

Wasatch.

Fort Union.

Lance. j

Lewis. [

- t

Mesaverde. i

Steele. -f O | -

Nio~brara. +O

go

Benton. Mowry.

1

i 

1

V')

OH j" 

Cloverly. \

Morrison.

Sundance.

Chugwater.

 -rt

,

11. 452, p. 27, 1911; Heald, K. C., personal communication. bb Wegemann, C. H., The Salt Creek oil field, Wyo.: U. S. Geol. Survey Bull. 670, pn. 27 39, 1918 

1. " <* Emery, W.B., unpublished report on Wvoming oil and gas fields. Heald. K.C., The oil-bearing horizons of Wyoming: 4m 

Wyo.: U. S. Geol. Survey Bull. 711, pp. 75-83, 1919. 5, No. 2, p. 200, 1921.- " 

i " ^Hancock, E. T., The Lance Creek oil and gas field, Niobrara County, Wyo.: U. S. Geol. Survey Bull. 716, pp. 91-122. wo. 

icatjon. ee Darton, N. H:, The structure of parts of the central G-reat Plains: U. S. Geol. Survey Bull. -691, pp 24-26, 1G1S 

rpleam Geologists Bull. 5, No. 2, p. 191, 1921: and personal communication. if Hancock. E. T., The Mule Creek oil field, Wvo.: U. S. Geol. Survey Bull-. 716, pp. 35-53 19'0 Lee, W. T-, unpublished report. - gg Collier, A." J., The Osage oil field, Wesson County. Wya;: U. S,. Geol. Survev Buy. 730, pc.-71-UO, 19W 

urvey Bull. 47j, pp. 56T75, 1912. Emery, W. B., unpublished report on Wyoming oil and *)* Hancock, E. T., The Uptou-Thoimoa-oil field, Wvc.: U." S. Geol. Survev- Bull. 716, np. 17-34. 19^0 """

Teapot.&fci

Wasatch.

Fort Union.

Lance.

Lewis.

Mesaverde.

Steele. +o

Niobrara.

O 

OG

Benton. Mowry.

Cloverly.

Morrison.

Sundance.

 *

,-

Big Muddy. <=c

Lance. 

Fox Hills.

Pierre. 

O

O

Benton.

Cloverly.

Northeastern Wyoming.

Lance Creek.**

Lance.

Fox Hills. 

Pierre.

Niobrara.

Carlile. +g

Greenhorn.

Graneros.

Shale.

Mowry.

Shale.

Newcastle"*"*

Shale.

Fuson.

Lakota. O ?

Morrison. Morrison.

Sundance. Sundance.

Old Woman."

Pierre.

Niobrara.

Carlile.

Greenhorn.

Graneros.

Fuson.

Lakota.

Mule Creek.//

Niobrara.

Carlile.

Greenhorn.

Graneros.

Fuson.

Mowry.

 Newcastle.

Lakota. O

Morrison. j Morrison.

Sundance.

"Red Beds."

Minnekahta .

Opeche.

Minnelusa. o

Pahasapa.

Sundance.

Spearfish.

Minnekahta.

Opeche.

Minnelusa.

Pahasapa. , .

Os3.gQ.3S

. Lance.

-Fox Hills. 

Pierre. -

Niobrara.

Carlile. o

Greenhorn

Graneros.

. o

B elle Fourche + o

Mowry. o

Nefsy.

Newcastle. O

Skull-Creek, o

Dakota, o g 

Fuson. .

Lakota.

Morrison.

Sundance.

Spearfish.

Minnekahta.

Opeche.

Upton-Thornton .fifc

Pierre.

Niobrara.

Carlile. O

Greenhorn.

Graneros.

Shale.

Mowry.

Shale. -

Sandstone.

Shale.

Dakota. , 

Fuson.

Lakota.

Morrison.

Sundance.

Spearfish.

Minnekahta.

. | Opeche.

Minnelusa.

Pahasapa. :

:.' _ , . ,, . . ,. ^ , n'Barnett, V. H., The Mooreroft oil field, Crook County. Wyo.: -U.S. Geol 

Assoc. Petroleum Geologists Bull. jj Collier, A. J., personal communication, 

i-i Press reports. 

ll Wegemann, C. H., Personal communication. 

mm Hancock reported the main production" of oil and gas to come from the "N 

and possibly Lakota. This later information is based on personal communicatic 

«fl Well completed, in 1920. Personal comraunicatioa from D. F. Hewett 

oa Estabrobk, E. ~L., personal communication.

. Survey Bull. 581,

ewcastle sand, but 

ms from C. J. Hare

Minnelusa.

Pahasapa.

pp. 83-104,

more recen 

s, C. T. Lup

Moorcroft."

Fox Kills. 

Pierre.

Niohrara.

Carlile.

Greenhorn.

Stole.

Morry. o

Graneros. Saridstone.

Shale.

Dakota, o

Euson. -fLatota.

Morzison.

Sundance.

Spearfish.

Minnekahta.

Opeche.

Minnebusa.

ZRocky-

 ,

 

-+ o

1914; Heald, K.- C.; personal wmmunieation.

c information indicate? it to cometoDit'lie Dateota 

ton, and CarrpJl ]£. Wegemacu.

79079 24. (Face p. 32 J

\
STRATIGRAPHY. 13

The Madison limestone has been reported to contain oil in Sheep 

Mountain Canyon, in the Big Horn Basin (see Table 2), and in 1921 

it was found to be oil-bearing in the Soap Creek field, in southern 

Montana. 8 This discovery makes it necessary to consider the 

possibility that this formation is oil-bearing in the Lost SoldierFerris district. The Madison lies within reach of the drill in the Lost 

Soldier and Ferris domes and perhaps also in the Mahoney dome, 

where it probably lies at depths ranging from about 4,400 to 5,000 

feet. (See Table 3, p. 29.) It should certainly be tested in at least 

one of these localities.

PENNSYLVANIA^ BOOKS. 

AMSDEN FORMATION.

Above the Madison limestone and below the Tensleep sandstone

is a mass of limestone, sandstone, and shale that measures about 

200 feet in thickness and represents the Amsden formation, which 

in this area is largely if not wholly of Pennsylvanian age. Its lower 

portion is notably red.

Section of lower part of Amsden formation measured in the Rawlins Hills, about 8

miles north of Rawlins.

Feet.

Limestone, covered in part_-____-__-_---_--__---_________ 42

Covered interval._-___.-___-_-___--____________-_.-__.__ 70

Limestone, gray_______.______________.___.___.______..__ 12

Limestone, gray to pink, containing considerable red chert. 

The lower 10 feet is chiefly red chert.___________________ 46

Sandstone, red, and interbedded red shale. In some places 

the lower sandstone is quartzitic________________________ 40

The Amsden is not known to be oil-bearing at any place in Wyoming, but in the Soap Creek field, in southern Montana, it is the 

formation from which several of the wells obtain their oil. It has 

been thought by those who have worked in that field that the oil 

found in the Amsden formation is fed to it through upward migration along faults from the underlying Madison limestone. 8 A test of 

the Madison limestone in the Lost Soldier-Ferris district will also be 

a test of the Amsden.

TENSLEEP SANDSTONE.

The Amsden is overlain by the distinct and massive Tensleep 

sandstone. This sandstone is well exposed at Whisky Gap, in sec. 

13, T. 27 N., R. 89 W., a few miles north of the district represented 

on Plate I, where it forms the narrowest part of the gap. It is also

8 Thorn, W. T., jr., personal communication. 

79079 24f 2
14 . OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

well exposed near Bell Springs, to the south, where it outcrops west 

of the Rawlins road in the south half of T. 23 N., R. 88 W.

At Whisky Gap (Pis. II, A; IV, A) its thickness is between 150 and 

175 feet and it consists of thin to thick bedded resistant rock composed of medium-sized grains of fairly pure quartz. It is also crossbedded and slightly quartzitic, and as it is rather porous, it should be 

an excellent reservoir rock for either gas, oil, or water. In color it is 

white, with yellow and tan shades on the weathered surfaces.

The Tensleep sandstone contains oil and gas at several places in 

Wyoming, although its capacity for commercial production has thus 

far not been very marked. Its uniform development throughout 

large areas and its general porous texture make it an excellent 

reservoir, and hence in spite of its great depth its oil-bearing possibilities should be tested in the structurally favorable localities hi the Lost 

Soldier-Ferris district. This sandstone lies within reach of the drill 

in the Lost Soldier, Mahoney, and Ferris domes, where it should be 

found at depths of about 4,050, 4,535, and 4,100 feet, respectively, as 

indicated in Table 3 (p. 29). Estimates of its depth in the Sherrard 

dome and Separation Flats anticline must await further testing of 

these folds to determine the location of their crests.

PERMIAN AND TRIASSIC RED BEDS.

The conspicuous red rocks of the Lost Soldier field are commonly 

considered to be equivalent to the Chugwater formation of central 

and northern Wyoming. The upper 1,375 to 1,400 feet consists of 

interbedded thin-bedded argillaceous sandstone and clay shale with 

intergradations of sandy shale and shaly sandstone. The deep-red 

color, which is an outstanding feature in this district, and the interbedding of sandstone and shale are shown through this entire thickness except in a gray, thinly and ripply laminated limestone, 5 to 7 feet 

thick, near the middle of the formation, a 2-foot bed of light-gray 

rather pure quartzose sandstone about 150 feet below the limestone,, 

and interbedded gray layers in the upper part that appear to indicate 

transitional phases into the overlying Sundance formation. Apparently there is an unconformity between the Sundance and the red 

beds, but in this locality it is not very marked.

The apparent complete absence of carbonaceous material hi this 

upper 1,400 feet of the red beds commonly correlated with the Chugwater has generally been considered adverse to the possibility that 

these beds may contain oil, but beds hi the Lander region, in the 

Hamilton dome near Thermopolis, near Maverick Springs, on the 

Red Spring anticline, and along the east flank of Rattlesnake Mountain, which have been correlated with the Chugwater, have either 

yielded oil in commercial amounts or given evidence of its presence 

by seepages. There can therefore be no doubt that the Chugwater,
STKATIGBAPHY. 15

or beds of the same general character, can at least act as an oil reservoir, 

and whether they contain oil in the Lost Soldier-Ferris district can 

be determined by the drill. On the crest of the Lost Soldier and 

Ferris domes the top of the red beds should be reached at depths of 

about 2,250 to 2,300 feet, on the Mahoney dome at abut 2,750 feet, 

and°on the Wertz dome at 4,300 feet. Estimates of the depth to 

the red beds on the Sherrard and Separation Flats folds are not 

made, for the reasons given in connection with the deeper formations.

The basal red beds in the Lost Soldier-Ferris district are by many 

considered to belong to the Embar formation, largely because they 

include numerous beds of limestone. There is no marked stratigraphic break between the basal limy beds and the overlying more 

sandy beds.

Below the uppermost cherty limestone in the red beds there is 

from 205 feet (Bell Springs) to 403 feet (Whisky Gap) of limestone 

interbedded with sandstone and red shale. A section measured at 

Whisky Gap furnishes a good idea of the character and relations of 

these beds, which rest conformably on the underlying Tensleep 

sandstone.

Section of limestone-bearing portion of red beds exposed in sec. 2, T. 27 N., R. 89 W.,

near Whisky Gap.

Limestone, impure, cherty, light gray; probably nonfossil- Feet. 

if erous.____-___-_______-__-_________-__--_..______-_ 45

Limestone, light gray, impure, interbedded with about equal

proportions of red sandy shale in beds about 5 feet thick. 40 

Rocks poorly exposed but apparently consisting of interbedded red shaly soft sandstone and red shale._________ 175

Limestone, impure, light gray _ _________________________ 3

Covered, probably red sandy beds_______--_---___--____ 60±

Rocks poorly exposed, consisting probably of interbedded

red sandy shale and light-gray impure limestone. __.__._ "0 

Tensleep sandstone.

The Embar is the oil-producing formation in sever. J fields in 

Wyoming, as shown in Table 2. In most of these fields the oil is 

contained in sandstone, but the fact that no sandstone or indications 

of oil were observed on the outcrops of the basal red beds .11 the Lost 

Soldier-Ferris district is no evidence that they would be found barren 

if penetrated by wells in favorable localities. If they contain oil or 

gas in this district, it would seem reasonable to expect that the 

cherty limestone would be the reservoir rock. As indicated in Table 

3 (p. 29), these beds probably lie within reach of the drill in the 

Lost Soldier, Mahoney, and Ferris domes, where they should be 

found, respectively, at depths of about 3,650, 4,135, and 3,700 feet. 

They probably lie within reach of the drill also on the Sherrard and 

Separation Flats folds, but in view of the lack of information concerning the crests of these folds accurate estimates of their depth 

there can not be made.
16 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

JURASSIC AND CRETACEOUS (P) ROCKS. 

SUNDANCE AND MORRISON FORMATIONS.

The rocks lying above the red beds and below the conglomerate 

of the Cloverly belong in the lower part to the Sundance formation 

and in the upper part to beds that vary greatly in both color, and 

lithology and are believed to be of Morrison age. The dividing line 

between the two formations in the Lost Soldier-Ferris district is not 

clear, and hence in this report they will be treated together. The 

formations as exposed about 1£ miles west of Whisky Gap are as 

follows:

Section of Morrison and Sundance formations in sees. 2 and 11, T. 27 N.,R. 89 W.

Conglomerate of the Cloverly formation. Feet. 

Morrison and Sundance formations:

Rocks poorly exposed, but consist principally of red shale 100

Rocks covered, probably mostly shale.________________ 100 .

Sandstone, light gray to brownish; upper part thin bedded 20+

Rocks poorly exposed, but probably consist principally of 

shale_____--_.___--________________________ 180

Limestone, sandy, and limy sandstone, not completely 

exposed; weather yellowish brown; thin bedded, ripple 

marked, and abundantly fossiliferous. The fossils consist principally of Camptonectes sp___________________ 8

Rocks poorly exposed, but probably consist almost altogether of shale__________________________________ 222

Sandstone, thin to thick bedded, yellowish gray, fairly 

fine grained_____________________________________ 60

Triassic red beds.

The limestone bed contains many remains of Camptonectes, which 

are characteristic of the Sundance; hence the limestone and lower 

beds in the above section belong to the Sundance formation. The 

base of the Sundance is here placed at the bottom of a series of beds 

which are distinctly not red and whose lower part generally though 

not invariably consists of a thick and more or less massively bedded 

sandstone. The beds above the limestone vary greatly from place 

to place in thickness, color, and lithology. The changes in color 

and lithology may take place within short distances for instance, 

thin-bedded yellowish sandstone changes through red shale to gray 

shale within less than a mile. In sees. 32 and 33, T. 28 N., E,. 89 W., 

beyond the area shown on Plate I, the beds above the limestone 

include a very massively bedded, highly porous light-yellowish 

sandstone more than 100 feet thick. Variations in the beds below 

the limestone also occur but are not so marked as those in the upper 

beds. As a result of these changes the Sundance and Morrison 

formations of this district can be described, in general terms, merely 

as a mass of varying shale and sandstone 400 to 700 feet thick lying
STEATIGEAPHY. 17

between the Triassic red beds and the conglomerate of the Cloverly 

formation and containing near the middle a thin persistent fossiliferous gray limestone.

The great variation in material, especially in the beds above the 

limestone, which are followed by the uniformly developed and persistent basal conglomerate bed of the Cloverly, indicates a decided 

unconformity between the Cloverly and the underlying formations. 

A remarkable feature of this unconformity is its parallelism to the 

general bedding in the Sundance and Morrison, which persists, 

throughout an extensive area in the Rocky Mountain region.

The sandstones of the Sundance and Morrison formations should 

furnish good reservoirs for oil and gas. Prior to 1921, however, 

only small seepages of oil have been obtained from the Sundance, 

and commercial quantities of oil are known to have been obtained 

from the Morrison at only one locality, the Grass Creek field. 10

In the Lost Soldier-Ferris district the Sundance and Morrison 

formations have been partly tested by the discovery well on the 

Mahoney dome, which penetrated these beds to a horizon 60 feet 

below the limestone. No showings of either oil or gas are noted in 

the well log. 'It is possible that the Producers & Refiners Corporation's well No. 2, in sec. 36, T. 26 N., R. 87 W., drilled to a depth of 

2,815 feet, or 1,635 feet below the contact between the Niobrara and 

Frontier, reached the upper part of the Morrison, but it is impossible 

to correlate the lower part of this log with the exposed stratigraphic 

section. Even if this well reached the upper part of the Morrison, its 

position on the flanks of the Ferris dome is not a favorable locality to 

test the oil or gas bearing possibilities of these beds.

As the upper part of the Morrison and Sundance formations has 

been tested in one favorable place with discouraging results, there is 

little incentive to drill wells to test only these beds in other structurally favorable places. The beds will nevertheless be tested by 

wells that will eventually be drilled to the deeper formations.

CRETACEOUS ROCKS.

' CLOVERLY FORMATION.

Along the south side of the Ferris Mountains the Morrison is overlain by a persistent conglomerate 25 to 30 feet thick, followed by a 

shale 125 to 150 feet thick, and this in turn by a slightly quartzitic 

sandstone 28 to 35 + feet thick. Hares u considers the conglomerate 

and shale to be of Lower Cretaceous age and the sandstone to be the 

Dakota. It is believed by the writers that these same beds consti10 Hevvett, D. F., personal communication. Heald, K. C., The oil-bearing horizons of Wyoming: Am. 

Assoc. Petroleum Geologists Bull., vol. 5, No. 2, p. 195,1921.

11 Hares, C. J., Anticlines in central Wyoming: U. S. Geol. Survey Bull. 641, pp. 244-245,1916.
18 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WTO.

tute the Cleverly formation in the Hanna Basin, a few miles to the 

east, as described by Bowen.12

There is considerable confusion in the Wyoming literature concerning this part of the stratigraphic section in the different regions, 

and the present investigation adds nothing to its clarification, except 

the above statement, which indicates the probable equivalency of 

the Dakota and Lower Cretaceous of central Wyoming and the 

Cloverly formation of the Hanna Basin.

During the summer of 1921 Willis T. Lee, of the United States 

Geological Survey, made stratigraphic studies in southeastern 

Wyoming, and one of the results of his studies is the correlation of 

the Muddy sand of east-central Wyoming with the upper sandstone 

of the Cloverly of this report, and because of this correlation the 

upper sandstone of the Cloverly will here be spoken of as the Muddy 

sand. It is thought that the Muddy sand of this area occupies 

approximately the same stratigraphic position as the Muddy sand of 

the Big Horn Basin, and if it does, some of the underlying shale 

included in the Cloverly by Bowen would correspond with the lower 

part of the Thermopolis shale of the Big Horn Basin.

At some places on the south side of the Ferris Mountains the 

pebbles in the conglomerate are so small that the bed can be classed 

as a quartzitic sandstone. In the Bell Springs area, to the south, 

the conglomerate grades upward into quartzitic sandstone at the 

top, and at one place was found to be 75 feet thick. At another 

place in this vicinity Lee found the conglomerate to be 61 feet thick 

and to be overlain by 10 feet or more of shale in a poorly exposed 

interval, which in turn was followed by quartzose sandstone about 

15 feet thick. In this same locality the shale that overlies the 

quartzose sandstone and separates it from the Muddy sand is 135 

feet thick.

The upper sandstone (Muddy sand) of the Cloverly is present in 

the Bell Springs area only as a shaly sandstone and measures 20 to

25 feet in thickness. In some places it may be represented only 

by a sandy zone in the shale, and in such places the top of the 

Cloverly might be difficult to discern.

The Cloverly is of particular interest because of the oil and gas 

content of the Muddy sand, which is the reservoir rock in the Lost 

Soldier dome at a depth of 1,375 feet. The Muddy is also the gasbearing member in the Mahoney dome, at a depth of 2,160 feet in 

the discovery well in the southwest corner of the NE. £ sec. 34, T.

26 N., R. 88 W. The gas wells on the Ferris dome obtain their 

supply from the Cloverly formation, and the well logs indicate that

» Bowen, C. F., Stratigraphy of the Hanna Basin, Wyo.: TJ. S. Geol. Survey Prof. Paper 108, pp. 227- 

241,1918.
STRATIGRAPHY. 19

the sand is the Muddy. In well No. 4, in sec. 25, T. 26 N., R. 87 W., 

it is found at a depth of 1,795 feet. The gas sand in the Wertz 

dome, reached at a depth of 3,400 feet in the discovery well, is also 

the Muddy. If the writers have correctly interpreted the field 

evidence and the logs of wells on the Sherrard dome the Cloverly 

should be found at depths of 3,100 feet or less in the vicinity of the 

wells in sees. 2 and 11, T. 25 N., R. 89 W. It should lie at shallower 

depths at plaees structurally higher on the dome.

THERMOPOLIS SHALE.

The interval between the Cloverly formation and the Mowry shale 

which measures between 50 and 135 feet, consists in general of 

finely laminated dark-gray soft shale, which is considered to represent 

the Thermopolis shale as described by Bowen in his report on the 

Hanna Basin.13 As pointed out in the discussion of the Cleverly, 

however, it seems likely that the Thermopolis shale as here described includes only the equivalent of the upper part of the Thermopolis of the type locality in the Big Horn Basin,14 the lower part 

being here included in the Cloverly.

Owing to its softness the Thermopolis is very poorly exposed. 

Where the upper sandstone of the Cloverly (Muddy sand) is hard 

and resistant, the boundary line between the Cloverly and the 

Thermopolis is readily determined, but where this sandstone is 

shaly or absent the line separating the Thermopolis from the Cloverly 

is indistinct. Except for this variation in the Muddy sand, a feature 

which may be purely depositional, the Thermopolis appears to lie 

conformably with the formations both below and above.

In sec. 11, T. 27 N., R. 89 W., north of the area mapped on Plate 

I and southwest of Whisky Gap, the Thermopolis shale is about 115 

feet thick and near its base contains some coaly or very carbonaceous 

material. In the vicinity of Bell Springs, where the upper sandstone 

of the Cloverly is shaly, the Thermopolis and Mowry together occupy 

an interval of only 135 feet and were not separately measured.

Although the Thermopolis shale has been penetrated by wells 

in five of the domes in the Lost Soldier-Ferris district, no indications 

of oil or gas have been reported from it. So far as observed at the 

surface it contains no distinct sandy zones, and therefore it should 

probably not be classed among the oil or gas bearing beds, although 

its content of carbonaceous or coaly material, mentioned above, 

would seem to indicate that it carries material from which oil and gas 

could possibly be derived.

On the west side of Big Horn River 15 and in other parts of Wyoming the Thermopolis is reported to contain an oil or gas bearing

« Bowen, C. F., Stratigraphy of the Hanna Basin, Wyo.: U. S. Geol. Survey Prof. Paper 108, p. 229,1918.

" Lupton, C. T., Oil and gas near Basin, Big Horn County, Wyo.: U. S. Geol. Survey Bull. 641, p. 168, 

1916.

15 Hewett, D. F., and Lupton, C. T., Anticlines in the southern part of the Big Horn Basin, Wyo-: U. S. 

Geol. Survey Bull. 656, pp. 19-20,1917.
20 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

sand which is known as the Muddy sand among the oil operators of 

that region. In central Wyoming the term Muddy is applied by 

drillers to the upper sandstone member of the Cloverly, which in 

some of the geologic literature is called the Dakota sandstone. This 

double use of the term is confusing, but the writers believe that 

there is some reason for thinking that the drillers' Muddy sand is 

one and the same in all these localities, and that the geologists' 

classification in the different regions needs revising. *

The present writers have no information to help clarify this situation, and further detailed stratigraphic work in the area between the 

Big Horn Basin and central Wyoming is needed.

MO WRY SHALE.

In this district, as in many other localities in the Rocky Mountain 

States, the Mowry shale is dark gray, but weathers whitish and is 

readily distinguished by its content of fish remains, principally scales, 

and by its fissile character and greater hardness than most other 

shales. Along the south flank of the Ferris Mountains it is 200 feet 

thick, but to the south, in the Bell Springs area, the Mowry and the 

underlying Thermopolis together measure only 135 feet.

The Mowry shale is well exposed southwest of Whisky Gap, where 

the entire formation consists of fairly pure shale. There is no indication here that the Mowry contains porous beds which.could serve 

as reservoir rocks, yet in the Lost Soldier and Ferris fields oil is obtained from it. The wells that obtain oil from the Mowry do not 

penetrate this formation to a common horizon, but instead appear 

to obtain their oil at different horizons. The absence of sandstones 

in the Mowry at its outcrop seems to call for some explanation to 

account for the presence of oil in it underground. To the writers a 

possible explanation seems to lie in the rather hard and brittle character of the shale, which permits the presence of small open crevices, 

either joints or minor faults. Observations of other shales in the 

Lost Soldier field seem to indicate that only the Mowry has the 

ability to sustain openings of any appreciable size after they are 

once formed, and the minor faults in the Lost Soldier and Mahoney 

domes suggest that all the harder formations, where folded, have 

been subjected to fissuring and minor faulting on an extensive scale. 

Similar conditions appear to exist in the Wertz dome, where the discovery well encountered oil in the Mowry shale at depths of 3,140 to 

3,175 feet under so great a pressure that a small production is being 

obtained from between the casings of the well, which is primarily 

a gas well obtaining gas from the Muddy sand, at the top of the 

Cloverly, at a depth of 3,400 feet.
STBATIGRAPHY. 21

The following fossil forms, identified by T. W. Stanton, were obtained from the Mo wry:

Leucichthyops vagans Cockerell. 

Erythrinolepis mowriensis Cockerell. 

Holcolepis sp. 

Fish bones.

FRONTIER FORMATION.

The prominent characteristic feature of the Frontier formation^ 

is the presence in its upper part of two to four resistant sandstones,, 

which in places where the formation lies in a highly inclined position 

form prominent dip slopes, walls, or cliffs. The interval between, 

these sandstones and the underlying Mowry is occupied by soft shalewhich in this report is considered as belonging to the Frontier formation. The sandstones of the Frontier are probably the richest 

oil-bearing rocks in Wyoming,

Section of Frontier formation as exposed in sec. 32, T. 27 N., R. 88 W.

Carlile shale.

Frontier formation: FeetSandstone, medium to fine grained, cross-bedded and 

mostly thin bedded; fossiliferous. This sandstone 

forms a very prominent and strikingly picturesque 

sloping wall (see Pis. Ill, B: IV, B) on the mountainward side of the soft Carlile, Niobrara, and Steele 

shale belt. Known as the Wall Creek sand-_____ 30J.

JShale, gray. At 5 to 8 feet from the top is a hard limy 

layer about 1 foot thick which seems to be in part of 

concretionary origin. From this layer and from the 

base of the still higher sandstone ledge were collected 

Ostrea sannionis White, Inoceramus erectus Meek, 

Cardium pauper-culum Meek, Lunaiia sp., Nautilus 

sp., Baculites gracilis Shumard?, Exogyra sp., Volutoderma sp., and Scaphites ventricosus Meek and 

Hayden___.______-___.-__. -----_. 70'

Sandstone, medium to fine grained, cross-bedded and 

mostly thin bedded. No fossils were found. Ledge 

forming.__-_____-___--_________--_-_-__--______ 1&

Shale, poorly exposed____________________________ 15'

Sandstone, medium to fine grained, cross-bedded and 

mostly thin bedded. No fossils were found. Ledge 

forming----_-_--__-_--_------.-----------___-__ 23

Shale, poorly exposed_________-___________________. 63-

Sandstone, medium to fine grained, thin bedded except 

for upper 10 to 15 feet, which is fairly massive. The 

lower part grades into the underlying shale. Ledge 

forming-.______--___-_-__---_----_--_----_____- 120

Shale, poorly exposed________-__________-'-----_--__ 355

Sandstone, thin bedded, upper 9 feet light gray, lower 

5 feet highly ferruginous and dull brown. Ledge 

forming. Appears to be of local development only. _ 14 

Shale to top of Mowry shale, interval unmeasured;

probably about 300 feet. 

Mowry shale.
22 OIL, AND GAS, LOST SOLDIER-FERKIS DISTRICT, WYO.

The prominent sandstones at the top of this section, of which the 

uppermost is the Wall Creek sand of the drillers, decrease in number 

westward, and in sec. 3, T. 27 N., R. 89 W., where Muddy Creek cuts 

through them in turning north toward Sweetwater River (outside of 

the area mapped on PL I) only two sandstone beds are present. 

Similarly, in the southern part of the district east of Bell Springs 

three sandstone beds are present. From this it is obvious that the 

number of Frontier sands differs in the different fields. These 

Frontier sandstone beds are the shallow pay sands of the Lost Soldier 

dome, found at a depth of 239 to 584 feet on the apex of the dome. 

In the log of well No. 22 of this field (see PL VIII) three distinct sands, 

of which the upper one is the Wall Creek, are shown to be present in 

the Frontier formation. Still another sand in the lower part of the 

formation is also recorded, and this may represent the sand about 

300 feet above the Mowry in the section just given.

The Wall Creek and other sands at the top of the Frontier were 

found at depths of 2,145 to 2,530 feet in the discovery well in the 

Wertz "dome," in the northeast corner of the SW. i sec. 7, T. 26 N., 

R. 89 W., and at depths of 890 to 1,215 feet in the discovery well in 

the Mahoney dome, in the southwest corner of the NE. £ sec. 34, 

T. 26 N., R. 88 W. In the Ferris dome these sands are found at 

depths of 290 to 510 feet in well No. 2, which is probably a short distance away from the highest point of the dome, and in the Sherrard 

dome the Wall Creek sand was encountered at a depth of about 1,850 

feet in a well in the southwest corner of the SE. % sec. 2, T. 25 N., 

R. 89 W. It seems probable that the Frontier sands have been 

penetrated in the Separation Flats anticline at depths of 975 to 

1,350 feet in the New York Oil Co.'s weU, in the SE. i sec. 31, T. 24 

N., R. 88 W., and at depths of 2,180 to 2,570 feet in the Midwest 

Refining Co.'s well in sec. 16 of the same township. In the logs of 

these two wells that were accessible to the writers no indications 

of either oil or gas are recorded. In the well drilled in sec. 2, T. 24 

N., R. 26 W. in the O'Brien Springs anticline the Wall Creek sand 

was encountered at 3,120 feet and gave a good showing of gas. A 

deeper sand of the Frontier formation at a depth of 3,630 feet yielded 

gas1 amounting to several million cubic feet daily.

Although the Frontier sands have been penetrated in seven of the 

domes and anticlines in this district, they contain commercial quantities of oil in only one, the Lost Soldier dome. Gas with an estimated flow of 7,000,000 cubic feet a day was encountered in the 

discovery well in the Mahoney dome, at a depth of 1,130 to 1,140 

feet, which is 240 feet below the top of the Wall Creek sand. This 

gas was cased off for deeper drilling. The flows of gas in the test well 

on the O'Brien Springs fold were estimated at 1,000,000 to 3,000,000 

cubic feet a day. Showings of oil were encountered in the Wertz
STRATIGRAPHY. 23

and Sherrard domes, and of gas and oil in the Ferris dome. The oil 

in the Frontier sands in the Lost Soldier dome, according to E. W. 

Krampert, 16 is due to leakage along fault planes from the underlying 

Muddy sand. The reasons for this conclusion are given in the detailed description of the structure of that field (pp. 33-34).

CARLILE AND NIOBRARA SHALES. '

In the Hanna Basin 17 and in central Wyoming 18 the strata overlying the Frontier formation consist of a few hundred feet of Carlile 

shale followed by two to four times as much Niobrara shale. In the 

Lost Soldier-Ferris district no lithologic or paleontologic evidence 

was observed for differentiating these shales above the Frontier into 

the two formations, and hence, for the purpose of this report they 

are considered together.

The Carlile and Niobrara unit in the Lost Soldier-Ferris district 

consists almost wholly of soft dark-gray, thinly laminated shale, 

with a few thin white streaks of bentonite. Its differentiation from 

the Frontier formation below is marked by the upper surface of 

Frontier sandstone. Its upper limit is not so readily determined. 

The Steele shale, more than 4,000 feet thick, overlies the Niobrara, 

and the only horizon marker near the contact of these two formations 

consists of three to five 1-foot beds of yellowish-brown laminated 

limy argillaceous sandstone, which are distributed through an 

interval of 150 to 250 feet. Associated with these thin yellowishbrown beds, but more particularly above them, there is some thinbedded soft argillaceous 'sandstone. The beds that overlie the 

yellowish beds occupy an interval of probably not more than 40 feet. 

The yellowish and associated sandstones should probably be considered transition beds between the Niobrara and Steele. The 

thin yellowish-brown layers are the distinctive features of these 

transition beds, and the uppermost of these, which is more generally 

exposed, is regarded in this report as marking the upper boundary 

of the Niobrara shale. No Montana fossils were found below this 

horizon, and no Niobrara forms were found above it; hence for 

practical purposes this horizon does very well as a formational 

boundary. The Carlile and Niobrara unit, including the series of 

thin yellowish-brown sandy layers which mark its top, is well exposed in sees. 4 and 5, T. 26 N., K. 88 W., where it has a total thickness of 1,425 feet. The thin yellowish-brown beds are well shown 

in the first rock exposures north of the creek at the north side of 

the Lost Soldier field and in the hill about half a mile southeast of

18 Personal communication.

» Bowen, C. F., Stratigraphy of the Hanna Basin, Wyo.: U. S. Geol. Survey Prof. Paper 108, pp. 227 

241,1917. 

w Hares, C. J., Anticlines in central Wyoming: U. S. Geol. Survey Bull. 641, pp. 233-279,1916.
24 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

this field. They are also exposed in sees. 2, 3, 4, and 5, T. 25 N., 

R. 88 W., at the southeast, south, and southwest sides of the Mahoney 

field, also in the Ferris field and at a few other localities, as indicated 

on Plate I.

The fauna of the Niobrara consists principally of Uintacrinus 

socialis Grinnell, which is diagnostic, and Ostrea congesta Conrad, 

which is characteristic in the Rocky Mountain region. In addition 

to these two forms there are present many fragments of a thickshelled Inoceramus, upon which the Ostrea congesta colonized, and 

forms identified by T. W. Stanton as Baculites asper Morton and 

scales of Hypsodon and other fishes. No distinctive Carlile species 

were found in the lower part of the shale.

The sandstone at the upper boundary of the Niobrara may be the 

reservoir rock in the G. P. dome, found at a depth of 3,020 feet in 

the discovery well.

STEELE SHALE.

The Steele shale crops out in most of the district within the encircling ring of the Mesaverde formation, but it is in most places concealed either by recent alluvium or dune sand. For study it is best 

exposed on the north side of the Camp Creek syncline. The base 

of the Steele shale is not clearly defined, but as noted above under 

the Carlile and Niobrara shales, for the purpose of this report it is 

considered to be at the top of the uppermost of a series of thinly 

laminated beds of limy, argillaceous sandstone, each about 1 foot 

thick, which weather yellowish brown. A Montana species, Inoceramus bambini Morton, was found within 20 feet above this sandstone, 

and it is possible that the Steele shale should be considered as extending below this sandstone series, but the facts that this peculiar series 

of yellowish-brown sandstone beds is the only key horizon that can 

be generally recognized as lying near the contact between the Niobrara and the Steele shales and that no Montana fossils were found 

below it seems sufficient reason for considering it to mark an approximate boundary line between these two formations. The upper boundary of the Steele shale is considered to lie below the lowermost thick 

white sandstone of the Mesaverde. In some places there are lenticular sandstones lying below this white sandstone, but they are 

regarded as transition beds and are included here in the Steele.

The Steele is essentially a soft gray shale formation, which usually 

forms depressions in the surface. Distributed here and there within 

the main body of the shale are zones of sandy shale and argillaceous 

sandstone, and the upper part of »the formation contains well-defined 

sandstone beds.

In the lower part of the formation are some beds of argillaceous 

sandstone, one of which, about 40 feet thick in the Lost Soldier field,
STKATIGRAPHY. 25

is at the base, immediately overlying the thin yellowish-brown beds 

of the Niobrara. This sandstone is of interest in connection with 

the oil of the G. P. "dome," which comes from a "sand" that the 

writers consider to be one of these argillaceous sandstones of the 

Steele or a sand hi the upper part of the underlying Niobrara. The 

uncertainty in the correlation of the G. P. sand is discussed in the 

description of the G. P. "dome."

A persistent sandstone zone, possibly a continuous sandstone bed, 

which measures 30 to 60 feet in thickness on the outcrop, is present 

about 1,400 to 1,500 feet below the top of the formation. It is well 

exposed across the north sides of sees. 15 and 16, T. 26 N., R. 89 W., 

and is present in intermittent exposures to the west and south of 

the Table Hills and along the west and north sides of the Haystack 

Hills.

Above this persistent sandstone zone other sandstones are present, 

but these are generally thin and represent principally transition beds 

into the overlying Mesaverde formation.

The Steele shale varies somewhat in thickness in this district, 

thinning noticeably toward the northwest. In sees. 5 and 6, T. 26 

N., R. 88 W., a detailed measurement gave it a thickness of 4,745 

feet. There is some reason for thinking that this is a normal thickness for the eastern and southern parts of the region. The thinning 

toward the northwest appears to take place principally in that part 

of the formation lying above the persistent thick sandstone bed, 

and it is possible that on the west side of the Lost Soldier dome the 

thickness may be less than 4,000 feet. This thinning toward the 

northwest corresponds with a similar but much greater thinning in 

the overlying Mesaverde formation, described below.

Numerous fossil collections were made from the Steele shale, some 

of which have considerable stratigraphic interest.

Lot 165, in the Table Hills south of the G. P. field, about 300 feet below the 

top of the formation:

Ostrea sp.

Pteria nebrascana (Evans and Shumard).

Inoceramus barabini Morton.

Baculites anceps var. obtusus Meek. 

Lot 139, 3,930 feet above the base, in the SW. 1 sec. 1, T. 26 N., R. 89 W.

Pteria nebrascana (Evans and Shumard).

Cryptodon? n. sp.

Lunatia sp.

Aporrhais? sp.

Scaphites n. sp.

Scaphites? sp.

Baculites ovatus Say. 

Lot 136, 2,087 feet above the base, in sec. 6, T. 26 N., R. 88 W..

Nautilus sp.

Helicoceras? sp.

Scaphites hippocrepis Dekay.
26 OIL AND GAS, LOST SOLDIEB-FEKBIS DISTRICT, WYO.

Lot 134, from NW. J sec. 12, T. 26 N., R. 90 W. (same horizon as lot 136):

Ostrea sp.

Inoceramus barabini Morton.

Lucina sp. cf. L. subundata Hall and Meek.

Gyrodes? sp.

Baculites ovatus Say.

Helioceras? sp.

Scaphites hippocrepis Dekay.

Fish scale. 

Lot 137, 1,537 feet above the base, in sec. 6, T. 26 N., R. 88 W.:

Pteria linguaeformis (Evans and Shumard)?

Baculites ovatus Say. 

Lot 146, 1,100 feet above the base, in sec. 5, T. 26 N., R. 88 W.:

Portheus sp., a vertebra.

Lamna cf. L. appendiculata, a tooth.

Scapanorhyncus sp., two teeth.

Plesiosauridae, genus and species unrecognizable, a vertebra.

The most interesting feature in fossil lots 134 and 136, according 

to T. W. Stanton, who identified them, is the presence of Scaphites 

hippocrepis Dekay, which in eastern and northeastern Wyoming is 

distinctive for the Eagle sandstone, in the basal part of the Montana 

group. This form was found in the Lost Soldier-Ferris district at two 

widely separated places, but apparently they represent one and the 

same horizon, which, as given, is 2,087 feet above the base of the formation. In this locality no sandstone is associated with the beds at 

this horizon other than a thin and slightly sandy zone in the shale.

MESAVERDE FORMATION.

The Mesaverde, a brackish and shallow water formation, and the 

marine Steele and Lewis shales form the Montana group of the Cretaceous system in this district. In some parts of the Rocky Mountain 

region the Montana group is composed entirely of marine shale, but 

where the Mesaverde is present this formation ,is interpreted as 

consisting of the more localized shallow and brackish water sediments 

of late Montana time which were deposited near the land. The 

Mesaverde is differentiated from the underlying and overlying marine 

shale sediments principally on lithologic grounds and the presence 

of a brackish water rather than a purely marine fauna. It is coal 

bearing also. The sandy brackish-water deposits are considered 

contemporaneous with marine deposits elsewhere, and through the 

variation hi extent of its different sandstone beds the Mesaverde in 

places interfingers or lies more or less interbedded with marine 

deposits.

The Mesaverde in this district is normally characterized by three 

divisions a sandstone division at the base, another at the top, and 

a shale division in the middle. The sandstone divisions consist of 

thick beds of sandstone interbedded with alternating thin beds of 

shale and thin sandstone. The shale division consists of interbedded
TJ. S. GEOLOGICAL SURVEY BULLETIN "56 PLATE V

 *«.

A. MESAVERDE ESCARPMENT ON£3OUTH SIDE OF LOST SOLDIER DOME.

li. MKSAVEKDK ESCARPMENT IN NORTHEASTERN PART OF T. 24 N., K. 89 W.

C'. TABLE HILLS FROM THE NORTHWEST. 

The uppermost ledge is the base of the Mesaverde formation.
17. 8. GEOLOGICAL SURVEY 

A. ADJACiiM' J'OlfTKI.NS OK A COMl'LETK SECTION OF THE MESAVKIID

The arrows point lo a li'd^c, which is the same in both photographs. The mi

R. VIEW ACROSS THE G. P. OIL FIELD LO
STKATIGKAPHY. 27

thin dark-gray to brown shale, sandy shale, and light-gray to yellowish and reddish-brown sandstone with a few layers of brown limy 

sandstone. This middle shale division where exposed presents a 

striking banded appearance, which is well shown in the range of 

hills crossing Tps. 23 and 24 N., R. 89 W. So far as observed in this 

district, the middle division contains no coal, but thin beds of coal 

occur in both sandstone divisions.

In view of the conclusion that the Mesaverde is composed of 

the sandy and brackish-water deposits lying above the marine Steele 

shale as mentioned above and that its lower sandstone beds are 

interbedded with the uppermost portions of this shale, no definite 

line of demarkation between the two formations can be drawn. 

For the general purposes of this report, however, the lowest thick 

white sandstone in the Lost Soldier-Ferris district will be considered 

the basal bed of the Mesaverde (see PI. V, 0), though still lower

lenticular sandstones are present in some localities.

In a somewhat similar way the upper boundary is also difficult 

to define. For general purposes the uppermost thick white sandstone (Teapot member) can usually be considered the top of the 

formation, but in sees. 17 and 18, T. 25 N., R. 89 W., where higher 

beds are exposed, it was found that coaly material and thin sandy 

beds continue for 410 feet above the Teapot sandstone member, 

and that at the top of this series are two oyster beds, which are 

indicative of brackish-water instead of marine conditions, as should 

be postulated for the overlying Lewis shale. Whether similar coaly 

and brackish-water material is present above the uppermost thick 

white sandstone in other parts of the district was not determined 

during this investigation.

The Mesaverde formation is very well exposed in the escarpments 

and hogback ridges that border the Lost Soldier-Ferris district on 

all sides except south and northeast. (See PL V, A, B.) In these 

exposures the thickness of the formation varies greatly. Where 

it appears to be most normally developed that is, in the Haystack 

and Table hills and in Tps. 23 and 24 N., R. 89 W. it measures 

1,700 to 1,900 feet, but northward from T. 25 N., R. 89 W., to the 

southwest side of the Lost Soldier dome it thins rapidly, and in sec. 

22, T. 26 N., R. 90 W., it probably measures less than 200 feet. 

This thinning appears to take place principally by the complete 

elimination of the middle thick shale and a general thinning of the 

other divisions. This thinning could be explained by assuming a 

local deformation centering somewhere to the west which shallowed 

the sea or perhaps even caused a slight elevation above the water 

level during Mesaverde time.

On the north side of the Lost Soldier dome and in the Camp Creek 

syncline the formation thickens again, but at no place in the northern 

part of the district is it known to reach its normal thickness or to 

exhibit its normal threefold lithologic division. Where the road
'28 OIL AISTD GAS, LOST SOLDIER -FEERIS DISTRICT, WYO.

to Whisky Gap crosses the west flank of the Camp Creek syncline,

 the Mesaverde is well exposed (see PI. V, A), but its middle shale

 division is lacking and its thickness is but 785 feet.

The following fossils were obtained from the Mesaverde formation:

Lot 129, in the NW. i sec. 17, T. 25 N., R. 89 W., 410 feet above the uppermost thick white sandstone, near the top of the Mesaverde formation:

Ostrea glabra Meek and Hayden. 

Lot 157, 10 feet above the base of the formation, in sec. 23, T. 25 N., R. 87 W.:

Ostrea sp.

Pteria nebrascana (Evans and Shumard).

Lunatia sp.

Fusus (Lerrifusus?) sp.

Baculites anceps var. obtusus Meek.

Baculites ovatus Say.

Lot 167, in the Table Hills south of the G. P. field, about 370 feet above the 

base of the formation:

Ostrea glabra Meek and Hayden.

Corbula subtrigonalis Meek and Hayden.

The uppermost thick white sandstone of the Mesaverde, the 

Teapot sandstone member, is oil bearing on the east flank of the 

Rattlesnake Mountains,19 but no evidence of oil in this sandstone was 

observed in the Lost Soldier-Ferris district. Even if it were oilbearing it is not buried in any of the domes or anticlines in this 

district and therefore could not serve as an oil reservoir.

LEWIS SHALE.

The Lewis shale is a soft nonresistant formation which as a general 

rule is poorly exposed and usually forms depressions in the surface. 

The best exposure of the Lewis in this district is in the Camp Creek 

.syncline east of the road leading to Whisky Gap, where it consists 

of dark-gray, thinly laminated shale together with several beds of 

soft yellowish-brown sandstone, the thickest of which measure about 

20 feet. The following fossils, identified by T. W. Stanton, were 

obtained from the Lewis:

Lot 143. Near the base of the shale, in the NW. | sec. 3, T. 26 N., R. 89 W.:

Ostrea sp.

Glycimeris wyomingensis (Meek).

Lucina sp.

Cardium speciosum Meek and Hayden.

Lot 155. About 700 feet northeast of the bench mark in sec. 15, T. 24 N., R. 

$0 W.:

Ostrea glabra Meek and Hayden.

Gryphaea? sp. May be abnormal specimens of preceding species but 

simulate Comanche forms of Gryphaea.

Glycimeris wyomingensis Meek.

DISTRIBUTION OF OIL AND GAS.

The stratigraphic distribution of oil and gas in the folds of the 

district is set forth in Table 3, which is based on developments up to 

November 1, 1920.

i<>Hares, C. J., Anticlines in central Wyoming: U. S. Geol. Survey Bull. 641, pp. 246-247,1917.
TABLE 3. Stratigraphic distribution of oil and gas and approximate minimum depth 0 

Soldier-Ferris district.

[Figures in parentheses indicate depth in feet.J

£ Formation. 

» 

Mesaverde formation .

Niobrara and Carlile 

shale.

Frontier formation....

Thermopolis shale. . . . 

Cleverly formation. . . -

Morrison and Sundance formations. 

Triassic and Permian red beds.

Tensleep sandstone. . .

Amsden formation. . . . 

Madison limestone. . . -

Cambrian quart zite. . . 

Pre-Cambrian granite.

Lost Soldier 

dome.

Oil (240).......

Showing of oil 

(1,150).

Oil (1,375)......

Untested(l,750- 

2,250). 

Untested (2,250- 

3,650). 

Untested 

(3,650±). 

Untested 

(4,050±).

Untested 

(4,450±).

Untested 

(5,000±).

Wertz "dome."

Surface.........

Barren (2,145)..

Showing of oil 

(3,140).

Gas (3,410).....

Untested (3,800- 

4,300). 

Untested (4,300- 

5,675) 

Untested 

(5,675±). 

Untested 

(6,075±).

Untested 

(6,475±).

Untested 

(7,000±).

Bunker Hill 

dome.

Only upper 300 

feet tested.

Untested 

(6,700±).

.....do..........

.....do..........

.....do.......... 

.....do.......... 

.....do.......... 

.....do.......... 

!... ..do... .......

I... ..do.... ......

.....do..........

Maboney dome.

Showings of oil 

and gas (860).

Showing of gas.

Gas (2,160).....

Barren (?) 

(2,250-2,750.) 

Untested (2,750- 

4,135). 

Untested 

(4,135±). 

Untested 

(4,535±).

Untested 

(4,950±).

Untested 

(5,500±).

Ferris dome.

Showings of oil 

and gas (235).

Oil with gas 

showings 

(1,200-1,300). 

Barren (?).. .. 

Gas (1,425).....

Untested(l,825- 

2,325). 

Untested (2,300- 

3,700). 

Untested 

(3,700±). 

Untested 

(4,100±). 

Untested. ...... 

Untested 

(4,500±). 

Untested....... 

Untested 

(5,000±).

G

O

U

..

..

..

..

..

..

..

..

..

..

o These estimates may vary by several hundred feet because of varying thickness in stratigraphic intervals.
30 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

STRUCTURE. 

REGIONAL FEATURES.

The Lost Soldier-Ferris district lies at the north end of the Rawlins 

uplift, one of the major upfolds of the Rocky Mountains in Wyoming. 

The Rawlins uplift is not large in area in comparison with other major 

upfolds, but the fact that it is elevated so high that pre-Cambrian 

crystalline rocks are exposed along its axis is sufficient reason to class 

it with them. Its alinement is northerly and it is therefore a part of 

that series of Rocky Mountain flexures which are characterized by 

northerly lines of folding and faulting. The Rawlins uplift is one of a 

group of major upfolds that form the northernmost of a northwardalined series, north of which the direction of the normal Rocky 

Mountain folds abruptly changes to east. The northerly trend is 

resumed in the Wind River Mountains. The Rawlins uplift measures 

about 50 miles in length and 20 miles in average width. It extends 

some distance beyond the boundary line marking the top of the Steele 

shale. From the general horizontal position of the Wasatch beds, of 

Tertiary age, on the west side of the uplift, it seems that the development of this uplift was complete or almost complete by the beginning of Wasatch time. The central core of the uplift is marked by 

an area of pre-Cambrian granite northwest of the town of Rawlins 

from which the sedimentary rocks dip at steep angles on the west 

and at more gentle angles on the east. The west flank of the anticline immediately adjacent to the central granite core is modified by 

a zone of faults, and farther north this fault zone turns northeastward 

and cuts across the axis of the fold. The portion of the uplift lying 

north of this fault is the down-dropped side, and it is this lower north 

end of the uplift which is occupied by the Lost Soldier-Ferris district.

The district contains several lines of minor folds, the upfolds of 

which are accentuated by local high portions or domes, which are thecontrolling features for the accumulation of the oil and gas found in 

this district. These domes and the accompanying oil accumulations 

are described in detail on later pages. The alinement of these folds 

in relation to the major upfolds of the region is shown on Plate L 

The noteworthy feature of the alinement of the folds is that in general 

they lie transverse to the major axis of the Rawlins uplift. This 

transverse arrangement would appear to indicate that the forces 

which formed them were not the same as those which caused the 

Rawlins uplift. The significance of the transverse position has been 

discussed at some length by the senior author.20 The argument followed in that paper is that (a) the folds' do not, as would ordinarily 

be expected, lie parallel to the longitudinal axis of the Rawlins uplift,

20 Fath, A. E., The age of the domes and anticlines in the Lost Soldier-Ferris district: Jour. Geology, vol. 30, No. 4, pp. 303-310,1922.
STRUCTURE. 31

but instead lie parallel with the Ferris-Seminoe line of deformation;. 

(&) this parallelism indicates that the folds and the mountains are 

probably due to the same forces; (c) the Ferris and Seminoe mountainsare considerably younger (at least post-Wasatch) than the Rawlins 

uplift (pre-Wasatch), and the minor rock folds are therefore also 

younger than this uplift.

The significance of this argument in relation to oil and gas is that 

any oil or gas which had been formed prior to the minor folding of 

the Lost Soldier-Ferris district and was located or had migrated a 

short distance beyond the catchment areas of the present fields must 

have migrated toward the crest of the uplift and there been lost 

through the eroded edges of the formations that contained it. The 

oil and gas of the present fields and possibly an additional quantity 

in fields not yet proved must represent that formed by the dynamochemical action of the later deformational forces which produced 

these minor flexures, and in addition that of earlier distillation which 

was already present within their catchment areas. This quantity, 

however, must represent but a fraction of that which was formed 

within the area embraced by the Rawlins uplift. The oil and gas 

that is present in this district to-day for the use of man must therefore be merely a remnant of all the oil derived from the mother material which the rocks of this region originally contained.

This hypothesis is not accepted by a number of geologists who 

have worked in the Wyoming fields, nor by geologists who do not 

believe that oil can migrate long- distances. K. C. Heald 21 believes 

that, even though oil may once have accumulated in the Rawlins 

uplift, most of it would probably have followed the retreating water 

table down the flanks of the uplift as erosion neared the oil-containing 

beds, and that therefore only the portion which would not drain by 

gravity from the containing rocks would be lost. He also maintains that as soon as surface water had begun to enter the oil sand 

the tendency of the water would be to push the oil basinward and 

force it into flexures on the flanks of the main uplift.

METHODS USED IN REPRESENTING STRUCTURE.

The top of the Wall Creek sand was considered to be the best horizon for showing the geologic structure of the Lost Soldier-Ferris district. The attitude of this surface was determined (1) by mapping, 

the location, determining the dip and strike, and obtaining the altitude of the exposed key beds, and by locating and obtaining the altitude of wells in the logs of which key beds have been recognized 

and recorded; (2) by determining the thickness of the strata between 

the several key beds in the stratigraphic section; (3) by computing,

21 Personal communication.
32 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

from the altitudes obtained, the altitude of the top of the Wall Creek 

sand; and (4) by drawing contours showing the configuration of the 

Wall Creek sand, by using not only the computed altitude of its top 

but also the dip and strike of the key beds. The result is represented by structure contours on Plate I.

Throughout a large part of the district the rocks are covered with 

alluvium and dune sand, and the contours drawn for these areas are 

wholly inferred, as there is no available information on which they 

can be based. To make such contours clearly distinct from those 

for which there is some evidence, they are shown in green.

Within the 6,000-foot interval of shale (Carlile, Niobrara, and 

Steele) that forms the outcropping rock in the great central area of 

the district, where not concealed by alluvium and dune sand, only 

one key horizon has been recognized that is common to two or more 

localities. This horizon, or rather zone, consists of the transition 

beds at the top of the Niobrara shale. The lack of definite structure 

contours in so much of the area occupied by these thick formations 

can therefore be readily understood.

EFFECTS OF STEEP DIPS.

The altitude of the Wall Creek sand can not be calculated from 

the altitudes determined for the key beds mapped at the surface by 

merely subtracting the thickness of the intervening strata, except 

where the beds lie horizontal. The dip of the beds must be taken 

into consideration, because the vertical distance through a dipping 

formation is greater than the stratigraphic thickness, the difference 

depending on the rate of dip. The vertical distance from the surface 

to the Wall Creek sand was obtained by the formula t = T sec a, in 

which £=vertical distance, T= stratigraphic interval, and a =angle

of dip. This formula is applicable to all similar problems, and results for certain angles are given in the second column of Table 4. 

The formula must be used with some caution in areas close to rapid 

changes in dip, as near a synclinal or anticlinal axis, for in most oil 

fields such folds are of the similar rather than the parallel type.

If the rate of dip only is known, it is possible also to determine the 

horizontal distance between contours for any given contour interval 

by the formula d I cot a, in which d = distance between contours, 

/= contour interval, and a = angle of dip. Table 4, in the third and 

fourth columns, gives the results obtained from the use of this formula 

for contour intervals of 100 and 500 feet.

The producing area of a dome or anticline in which the beds have 

steep dips is very small, because oil and gas do not extend through 

large vertical intervals in any sand, and the horizontal distance from 

points high on such a rock fold to points below the level at which oil 

and gas are present is short. Steep dips also cause difficulties in
U. S. GEOLOGICAL SURVEY BULLETIN 756 PLATE VII

Structure contours, interval 100 feet

v- Ov \>x>v x:i vxV^-T^ - $&<

MAP OF THE LOST SOLDIER DOME, WYOMING

Showing areal geology and structure of the Wall Creek sand
U. S. GEOLOGICAL SURVEY BULLETIN 756 PLATE VIII

I

1 

N

Feet

100- 

200- 

300- 

400- 

5OO60O70O8OO9OO1,OOO1,100- 

1,200- 

1,300- 

1,4OO1,500- 

1.600- 

1,700-

1,800- 

1,900-

2,OOO2,1OO2,200- 

2,300- 

2,400- 

2,500-

2,600- 

2,700- 

2.800- 

2,900- 

3,000- 

3,100- 

3,2OOr 3,300- 

3,400- 

3,5OO - 

3,600- 

3,700- 

3,800 

3,900 

4,000 

4,100 

4,200 

4,300 

4,400 

4,500 

4,600 

4,700 

4,800

Jair Oil Co. Produc 

IVell No. 22 C< 

E. J sec. 11, Vy 

T. 26 N., Sec. 

R. 90 W. I

-.,.; . . . Brown (IO bbls. 

 showing at 75)

 ----- Broivn

 =-^= Black

---:'-^. \l8"ho/e 

__..._ Browni fit /I of oil 

----- \at229'

 Evriv.'.s:- Brown, oil 

i-vSSiia (ho/eft/// of oil) 

 Gray 

:'; : '. ' . : . £ ,<; Cray, of/

 Gray 

: :. ',:.:..'. ':'. Gray

 Broivn

:.';. ;.:'..'.'.'. :.'.'. Brown, oil 

&*WW&i (hole full of oil)

. .v.v.v.v Gray

 i-.-i'--------.-. Brown 

 Dark

 ±~-~X. Blue

 . . ;.::::'.'.: Gray

 Blue

(

Little oil ana1 

- Blue

Sii&HSSS 'Gr&y, oil 

at 1112

' ^"rrr^^ Dark 

 . dray

 ....- ; Gray

t - Light, bentonite 

.: - '-' Darff

r.--^v.;y.;;.;. uark . 

v.-:r.-;W- : rBentomte

W^F: Dark

 . . '. .'.'.'. . .'. Gray 

 : . . . ; : /. . Dark(oi/j

ers&R 

>rporati 

tell No. 

7.T. 26 

1. 89 W

 -

 _

... ---^-

SECTS 

£^g

Er^EE

 - 

«i

efiners 

on Kaso 

1 V 

N., NE 

T. 26

Cray 

irown 

Blue

Gray 

3/ue

Gray 

Dark 

Gray

Dark gray 

Dark

S5/$i> 

Oark 

lark gray 

Gray 

3rown 

Gray 

Brown

Gray

Brown

Blue

Brown

Gray 

^Muddy blue

Brown 

Gray

Black 

Brown

Gray

Gray 

Blue 

Gray

Gray

Black

Black 

-Gray

Gray

ming 0 

tell No. 

3. i sec. 

N..R.

s-stjCTSST?

Dark 

Gray (tittle gas at 273S')

 Show of oil

 Show ofoil

Produc 

il Co. Co 

1 W 

34, Sec. 

38 W. 1

Dark 

3rown

lop of Frontier 

formation

Dark

Gas, 7,000,000 cu.fi. 

Dark

Gray 

Dark

Dark 

Derk

Dark 

Dark j bentonite

Dark

Gas, 4O,OOO,OOO cu. 

Blue

Brown Varicolored 

Oark 

l&rico/ored

Purple 

Black, bentonite

Dark, bentonita

Gray, bentonite 

White, bentonite 

Varicolored

Dark

Blue 

Gray 

Blue

ers&R 

rporatic 

ell No. 

25, T. 2 

El. 87 W

 C.-IL' ,'.* '.*.'..

efiners Gener 

>n Co 

4 W 

BN., SW.J 

T. 25

Blue

Gray 

Gray 

Gray

Blue 

Gray (show ofoil)

Blue

Show ofoil 

Gray

Blue 

Dark

Brown and b/ack

Gray and brown 

Brown 

Gray

al Petrc 

rporatic 

ell No. 

SW. is 

N., R. f

-----

leum 

>n Em< 

1 W 

sec. 9, Sec. 

36 W. E

3/ue 

3/ue

"iray 

3/ue

Brown 

3lue

Blue 

Blue

Blue 

Gray

Gray

Show ofoil

Gray 

Gray

Brown 

Gray

Gray 

B/ue, light

Blue

Blue (oil 

and gas) 

Brown

6/i/e

Gray 

Blue 

Gray

Black

-Brown, gas 

-Gas -Gas about 30,000,000 cu. Feet ^Gas

EXP

c

SE

Calc

L 

C

LANATION

 3^777 3^ n

Soi

jandsto

--=r-^r--=.

 -=-.=

Clay

Shale

Si^-

jndy sh

. ' , e=r

ne

:

i

ale

aceous shale

^ stj;**^*^

Shell

X

I

.imestone 

Slate

;

on^lomerate

jry Oil 

ell No. 

8, T. 25 

t. 86 W

 cr.Tjj'j^gTCg; 

-1 ' " ' Si^Ii

U'liiji.i'.-^

*_

"1 "aiJ--'n-1

^^v^v.-

.... - . 

:TT ;EI

.... _" '

,1; i;i!i ;r,i',i'i

..... 

 

 - -rr-

...... 

ffi^r-

__^

I ' ' ' i ' ! ' 1 '

SSig^V:^^

Kentu 

Co. 

1 W 

N.. Sec. 

1

Gray

Brown 

Blue

Brown 

Gray 

Dark

Brown 

Dark

Blue

3/ack

Brown

Blue 

Black

Gray 

Gray 

Gray

Dark 

Dark.hard 

Black 

Dark 

Brown

Gray 

Dark

Dark 

Dark

Dark

Dark 

Gray

Dark

Brown 

Brown

Brown

Horizon of gasproducing sand

Black 

Brown

Black

Black 

Light u

Blue 

u

Black

Brown

Show ofoil and gas 

Brotvn

Black

Black 

Considerable oil

Black

Wall Creek sand 

Black

Dark (oil and $as) 

Black

cky-Wy 

Oil Co. 

tell No. 

2,T. 24 

El. 87 W

 ,- ; T..-T 

±^-

^^^ 

 I ' r

' ' 

=-^-.-^r

-T-1 ^"

5=^

m

i ' B , , i

1 ' 1= -i_ . i= ^ 

^

S 

B

^EpE

: .y.-j^hH-r

 .;.,» ,.'.

?^7?fif^-^

oming 

Kaso 

? W

N., Sec.

Blue

Blue

Blue 

Steel-gray

Steel-gray

Steel-gray 

Steel-gray

Gray 

Dark

jray 

Blue 

Blue

Blue 

Blue

Black (trace ofoil)

Blue 

Good show ofoil

Gray 

Gray

Gray (show ofot/j

Gray 

Gray, rcryhard

ming 0 

tell No. 

2, T. 25 

*. 89 W

New Y 

il Co. Mid we 

3 W 

N , Sec. '.

Yellow 

Brown

Gray

Blue 

Vhite 

Gray

Brown 

Gray

Gray

Dark 

Dark gray 

Gray

Gray 

Brown 

Gray

Gray 

Black

Gray

^i::^:; Li$ht fry

- - Black 

l^^^n Light gray

ork Oil 

st Refin 

tell No. 

31, T. a 

*. 88 W

in 7:1: ,:. ,

£ft:

 , 

]o. and 

ing Co. 

1

1 N.,

Brown 

Gray

Blue

Brown

Blue

Gray

Black

Black

Black 

Gray

Dark

Gray 

'Black

-Pink 

Blue

White

Gray

Gray

Gray (jhoceneurots ancf, 

Ostreo, congests, fragments)

Gray, hard

Gray

Gray (JnocercurtiLS and , . OslnXL. conyesta. fragments)

Gray (ln.ocera.mus and _ . , 

 ^ Ostreo, c<on.</estci fragments)

Dark gray

Dark gray

Gray 

Gray (show ofoil)

Gray (Inocerosnus fragments) 

I,OOO,OOO cu. ft. of gas

Blue

Black

Black 

Black

Dark

Light (some bentonite)

Bentonite shale 

Dark

Light (some benton/tej 

Dark

Light (some gasj

Dark 

Black

* * * * r * 

 « * 

 * » 

* * * * * » 

 : :

* *

GRAPHIC LOGS OF WELLS IN THE LOST SOLDIER-FERRIS DISTRICT, WYOMING
LOST SOLDIER DOME. 33

well-log correlation unless they are taken into consideration. Some 

operators, even where the dip was known, have apparently failed to 

realize this effect of steep dips. The amount of this effect that is, 

the increase in depth due to the dip for any horizontal distance is 

expressed by the formula e = d tan a, in which e = increased depth, 

d = horizontal distance, and a = angle of dip. Results obtained 

from the use of this formula are given in the fifth and sixth columns 

of Table 4.

TABLE 4. Effects of dips at certain angles on vertical thickness, distance between 

contours, and depth to a bed.

Angle of dip (a).

1°.........................................

5°. ........................................

10°.........................................

15°........................................

20°........................................

25°........................................

30°........................................

35°........................................

40°........................................

45°........................................

50°........................................

55°........................................

60°........................................

Vertical 

thickness (t) 

of a bed 100 

feet thick 

(T= 100 feet; 

Z=100

sec o).

Feet. 

100.01 

100. 38 

101.54 

103.58 

106. 42 

110.34 

115.47 

122.08 

130.54 

141.42 

155.57 

174.34 

200.00

Distance between contours (<2=/coto).

7=100 feet.

Feet. 

5,729 

1.143 

567 

373 

274 

214 

173 

143 

119 

100 

84 

70 

57

7= 500 feet.

Feet. 

28,645 

5,715 

2.835 

1,865 

1,370 

1,070 

865 

715 

585 

500 

420 

350 

285

Increase in depth to a 

bed (e=d!tana).

<J= 100 feet.

Feet. 

1.75 

8.75 

17.63 

26.75 

36. 40 

46.63 

57.73 

70.02 

83.91 

100.00 

119. 18 

142. 81 

173,2

<Z=lmile.

Feet. 

92.4 

462.1 

930.9 

1, 412. 4 

1,921.9 

2,462.0 

3,048.1 

3, 679. 0 

4,430.4 

5,280.0 

6,292.7 

7,540.4 

9, 145. 0

OIL AND GAS FIELDS. 

LOST SOLDIER DOME.

SURFACE GEOLOGY AND STRUCTURE.

The Lost Soldier dome, the first structural feature to be proved 

oil-bearing in this district, is in the northeastern part of T. 26 N., R. 

90 W. It is elongated in a N. 30° W. direction and is fairly symmetrical. Its presence is well indicated by the partly surrounding 

hogback escarpment of the Mesaverde sandstones, which is well 

developed to the southwest, south, and southeast and also to the 

north and northwest. (See PI. V, A, B.) This hogback rim is the 

only prominent indication of the presence of a dome. The soft 

sandstone and thin limy sandstone that occur in transitional beds at 

the top of the Niobrara formation also crop out in a circular belt 

within the Mesaverde rim, but their presence would not be noted 

except by the trained observer. The boundary line between the 

Niobrara and the Steele marked by these sandstones is well indicated 

in a few places, especially in the hill near the north quarter corner of 

section 14 and in the low ridge and hills north of and parallel to the 

creek at the north side of the oil field. (See PL VII.) The highest 

part of the dome, which lies within this inner belt of sandstone, is
34 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

composed of Niobrara shale, and its flanks, out to the Mesaverde 

rim, of the Steele shale.

The apex of the dome lies immediately north of the west quarter 

corner of sec. 11, T. 26 N., R. 90 W., where the Wall Creek sand, 

the top sandstone of the Frontier formation, was found at a depth 

of 239 feet, and oil in the Muddy sand, the upper sandstone of the 

Cloverly, was reached at 1,375 feet.

The dome is modified on the east and north by numerous small 

radiating faults whose presence was determined where they cut the 

sandstone beds at the top of the Niobrara shale. They may be 

much longer than is shown on the map, but their length could not 

be ascertained in the field. Similar faults may occur on' the west 

and southwest sides of the dome, but as no rocks are exposed in 

these localities their presence could not be determined. The Mesaverde rim is cut by at least one fault on the northwest side of the 

dome. All these faults have probably had considerable influence on 

the stratigraphic distribution of the oil by permitting its migration 

into open fissures in the Mowry shale and into the porous Frontier 

sands.

DRILLING OPERATIONS.

By the end of 1921 the Lost Soldier field had 32 producing wells, 

of which 20 obtained their oil from the Wall Creek sand only (first 

Frontier sandstone), 3 from the first and second sands, 3 from deeper 

sands in the Frontier formation, 3 from the Mowry shale, and 3 from 

the Muddy sand. The first well to reach the Muddy sand encountered 

oil in three distinct sands of the Frontier formation, as indicated in 

the graphic log of this deeper test well given on Plate VIII.

When completed several of the earlier wells drilled to the Wall 

Creek sand were reported to have yielded more than 500 barrels

daily, but in the summer of 1920 the average daily production was 

about 50 to 70 barrels. At that time many of the shallow wells in 

the Wall Creek sand were producing considerable quantities of water, 

which was decreasing their output of oil. These wells could undoubtedly be profitably deepened so as to obtain oil from the lower 

sands of the Frontier.

.The three wells obtaining their oil from the Mowry shale are the 

Hughes Oil Co.'s well, in the southwest corner of sec. 2; the IllinoisWyoming Co.'s well No. 2, in the E. £ NW. { sec. 11; and the Bair 

Oil Co.'s well No. 33, an offset to the Illinois-Wyoming well. The 

Bair Co.'s well flowed at a rate of about 500 barrels a day when first 

drilled in.

The first well to reach the Muddy sand was the Bair Oil Co.'s well 

No. 22, which is on the apex of the dome. Its initial flow was estimated to be about 1,500 barrels a day. The Muddy sand had been 

penetrated by two other wells (Nos. 29 and 34) prior to 1922, but these
LOST SOLDIER DOME. . 35

two wells are not so located as to indicate the probable extent of 

its productive area. It would seem reasonable to expect that this 

area would be as large as that of the Wall Creek sand, if not larger. 

Mr. E. W. Krampert, geologist for the Kasoming and Bair companies, informed the writers of a peculiar condition in the oil reservoir on this dome that was brought to light by a curtailment of 

production during the fall of 1921. Prior to this tune the shallow 

wells in the Frontier sands were producing considerable quantities 

of water, and at an increasing rate. One of these wells was pumping as much as 80 per cent of water. When the production of the 

field was curtailed by the shutting in of the Muddy sand wells, an 

immediate improvement was noted in the production from the 

Frontier sand, which increased about 300 barrels daily, and this 

increase was accompanied by a marked dropping off in the quantity 

of water obtained. In the well that had been producing 80 per cent 

of water the water was reduced to less than 10 per cent. The intercommunicating character of the Muddy and Frontier sands, as above 

described, indicates that the small faults that cut the dome provide 

open passages through which the pressure in the Muddy sand is 

transmitted to the higher sands. When this pressure is removed 

from the Frontier sands by the flowing of the Muddy sand wells 

the edge water in the Frontier sands is enabled to crowd into the 

wells.

UNTESTED DEEP SANDS.

It is possible that oil hi commercial quantity may also be found in 

sands below the Muddy. The conglomerate at the base of the 

Cleverly, which is about 150 feet stratigraphically below the Muddy 

sand, is probably more porous and even better suited as a reservoir 

for oil. At depths of 200 to 700 feet below th.e Cloverly in the Whisky 

Gap region there are two sandstones, which occur in the Sundance. 

Although neither of them is known to be oil or gas bearing in other 

parts of Wyoming, it is possible that oil and gas may have accumulated hi them here.

The Triassic and Permian red beds, whose sandstones could well 

act as oil and gas reservoirs, underlie the Sundance, and the equivalents of the Embar, which produces oil in several Wyoming localities, 

would probably be reached at a depth of 3,650 feet on the apex of 

the dome. The Tensleep sandstone would probably be encountered 

at about 4,050 feet, and the Madison at about 4,450 feet.

CHAEACTEK OF OIL.

The oil from the Wall Creek sand has a paraffin base and a specific 

gravity when fresh of about 0.8675 (31.4° Baum6). According to 

the analyses on page 54, it contains about 19.3 per cent of naphtha 

and gasoline (the fraction distilled below 200° C.), 18.1 per cent of
36 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

kerosene (the fraction distilled between 200° and 275° C.), 18.65 per 

cent of gas oil (vacuum-distillation fraction below 225° C.), 23.5 per 

cent of lubricating oils (vacuum-distillation fraction between 225° 

and 300° C.), and about 18 per cent of residue. Its viscosity increases so greatly in cold weather that it could not be piped to the 

Fort Steele loading station through the 4-inch pipe line during the 

period.from November, 1919, to April, 1920.

No samples were obtained of the oil from the Muddy sand, but in 

view of the intercommunicating character of these two reservoirs it 

is probably very nearly the same as that from the Wall Creek sand.

PRODUCTION.

The distance of the Lost Soldier field from transportation routes 

did not warrant^ active development and production immediately 

after oil was discovered. Prior to the completion of the pipe line, hi 

April, 1919, the product was held by two steel storage tanks. Until 

August, 1920, when the first well reached the Muddy sand, the oil 

marketed was derived entirely from the Frontier sands.

TABLE 5. Petroleum produced and sold in the Lost Soldier field, 1916-1921,

in barrels.

Year.

1916...........................

1917...........................

1918...........................

Number

of wells

producing 

at end

of year.

3

4

14

Barrels.

871

2.683

100,188

Year.

1919...........................

1920...........................

1921...........................

Number

of wells

producing 

at end

of year.

20

25

28

Barrels.

174.431

206,903

380,811

865,887

WERTZ "DOME." 

SURFACE GEOLOGY AND STRUCTURE.

East of the Lost Soldier dome the valley of Lost Soldier Creek is 

flanked by Mesaverde escarpments, somewhat obscure on the south 

but prominently developed on the north, in which the beds of rock 

dip away on either side. The dips in these escarpments indicate an 

anticlinal fold with its middle in the valley, but the configuration of 

the crest can not be ascertained, as the entire valley is filled with 

alluvium and dune sand. Near the south side of T. 26 N., R. 89 

W., the south escarpment swings abruptly southward and the eastward extension of the anticlinal fold is very obscure.

The northwest end of this fold, in sees. 1 and 12, T. 26 N., R. 90 

W., and sec. 6 and parts of sees. 5, 7, and 8, T. 26 N., R. 89 W., is 

indicated by the dip and strike of bedding planes in the Steele shale. 

In addition the Steele shale contains a thin bed of limy argillaceous
WEKTZ "DOME." 37

yellowish-brown sandstone, which though indistinct, can be traced 

across parts of sees. 1 and 12, T. 26 N., R. 90 W. This bed was of 

material aid in determining the probable structure. The crest line of 

the fold is fairly well denned in the northwestern part of sec. 7 by 

the change in direction of the dips determined on the shale bedding 

planes. The position of the crest line and the configuration of the 

fold toward the southeast are not determinable, because in that 

direction the rocks are concealed under a cover of alluvium and 

dune sand.

The evidence described above was used by the Producers & Refiners Corporation for locating a test well in the northeast corner of the 

SW. i sec. 7, T. 26 N., R. 89 W., at the edge of the shale outcrops 

and near the crest line. The success of this well in encountering a 

little oil and large quantities of gas has demonstrated the reliability 

of the geologic evidence afforded by the exposed rocks.

Whether or not the accumulation of oil and gas here is caused by 

a local high point or dome on the anticlinal fold can not be ascertained by an examination of the exposed rocks. Notwithstanding 

this uncertainty, the indeterminate structural feature in the vicinity 

of the well is known as a "dome" among the local oil fraternity and 

bears the appellation "Wertz dome."

The position of the inferred contours on the map (PL I) gives the 

Wertz "dome" some prominence for a short distance southeast of 

the discovery well. The inference that closed contours may be 

drawn on this southeastern extension of the "dome" is based entirely on the slight change of strike in the northern Mesaverde escarpment, in sec. 9, T. 26 N., R. 89 W.

DRILLING OPERATIONS.

The gas well of the Producers & Refiners Corporation in the northeast corner of the SW. J sec. 7, T. 26 N., R. 89 W., was the only 

one drilled on the Wertz "dome" before the end of 1920. The Wall 

Creek sand and the other sands at the top of the Frontier formation 

were found at depths of 2,145 to 2,530 feet, and a small showing of 

gas was encountered in the lowermost of them. (See log B on PI. 

VIII.) In the Mowry shale at a depth of 3,140 to 3,175 feet a very 

good showing of oil with a gravity of 36° Baume", according to a rough 

field test, was encountered, and at times the gas pressure was sufficient to force the oil to the surface. Enough oil was obtained for a 

time to supply the fuel for the deeper drilling, and after the well 

was completed to the gas sand it produced between 400 and 500 

barrels of|oil monthly from the Mowry. The Muddy sand, at the top 

of the Cleverly, was reached at 3,410 feet. It gave a showing of 

gas, and when it had been penetrated 35 feet the pressure became
38 OIL AND GAS, LOST SOLDIER-FERBIS DISTEICT, WYO.

so great that the tools were blown out of the well. An open-flow 

volume of 30,000,000 cubic feet and a few hundred gallons of casinghead gasoline daily were reported in trade journals as the productive 

capacity of the well.

Why the Muddy sand should yield oil on the Lost Soldier dome, 

only a few miles distant, and nothing but gas here may be explained 

by the possible absence in the Wertz "dome" of open passages like 

those in the Lost Soldier dome, which would permit oil to be fed upward into the sand.

Trade journals reported the completion of a second gas well during 

the summer of 1921. Until the fall of 1921 the gas of this field, like 

that of other fields in the district, had no market aside from its use as 

fuel in the field itself. Since the completion of the gas pipe line to 

Casper, late in 1921 the wells of this field, according to press reports, 

have supplied a large part of the gas transported by that line.

Further prospecting on this " dome" will seek to determine whether 

oil underlies the gas in the Muddy sand on the flanks of the uplift, 

whether any deeper sands contain oil or gas, and in how large an 

area the Muddy sand is productive.

It is altogether possible that oil exists in the Muddy sand beneath 

the gas, and according to press reports the gas apparently contains 

some of the heavier constituents that evaporate from oil. Whether 

or not oil is present in the Muddy sand on the flanks of the "dome" 

can be determined only by test wells drilled there. As the structure 

is indefinite along the axis of the fold to the southeast, it would seem 

advisable to drill either to the northeast or to the southwest of the 

discovery well. A few wells so spaced as to find the Muddy sand 

approximately 200 feet lower at successive points would soon determine whether or not it is oil-bearing.

Wells will probably be drilled to the lower sands to determine 

whether the basal conglomerate of the Cleverly and perhaps the sands 

of the Morrison and Sundance formations contain oil or gas. The 

basal conglomerate of the Cloverly should be encountered at about 

3,560 feet in the discovery well, and the sandstones belonging to the 

Morrison and Sundance at 3,800 and 4,300 feet. The Embar horizon 

would be found at about 5,675 feet and the Tensleep about 400 feet 

lower.

In determining the extent of the area in which the Muddy sand is 

productive, the first endeavor should be to sink test wells on the axis 

and in this way to determine whether or not there is a distinct dome 

in this vicinity. Should an eastward pitch be discovered, it would 

not require a great deal of additional drilling to ascertain the breadth 

of the productive area.
BUNKER HILL DOME. 39 

EASTWARD EXTENSION OF WERTZ "DOME."

Whether or not the anticlinal fold extends -eastward from the 

Wertz "dome" can not be determined by surface examination, but 

because the Mesaverde escarpment on the north continues eastward 

with its persistent northward dip, it seems reasonable to suppose that 

the anticlinal fold also continues southeastward and joins the Mahoney dome. Four wells have been drilled in the direction of this 

possible eastward extension of the anticline, but because the configuration of the crest of the fold is not determinable, the locations of 

the wells were chosen without close structural control, and the results 

obtained have been very discouraging. One of thse wells, drilled 

by the Lost Soldier Oil Co., is within three-quarters of a mile from the 

northern Mesaverde escarpment and about 3 miles from the southern 

escarpment a location, it would seem, far down on the north flank 

and certainly not near the crest of the fold. The three other wells, 

drilled by the United States Petroleum Corporation, although not 

located with any immediate control, nevertheless tested the middle 

region lying between the Mesaverde escarpments. The well in sec. 

16, T. 26 N., R. 89 W., reached the Wall Creek sand, which carried 

some gas, at a depth of 3,348 feet. Drilling continued to a depth of 

3,530 feet without finding additional showings. The gas in the Wall 

Creek was reported to amount to several million cubic feet daily and 

to have been used in the further drilling of this well and the other 

wells of the company. The well in sec. 22, T. 26 N., R. 89 W., encountered the Wall Creek sand at 3,472 feet. The sand was recorded 

in the log as containing a showing of oil but no gas. The drilling 

continued in the Wall Creek to a depth of 3,600 feet, at which the 

well was abandoned. The company's third well, in sec. 26 of the 

same township, was drilled to a depth of about 1,600 feet and then 

abandoned before reaching the Wall Creek sand. From neither the 

surface geology nor the findings of the first two of these wells is it 

possible to determine whether any of them were located on the crest 

of the fold, or in which direction from any of them the crest may be. 

Further search for oil and gas along this anticlinal fold must proceed 

rather blindly. By drilling transversely on the fold in the neighborhood of the wells in sees. 16 and 22 it should be possible to locate the 

anticlinal crest with considerable accuracy.

BUNKER HILL DOME.

The Bunker Hill dome, in the southwestern part of T. 27 N., R,. 

89 E., northeast of the Wertz "dome," is the most clearly defined 

structural feature in the district. The outline of the dome is very 

definitely shown by the outcrops of several Mesaverde sandstones, 

which lack very little of completely encircling it. The fold is oval,
40 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

and its major axis trends northwest. Its apex lies at a point about 

800 feet east of the southwest corner of sec. 29, T. 27 N., R. 89 W. 

From this point the rocks dip rather gently in all directions but at 

somewhat larger angles to the north, northwest, and west than to 

the south and east. As mapped on Plate I its apex in the Frontier 

formation lies about 800 feet above the syncline to the southwest 

that separates it from the Wertz "dome" and about 600 feet above 

the Sand Creek syncline, to the northeast.

The dome has been eroded down so that a thin-bedded sandstone 

of considerable thickness is exposed, which is overlain by about 50 

feet of soft shale, and the resulting topographic form of the crest i& 

a very slightly modified reproduction of the structural form.

Only one test well had been drilled on the Bunker Hill dome 

at the time of this investigation. This well was drilled by the Kasoming Oil Co. in the northeast corner of the NW. i sec. 32, T. 27 N., 

R. 89 W., near the apex of the dome. It was reported to have been 

abandoned at the very slight depth of 827 feet without encountering any showings of oil or gas. As its mouth is about 500 feet above 

the base of the Mesaverde formation, which here has a thickness of 

about 785 feet, it passed through the lower 'sandstones of the Mesaverde and entered the Steele shale only in its last 300 to 400 feet. 

As the drill ascertained the oil and gas possibilities of only the Mesaverde sandstones it is obvious that the sands which are productive 

in the neighboring fields were not tested. The great depth of about 

6,700 feet to the Wall Creek sand, at the top of the Frontier, prevented the drilling of the well to this and lower sands.

As shown in the consideration of the G. P. field (pp. 46-47), it seems 

very probable that the producing sand there is considerably higher 

in the stratigraphic section than the Wall Creek and belongs tothe lower part of the Steele shale or the upper part of the Niobrara. 

If this correlation is correct, the G. P. sand should be found within 

reach of the drill on the apex of the Bunker Hill dome at a depth 

of about 5,300 feet.

MAHONEY DOMES. 

SURFACE GEOLOGY AND STRUCTURE.

Attempts by prospectors to find other domes in the basin between 

the Rawlins Hills on the south and the Ferris and Seminoe mountains on the north soon led to the discovery of a local area of Niobrara 

shale in sees. 33, 34; and 35, T. 26 N., R. 88 W. and sees. 3 and 4, 

T. 25 N., R. 88 W. This area of Niobrara shale is bordered on the 

east, south, and west by an inconspicuous rim of the thin beds of 

limy argillaceous yellowish sandstone that mark its top and on the 

north by dune sand. The beds of yellowish sandstone dip away 

from the central shale area at gentle angles, and in a few places the
MAHOXEY DOMES. 41

overlying Steele shale is exposed beyond the riin. These features, 

in conjunction with the northward dip of the Mesaverde 2 miles to 

the north, clearly indicate the presence of a dome, the west one of 

the two Mahoney domes.

The configuration of the top of this west dome has been well 

eatablished on the east, south, and west, where the dip of the beds 

is gentle (about 5°), but the cover of dune sand has made the contouring of the north flank very uncertain. As the Mesaverde is so 

near on the north, in sees. 21 and 22, T. 26 N., R. 89 W., it would 

appear that the dip in this direction must be rather steep. The 

surrounding rim of yellowish beds marking the top of the Niobrara is 

broken by numerous small radiating faults similar to those in the Lost 

Soldier dome. The extent of these faults within and beyond the 

obscure rim of yellowish beds is not known, because of the absence of 

exposed rocks in which dislocations can be discerned.

DRILLING OPERATIONS.

The discovery well on the west Mahoney dome was drilled in the 

southwest corner of the NE. i sec. 34, T. 26 N., R. 88 W., by the 

Kasoming Oil Co. (See log C, PI. VIII.) It passed through the 

Wall Creek sand and the other sands of the upper part of the Frontier 

formation at depths between 865 and 1,215 feet and encountered 

gas in sand at a depth of 1,130 to 1,140 feet. The yield of this gas 

was estimated at about 7,000,000 cubic feet a day. Early in the fall 

of 1919, at a depth of 2,160 feet, the drill entered the Muddy sand and 

struck gas which was reported to be of the "dry" variety and was 

estimated to have amounted to a daily open-flow yield of 30,000,000 

to 50,000,000 cubic feet. The means for controlling this large gas 

flow were inadequate, and the weU blew wild. Early in the morning 

of October 1, 1919, lightning ignited the gas, and it burned for 27 

days before being put out. The means used to extinguish the fire 

are interesting. Water was ponded about the well to cool the ground 

and iron, and steam from eight field boilers was directed at the 

mouth of the well. This alone had no effect in extinguishing the fire, 

so a 25-pound charge of dynamite was rigged up to explode close to 

the well mouth. The concussion of the explosion was strong enough 

to stop or slow down the flow of gas momentarily, so that the steam 

could snuff out the flames.22

A new derrick was then erected over the well, and the gas sand 

was cased off for a deeper test. The hole was drilled to 2,525 feet. 

The log of this deeper hole does not conform closely to the section 

as exposed 6 miles to the north. There the basal conglomerate of 

the Cleverly lies 125 feet below the Muddy sand, but the log of the

23 Reported in personal communication from E. W. Krampert.
42 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

Kasoming well records only 30 feet of shale between the Muddy and 

a 10-foot bed of varicolored conglomerate. It is possible that a 

small inclined fault similar to those mapped in sections 3 and 4, to 

the south, cuts the beds immediately below the Muddy sand and that 

the well encountered the conglomerate displaced in an upthrown 

block at a point where the conglomerate itself was in a wedge form 

and presented a vertical thickness of only 10 feet. This supposition. 

is slightly supported by the log of the deeper part of the well, which, 

includes first 6 feet of "dark shale" followed by "16 feet of varicolored 'shale with some pebbles." The pebbles might very probably be loosened pebbles from the conglomerate ground into th& 

underlying shale adjacent to the plane of dislocation. A little gas 

was encountered in the shale that contains pebbles. The rocks 

below this bed to a depth of 2,455 feet correspond to the Morrison, 

and below this formation a 10-foot "lime" was encountered, which 

very probably is a limestone bed of the Sundance formation. Drilling continued to a depth of 60 feet below this "lime." After the 

casing that shut off the Muddy sand had been withdrawn considerable trouble was experienced in closing the well, and it blew wild for 

several months before being brought under control on August 28, 

1920.

In the summer of 1921 the Kasoming Oil Co. completed its second, 

well in the southeast corner of sec. 28, T. 26 N., R. 88 W., where the 

pay sand was found at a level 200 feet lower than in the discovery 

well. This well was drilled in an attempt to find oil in the Muddy 

sand at a lower level on the dome, but, like the discovery well, it 

encountered only gas. The open flow was estimated at 35.000,00ft' 

cubic feet a day.

In sec. 4, T. 25 N., R. 88 W., on the southwest flank of the dome,

the Midwest Refining Co. drilled a well which had to be abandoned, 

because of drilling troubles during the summer of 1920 before reaching the Muddy sand. A new well was then started, but it was. 

abandoned at a depth of about 2,690 feet in August, 1922.

Believing that the dome tested by the Kasoming Co.'s well was but 

a local "high" on a fold which parallels the Sand Creek syncline and. 

that it extended eastward, the Ohio Oil Co. drilled a well in the 

southwest corner of the NW. i sec. 36, T. 26 N., R. 88 W., hoping, it 

is reported, to find the Muddy sand at such a level that oil rather than 

gas would be struck. The sand was reached in the early part of July, 

1920, at a level 318 feet lower than that in the discovery well, and,, 

contrary to expectations; gas was encountered with an open flow of 

30,000,000 cubic feet daily and a closed rock pressure of 1,040 poundsto the square inch. A second well was drilled by the same company 

about a mile farther east, in the southeast corner of the NE. £ of the 

same section. This well reached the sand at a level 55 feet below that
FEBBIS DOME. 43

in the first well and likewise obtained only gas, with an open flow of 

30,000,000 cubic feet a day and a closed rock pressure of 1,000 pounds 

to the square inch.

The area around these two gas wells is devoid of rock outcrops, 

but the underground information supplied by these wells and by the 

log of the Wyanna Oil Co.'s test well in the southwest corner of the 

SE. i sec. 25, T. 26 N., R. 88 W., appears to indicate that there is a 

second dome on the east-west anticlinal fold, east of the one indicated by the Niobrara shale area, and that the two domes are 

separated by a very shallow syncline. Because of the ill-defined 

nature of the upfold in this vicinity, no special name will be given to 

this second dome in this report, but it will be referred to simply as 

the east Mahoney dome

The deeper drilling of the discovery well appears not to have found 

the basal conglomerate of the Cloverly in its normal state, and hence 

the writers believe that this conglomerate has not received a conclusive 

test. It should normally be found about 125 to 150 feet below the 

Muddy sand.

There is still some possibility that drilling-on the east Mahoney 

dome to depths greater than that reached by the discovery well may 

find oil. The lower sandstones of the Sundance and the underlying 

red beds extend to a depth of about 4,550 feet. The top beds equivalent to the Embar should be found on the apex of the dome at a 

depth of about 4,150 feet, the Tensleep should follow at a depth of 

about 4,550 feet, and the Madison at 4,950 feet.

FERBIS DOME. 

SUEFACE GEOLOGY AND STEUCTUEE.

Centering in sec. 25, T. 26 N., R. 87 W., is the crest of the Ferris 

dome, an elongated fold whose axis extends in nearly a straight 

northwesterly direction from a point near the southwest corner of 

sec. 31, T. 26 N., R. 86 W., into sec. 23, T. 26 N., R. 87 W. (See fig. 

2.) The rock exposures of this vicinity are very few in number, but 

with the assistance of information supplied by well logs it has been 

possible to outline the general configuration of the fold.

The Niobrara shale, carrying characteristic fossils and dipping in 

opposite directions on either side of the anticlinal axis, is exposed at 

several places near the center of the E. $ sec. 25, T. 26 N., R. 87 W. 

The transition beds at the top of the Niobrara are probably rep 

resented in the exposures near the middle of the north line of the 

NE.i sec. 25, T. 26 N., R. 87 W. This is the only point where the 

contact between the Niobrara and Steele shales is exposed, but it is 

thought that beneath the concealing dune sand the Niobrara shale 

occupies approximately the area within the 6,000-foot contour line 

as given on Plate I.
44 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

To the northeast the adjacent syncline is fairly well indicated by 

dips and strikes determined on bedding planes in scattered outcrops 

of shale in sec. 24, T. 26 N., R. 87 W., and sec. 19, T. 26 N., R. 86 W., 

and farther south by shale exposures and the comparatively extensive 

outcrops of a few thin beds of hard limy argillaceous sandstone, of 

which one could be mapped across sees. 27, 28, and 29, T. 26 N., 

R. 86 W. This one mappable bed is considered to be in the Steele 

shale about 2,590 feet above its base. It seems reasonable to suppose 

that this syncline northeast of the Ferris dome is a continuation of 

the Camp Creek syncline, to the west, and that toward the southeast

R.87W. R.86 W.

3 MILES

For explanation ofsvmbots see Plate I 

FIGURE 2. Map of the Ferris dome.

it joins with the syncline indicated by the outcrops of the-Mesaverde 

formation in sees. 2, 3, and 4, T. 25 N., R. 86 W.

The southeast end of the elongated Ferris dome is fairly well outlined by the information obtained from the logs of the wells in sees. 

30 and 31, T. 26 N., R. 86 W., and sec. 36, T. 26 N., R. 87 W. The 

configuration of the northwest end of the dome, however, is very 

uncertain. There is no information available.to indicate the direction of its crest across sec. 23, T. 26 N., R. 87 W. It is believed, 

however, as indicated on the map, that the axis turns westward 

along the south margin of sec. 23 and that farther west it bends 

slightly toward the southwest and joins the east-west axis of the 

Mahoney dome.
FEBEIS DOME. 45 

DRILLING OPERATIONS.

The Wall Creek sand comes within less than 300 feet of the surface 

at the apex of the Ferns dome, which is near the center of the E. £ 

sec. 25, T. 26 N., R. 87 W. This and the other Frontier sands, 

which together here occupy an interval of about 290 feet, contain 

but small showings of oil and gas, and commercial quantities are 

found only at greater depth. (See log D, PI. VIII.) The oil 

obtained in the first three wells in sec. 25 was encountered in the 

Mowry shale (probably in crevices), but the gas in the three wells 

drilled near the center of sec. 25, near the center of sec. 26, and in 

the northeast corner of sec. 36 comes from the Muddy sand, at the 

top of the Cloverly formation.

Thus far no test well has reached the basal conglomerate member 

of the Cloverly, unless it is the Producers & Refiners Corporation's 

well No. 2, in sec. 36, T. 26 N., R. 87 W., which was drilled to a 

depth of 2,815 feet, or 1,635 feet below the top of the Wall Creek 

sand. It is impossible to correlate the lower part of the log of this 

well with the exposed stratigraphic section, and hence the uncertainty as to what beds were reached. Minor faults such as affect 

the Lost Soldier and Mahoney domes are probably present also in the 

Ferris field, and may cause the apparent irregularity in well logs. 

The information to which the writers had access does not indicate that 

the oil or gas bearing possibilities of the beds below the Muddy have 

been tested. The conglomerate of the Cloverly formation should be 

found at depths ranging from 125 to 150 feet below the Muddy sand. 

The sands of the Sundance and Morrison formation lie at depths 

of 1,825 to 2,325 feet below the surface on the apex of the dome, 

and the Embar, Tensleep, and Madison at depths of about 3,700 

4,100 and 4,500 feet, respectively.

PRODUCTIVITY OF WELLS AND QUALITY OF THE OIL AND GAS.

The three oil wells of the Ferris field are small pumpers and have 

an estimated combined daily production of 65 barrels. Because they 

had no access to a market they were not in active operation until 

the winter of 1920-21, when the pipe line reached this field.

Petroleum produced in the Ferris field, 1919-1921.

Barrels.

1919._........._.__................................. 2, 390

1920................................................ 10,088

1921 (Jan. 1 to Nov. 30).............-................ 16, 740

29, 218

The initial daily open-flow capacity of the well in the northeast 

corner of sec. 26; T. 26 N., R. 87 W., was reported to have been 

5,000,000 cubic feet; that of well No. 4, in sec. 25, 13,000,000 cubic

79079 24f 4
46 OIL AND GAS, LOST SOLDIEKr-FERRIS DISTRICT, WYO.

feet; and that of the well in the northeast corner of sec. 36, 23,000,000 

cubic feet. The capacity of the well in the center of sec. 26 was 

reported to be rather small. The closed rock pressures of these 

wells were not ascertained by the writers but are said to be comparable to those on the Mahoney domes.

The oil obtained here from the Mowry has a specific gravity of 

about 0.827 (39.3° Baiiine") and is thus of considerably higher grade 

than that from the Wall Creek sand in the Lost Soldier field. From 

the analyses given on page 54 the gasoline and naphtha content 

amounts to 33.1 per cent (fraction distilled below 200° C.); kerosene, 

13.6 per cent (fraction distilled between 200° and 275° C.); gas oil, 

13.6 per cent (vacuum-distillation fraction below 225° C.); lubricating oil, 18.7 per cent (vacuum-distillation fraction between 225° and 

300° C.); residue, about 20 per cent.

As the gas from the Muddy sand is known to contain constituents 

that are condensable to gasoline, it is the opinion of some operators ' 

that there is a possibility of finding oil in the Muddy sand on the 

flanks of the dome below the gas level. Press reports during the 

winter of 1921-22 indicated that some of the gas wells were yielding 

sufficient oil along with the gas to hamper in some degree the transportation of the gas.

Q. P. "DOME."

SURFACE GEOLOGY.

A pitching anticlinal fold crossing sees. 15 and 16, T. 25 N., K. 

86 W., is indicated by the dip and strike of the rocks in a nearly 

semicircular rim of Mesaverde sandstone which crosses sees. 4, 10, 15, 

16, 21, and 20 of the same township. The area within this encircling rim is entirely covered by dune sand, hence the configuration 

of the northwestward extension of this upfold can not be definitely 

ascertained. With the hope that the pitching fold indicated by the 

Mesaverde rim represents the southeastward extension of an elongated 

dome that might contain oil, the General Petroleum Corporation 

drilled a well hi the northwest corner of sec. 16 and, at a depth of 

3,020 feet, obtained oil that amounted to 300 barrels daily for a 

period of 14 days. The structural fold controlling this oil pool is ; 

called the G. P. "dome" by the local oil fraternity, after the initials 

of the corporation mentioned. Whether accumulation of oil here is 

caused by a dome, an anticlinal nose, a faulted and sealed sand, or 

a lenticular sand can not be ascertained from the present available 

information. A view across the field is shown in Plate VI, B.

STRATIGBAPHIC POSITION OF G. P. PAY SAND. .

Because the Wall Creek sand was the shallowest known producing , 

sand in the district it was at first thought that this was the pay I 

sand in the discovery well, but extrapolation of the dips in the Mesa-
G. P. "DOME." 47

verde rim makes it appear more probable that the G. P. sand lies 

between 1,200 and 2,000 feet above the Frontier formation. It is 

possible, however, that the dips increase rapidly within the escarpment rim and that the pay sand is considerably lower in the stratigraphic section, but it does not seem possible that the sand can 

belong to the Frontier formation, for that would necessitate am 

increase in the angle of dip within the escarpment rim from 9° to> 

more than 45°. If the dip of the rocks within the Mesaverde rim: 

remains nearly the same as that of the rim itself, then the pay sand 

should be considered to he between 1,200 and 2,000 feet above the 

Frontier formation, which would place it in the upper part of the 

Niobrara formation or in the lower part of the Steele shale. Only 

soft argillaceous sandstone and sandy shale zones are known to be 

present within this interval, and the best developed of these are the 

soft sandstones lying above and associated with the key beds that 

mark the top of the Niobrara, about 1,500 feet above the Wall 

Creek sand. This conclusion is further substantiated by the evidence derived from the somewhat uncertain correlation of well logs, 

discussed below. The correlation, however, is not clear, and hence 

the stratigraphic position of the G. P. sand can not be definitely 

known until more wells are drilled in the area between the G. P. 

and Ferris fields so that the sands can be correlated across this 

area with more certainty.

POSSIBLE FORMS OF STRUCTURE.

Because the configuration of the upfold can not be determined, 

on account of the absence of rock outcrops, several possibilities may 

be considered in an attempt to interpret the structure. Various 

forms of domes have been supposed for this area by different geologists. Some have considered the fold to be an east-west anticline 

parallel to the Table Hills syncline. The site of the well in sec. 13, 

T. 25 N., R. 87 W., seems to have been chosen on this supposition. 

Others have thought that it trends toward the Mahoney dome, and 

the wells in sees. 1, 2, 3, and 11, T. 25 N., R. 87 W., seem to have 

been so located as to test out this theory. The writers, however, 

believe that as the G. P. "dome" lies on the first upfold west of 

the syncline that crosses sees. 32 and 33, T. 26 N., R. 86 W., 'and 

sees. 4, 3, and 2, T. 25 N., R. 86 W., it should be considered the 

southeastward continuation of the structural fold on which the 

Ferris dome is situated. Tne difference of opinion over this point, 

however, can not well be settled until more wells are drilled tp 

increase knowledge of the underground conditions.

In the vicinity of the discovery well several others have been 

drilled. The General Petroleum Corporation in its second well in 

this field, near the center of the SW. \ SW. £ sec. 9, about 1,000 feet
48 OIL AND GAS, LOST SOLDIER-FERRXS DISTRICT, WYO.

north of the discovery well, encountered an oil-bearing black sandy 

shale at a depth of 2,863 feet (log E, PL VIII), or at an altitude about 

167 feet above that of the oil sand in the discovery well. The Sand 

Hills well No. 1, in the southwestern corner of the SE. £ sec. 9, encountered the G. P. sand at a depth of 3,168 feet, or 95 feet lower 

than in the discovery well. In this well a small quantity of oil was 

encountered, during the summer of 1920, and it was reported that on 

drilling deeper in 1921 other showings were found at 3,252 feet and 

3,818 feet.

Half a mile west of the discovery well, in the northwest corner of 

the NE. $ sec. 17, the General Petroleum Corporation drilled a well 

that went to a depth of 4,920 feet before being abandoned as dry. In 

the log of this well the driller recorded one thin sand and several 

"limestones" in the interval between 2,785 and 3,245 feet, and sand 

as forming most of the 90-foot interval between 4,445 and 4,535 feet. 

It is possible that this deep sand is the Wall Creek, and if so the uppermost of the "limestones" may be interpreted as the equivalent of 

the G. P. sand, if it is assumed that the dip in the rocks at this locality 

remains the same as in the Mesaverde rim to the south. It is possible, 

of course, that a radical change takes place in the local dip and strike 

of the rocks, which would require another interpretation of the deep 

sandstone and the "limestone" noted in the log.

In the SW. £ sec. 8 the No. 1 well of the Emery Oil Co. was drilled 

to a depth of 4,810 feet. (See log F, PL VIII.) ^Between 4,060 and 

4,375 feet the drillers recorded sand, and possibly this "sand" 

represents the Wall Creek and other sandstones at the top of the 

Frontier formation. The reasonableness of such an interpretation is 

enhanced because it seems that this sand should be correlated with 

the deep sand of the dry hole in sec. 17, noted in the preceding paragraph. If the sand found between 4,060 and 4,375 feet in the Emery 

well is the Wall Creek, then it is probable that the " brown shale and 

hard shells" recorded at 2,370 to 2,450 feet represent the G. P. sand.

Still farther west, in the northeastern corner of sec. 13, T. 25 N., 

R. 87 W., the Ohio Oil Co. drilled to a depth of 3,300 feet and encountered at 2,860 feet a sand which, if the dip of the rocks in this vicinity 

remains nearly the same as in the Mesaverde escarpment to the south, 

could well be the equivalent of the G. P. sand. If this and the 

previous correlations are correct the area within a distance of 1 mile 

from the Mesaverde rim shows no marked change in structure from 

the rim itself. Different correlations between the logs of these wells, 

however, would necessitate radical changes in the conception of the 

local structure.

The writers have considerable confidence in the well-log correlations given above and believe that the G. P. sand is one of the sands 

in the basal part of the Steele shale or the top of the Niobrara, which
G. P. "DOME." ' 49

lie about 1,500 feet above the Wall Creek sand. The structure here 

is therefore shown on the map (PL I) as that of an anticlinal nose. 

The positions of the 3,000 and 3,500 foot contours in this vicinity are 

altogether inferred. If Ihe well-log correlations are incorrect, or if 

the G. P. sand lies at some other horizon, then the structure of the 

G. P. "dome" must be quite different. From the uncertainties 

attached to the local conditions, it is obvious that the configuration 

of the G. P. "dome" can not be fully determined until more underground information is available through the drilling of additional 

wells.

It is likewise obvious that the controlling factor in the accumulation of the oil in this field is uncertain. It is not usual in regions so 

closely folded as Wyoming for oil to accumulate on anticlinal noses. 

The 3,000 and 3,500 foot contours, however, may have a local closure, 

and the oil found in sees. 9 and 16 may be that which would accumulate on the pitching end of a dome whose apex may be in sec. 9. The 

accumulation also may have been caused by a transverse fault 

cutting the sand northwest of the wells, with the result that the sand 

was sealed and this sealing prevented the oil from migrating farther 

up the rise. It is also possible that the sand is a local lens. In view 

of these uncertainties it is quite impossible to predict the extent of 

the productive area.

PEODUCTION.

The discovery well of the General Petroleum Corporation was rated 

a 300-barrel initial producer. The same company's second well, in 

sec. 16, its well in sec. 9, and the Sand Hills well were also good producers. A market for the oil was obtained late in the fall of 1920, 

when a pipe line to Fort Steele was completed. The gross production 

of the General Petroleum Corporation's wells is given below.

Petroleum produced in G. P. field, 1919-1921.

Year.

1919.................................................................................

1920.................................................................................

1921.................................................................................

Number

of wells producing at end

of year.

1

1

3

Barrels.

4,465

iq QOQ

74 199 '

The oil of the G. P. field is similar to that of the Ferris field and 

differs considerably from that of the Lost Soldier field. The detailed 

analysis given at the end of the report shows that it yields gasoline 

and naphtha (fractions distilled below 200° C.), about 29 per cent; 

kerosene (fractions distilled between 200° and 275° C.), about 

15 per cent; gas, lubricating and fuel oils, about 66 per cent.
50 OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO. 

O'BRIEN SPRINGS ANTICLINE.

Along the south border of the Table Hills the basal Mesaverde 

rocks and the sandstone bed about 1,500 feet below the top of the 

Steele shale dip to the north at angles that average about 40°. This 

northward dip represents the north flank of an upfold, the O'Brien 

Springs anticline, whose south flank is to be found in the same beds 

dipping southward in the northern part of T. 24 N., R. 86 W. The 

intervening .area is completely covered by dune sand, hence the 

extent of the fold and the configuration of its crest line are uncertain. 

The dip of the rocks on the south flank changes abruptly to a southeasterly and easterly direction in the northwestern part of T. 24 N., 

R. 86 W. In the northern part of T. 24 N., R. 87 W., the bedrock is 

concealed by dune sand, and the nature of the westward extension of 

the anticlinal fold into this area is therefore very obscure. Whether 

or not the anticline rises toward the west and flattens out or whether 

it becomes more closely folded and carries a local "high" or dome 

is obviously uncertain. The configuration of the anticline as represented by contours on the map is based entirely on the extrapolation 

of dips. ' f

To the writers, it seems that the change in the strike and dip of 

the rocks along the margin of the Haystack Hills suggests a flattening 

of the fold in its westward course, and that in T. 24 N., R. 87 W., it 

probably merges with the general eastward dip along this flank of 

the Separation Flats anticline, which is on the main axis of the Rawlins uplift. It is recognized, however, that the information afforded 

by the rim rocks is altogether too meager and that they are too distant from the apparent crest of the fold to indicate its configuration. 

For this reason the contours for this locality on the map are based 

on inference only. It is altogether possible, however, that a local

dome that would be favorable for the accumulation of oil and gas 

may occur somewhere in this sand-covered area. The search* for a 

possible trapped body of oil or gas in this area must be made blindly, 

inasmuch as its location along the general axis.of the fold can not be 

predicted. For this reason whatever information can be obtained 

from every well drilled in this vicinity should be recorded.

In the hope that somewhere along the concealed crest in Us. 86 

and 87 W. it might be found that the eastward pitch is arrested or a 

local "high" developed, the Kentucky-Wyoming Oil Co. drilled a 

well in sec. 2, T. 24 N., R. 87 W., to reach the G. P. sand. This well, 

started in the fall of 1920, was drilled to a depth of 3,390 feet. (See 

log G, PI. VIII.) The horizon of the G. P. sand was probably reached 

at about 1,675 feet, but no showings of oil or gas were encountered 

until the Wall Creek was reached at 3,140 feet. The showing here 

was gas, estimated at more than 1,000,000 cubic feet daily. Early 

in 1922 oil was encountered at 3,620 feet, in quantity considered large
SHERRARD DOME. 51

enough to supply fuel for further drilling in this locality. The gas 

was cased off, and the company planned to drill deeper and test the 

Muddy sand.

The Shell Co. of California completed an assessment hole in the SE. -J 

sec. 1, T. 24 N., R. 87 W., during the winter of 1921-22.

A well was started in sec. 5, T, 24 N., R. 87 W., by the Wyomass 

Oil Co. Drilling troubles were encountered at shallow depths, and 

the well was abandoned. A second effort was then made in sec. 6, 

and a hole with 15-inch casing carried to 508 feet to fulfill validating 

requirements. It is reported that the company expects to drill this 

well deeper as soon as economic conditions become favorable.

A location has been made in sec. 4, T. 24 N., R. 86 W., by the 

Matador Petroleum Co., and another in sec. 5 of the same township 

by the Washoming Oil Co. To the writers these two locations seem 

to be more favorably situated than any of those to the west.

SHERRARD DOME.

Beginning in-sec. 33, T. 26 N., R. 89 W., the Mesaverde formation, 

dipping about 40° W., swings in a broad arc southward across the 

west half of T. 25 N., R. 89 W., and then southeastward as far as 

sec. 11, T. 24 N., R. 89 W. This arc of the Mesaverde marks the west 

flank of a broad fold known as the Sherrard dome, for which the available field evidence is extremely meager. Its southeast flank is indicated by a series of dip readings, averaging about 5°, on bedding planes 

in the St.eele shale, which, crops out in a narrow belt across sees. 21 

27, and 34, T. 25 N., R. 88 W. The northeast flank is roughly 

marked by the extension of the synclinal axis indicated by the change 

in strike of the Steele shale in sec. 21, T. 25. N., R. 88 W. The southward extent of the dome is presumably marked by the sharply 

westward-pitching fold indicated by the Steele and Mesaverde outcrops in sees. 10, 11, and 12, T. 24 N., R. 89 W., and its north end 

is in like manner indicated by the sharp bend in the Mesaverde outcrop 

in sees. 35 and 36, T. 26 N., R. 89 W. The great area, about 40 

square miles, thus outlined as being occupied by the Sherrard dome 

is practically all covered by alluvial wash and wind-blown sand, 

except for a few square miles at the north end, and it is therefore 

impossible to determine the configuration of the dome or even the 

location of .its axis. Some geologists consider the evidence so meager 

that they doubt the very presence of a fold of any consequence. The 

contours on the map (PI. I) drawn for this area are almost all inferred, 

.but they show the dome elongated in a N. 35° W. direction. From 

these contours it would seem probable that the Wall Creek and other 

Frontier sands should lie within 2,000 feet of the surface throughout 

a large area.
52 OIL AND GAS, LOST SOLDIEE-FEKRIS DISTRICT, WYO.

The Kasoming Oil Co. drilled three unsuccessful holes on the 

Sherrard dome. The first was in the southwest corner of the NE. £ 

sec. 11, T. 25 N., R. 89 W., and reached the Wall Creek sand at 

1,790 feet. No information was obtained as to its findings. The 

second, in the southwest corner of the SE. £ sec. 2, T. 25 N., R. 89 W.,. 

was abandoned at a shallow depth because the hole became crooked 

and the tools were lost. The rig was skidded a short distance, and 

the third hole started. A slight showing of oil was encountered at 

1,806 feet, and the thick sandstones of the Frontier, without showings 

of either oil or gas, were found at 1,850 feet. (See log H, PI. VIII.) 

Drilling, according to the log, was continued almost exclusively in 

these sands to 2,097 feet and, at that depth, the hole filled with water. 

The hole was abandoned in the summer of 1921.

The writers do not believe that the Sherrard dome has been adequately tested by the wells drilled. At the same time it is obvious, 

from the lack of structural information, that more favorable locations 

for further testing can not be suggested, and that additional prospecting must proceed blindly and be based on the subsurface structural information obtained in drilling. By carefully determining the 

relative altitude of key beds, such as the Wall Creek sand of the 

Frontier formation, as encountered in different holes, it should be 

possible after 'drilling a few holes to locate the crest of the dome 

rather accurately. This determined, the possible productivity of the 

dome could be soon ascertained. The basal conglomerate of the 

Cloverly and at least the deeper Sundance sands should be tested 

before the dome is condemned.

SEPARATION FLATS ANTICLINE.

Early in the search for geologically favorable places for drilling 

test weUs the area north of the Bell Springs fault, on Separation Flats, 

was found to possess some of the essential features. The Mesaverde 

escarpment to the west, with its rocks dipping strongly westward, contained all the essentials for the west flank of an anticline. No complementary feature to the east is to be found nearer than the Table and 

Haystack hills, in which the eastward dip of the rocks is gentle. 

The strong dips on the west and gentle dips on the east would appear 

to indicate that the crest of the fold, which is the less highly developed 

north end of the major Rawlins uplift, is nearer the west side.

As the rocks in sees. 35 and 36, T. 24 N., R. 88 W., southeast of the 

northeast end of the Beh1 Springs fault, dip eastward, it would seem 

very probable that the rocks northwest of the fault dip in the same 

direction, although more gently. From this it would also seem 

probable that the crest of the fold lies somewhere between T. 24 N., ' 

R. 87 W., and the Mesaverde escarpment to the west. Its probable
SEPARATION FLATS ANTICLINE. 53

general position is indicated by an exposure of Niobrara shale in and 

around sec. 19, T. 23 N., R. 88 W., but its direction across T. 24 N., 

R. 88 W., over which alluvium and dune sand form a thick mantle, 

is impossible to determine, from an examination of the surface. The 

transverse downfold indicated in the rocks in sees. 11 and 12, T. 24 N., 

R. 89 W., would appear to indicate that a shallow syncline crosses 

the northern part of T. 24 N., R. 88 W., and marks the extent of the 

Separation Flats anticline in this direction and separates it from the 

Sherrard dome.

In an effort to find oil in this fold four wells have been drilled, none 

of which encountered encouraging evidence. The Texas Co.'s well 

in the southwest corner of sec. 8, T. 23 N., R. 88 W., found the Wall 

Creek sand at a depth of 1,265 feet and the Muddy sand at 2,371 feet. 

The well was abandoned in February, 1920, at a depth of 2,445 feet,, 

before reaching the conglomerate of the Cleverly.

The well 2 miles to the north, in the SE. £ sec. 31, T. 24 N., R. 88 

W., started by the New York Oil Co. and completed by the Midwest 

Refining Co., encountered the Wall Creek sand at 975 feet and the 

Muddy at 2,165 feet. No encouraging showings of oil or gas were 

found, and the well was abandoned at a depth of 2,240 feet. (See 

log I, PI. VIII.) From the depth of the Muddy sand it is clear that 

beneath the alluvium of this vicinity the Niobrara shale is the outcropping formation.

About 3 miles to the northeast, in the SW. i sec. 16, T. 24 N., R. 

88 W., the Midwest Refining Co. drilled another hole to a depth of 

3,055 feet and then abandoned it. The log of the hole, to which the 

writers had access, indicated that the Wall Creek sand was reached 

at about 2,180 feet but gave no encouraging showings. A little gas 

was found in shale at 1,040 feet.

The same company also drilled a well 2 miles farther north in the 

NE. i sec. 9, Ti 24 N., R. 88 W., in which a little gas was encountered 

in shale at 1,370 feet. The log was very indefinite, and the writersmade no attempt to hazard an interpretation. The drill went to a 

depth of 2,530 feet before the hole was abandoned, and it was reported 

that shale only was penetrated.

These rather widely scattered test wells have discouraged additional 

drilling, but it must be realized that the linear distribution of these 

wells was not the most helpful in locating the crest of the fold. Without surface rock exposures to indicate the configuration of the fold 

it is impossible to suggest more favorable places at which to drill. In 

view of the possibility that there may be in the area points structurally higher than those where wells have been drilled, the writers, 

believe that the anticline has not been adequately tested.
OIL AND GAS, LOST SOLDIER-FERRIS DISTRICT, WYO.

PETROLEUM ANALYSES. 

The following analyses were made in the Bureau of Mines:

Analyses of petroleum from the Lost Soldier-Ferris district, Wyo.

[Distillation in Bureau of Mines Hempel flask.] 

Lost Soldier field.

Temperature

50 to 75.........

75 to 100.. ...... 

100 to 125.......

125 to 150....... 

150 to 175.......

175 to 200.......

200 to 225.......

225 to 250.......

250 to 275.......

275 to 300.......

Laboratory No. 0378. Specific gravity at 

15° C., 0.867 (31.5° Baum6). Amount 

distilled. 200 cubic centimeters. First 

drop, 51 6 C. Sulphur, 0.15 per cent.

Air distillation, with 

fractionating column (barometer 

754 mm.).

Fractions 

(per 

cent by volume).

0.7 

2.5

3

Q

3.9 

4.0 

3.2 

4.7 

5.9 

6.6

Total 

per 

cent 

(by volume).

0.7 

3.2 

7.0

10.9 

14.9 

18.1 

22.8 

28.7 

35.3

Specific 

gravity.

JO. 740 

.772

.798 

.815 

.828 

.842 

.851 

.856

Vacuum distillation, 

without column 

(pressure 40 mm.).

Fractions 

(per 

cent by volume).

""i.'i"

7.0 

9.1

9.2

8.2

7.7

Total 

per 

cent 

(by volume).

"se.Y

43.7 

52.8 

62.0 

70.2 

77.9

Specific 

gravity.

"6"859" 

.859 

.858 

.867 

.877 

.881

Laboratory No. 0375. Specific gravity at 

15° C., 0.868 (31.3° Baum6). Amount 

distilled, 300 cubic centimeters. First 

drop, 51° C. Sulphur, 0.34 per cent.

Air distillation, with 

fractionating column (barometer 

758mm.).

Fractions 

(Per 

cent by volume).

f 1.0

\ 2.7 

4.7

4.0 

4.2 

3.9 

5.0 

5.8 

8.3

Total 

per 

cent 

(by volume).

1.0 

3.7 

8.4

12.4 

16.6 

20.5 

25.5 

31.3 

39.6

Specific 

gravity.

JO. 731

.779

.802 

.820 

.830 

.842 

.852 

.857

Vacuum distillation, 

without column 

(pressure 40 mm.).

Fractions 

(per 

cent by volume).

""i.'s"

7.2 

10.8 

8.8 

7.8 

5.3

Total 

per 

cent 

(by volume).

"ii.T

48.6 

59.4 

68.2 

76.0 

81.3

Specific

ity.

" 'o.'sei

.860 

.858 

.872 

.882 

.893

Ferris field.

Temperature 

(°C.).

Up to 50.......

50 to 75.. .......

75 to 100........

100 to 125.......

125 to 150.......

150 to 175.......

175 to 200.......

200 to 225.......

225 to 250.......

250 to 275.......

275 to 300.......

Laboratory No. 0382. Specific gravity at 

15° C., 0.826 (39.5° Baum6). Amount

distilled, 200 cubic centimeters. First

drop, 51 8 C. Sulphur, 0.12 per cent.

Air distillation, with 

fractionating column (barometer 

765 mm.).

Fractions 

(per

cent 

by volume).

2.1

2.9

7.0

7.2

6.0

4.9

3.5

3.7

4.7

5.0

Total

per 

cent

(by volume).

2.1

5.0

12.0

10 9

25.2

30.1

33.6

37.3

42.0

47.0

Specific

gravity.

0.668

.678

.719

.742

.760

.779

.795

.810

.820

.829

Vacuum distillation, 

without column 

(pressure 40 mm.).

Fractions 

(per

cent 

by volume).

2.0 ? i

6.5

7.4 f; i

5.8

Total

per 

cent

(by volume).

49.0

52.1

58.6

66.0

71.3

77.1

Specific

gravity.

0.836

.844

.848

.863

.875

.883

Laboratory No. 0376. Specific gravity at 

15° C., 0.828 (39.3° Baume"). Amount

distilled, 300 cubic centimeters. First

drop, 24° C. Sulphur, 0.20 per cent.

Air distillation, with 

fractionating column (barometer 

758 mm.).

Fractions 

(per

cent 

by volume).

3.8

3.1

5.6

6.6

5.1

4.4

4.1

3.9

4.7

5.3

Total

per 

cent

(by 

volume).

3.8

6.9

12.5

19.1

24.2

28.6

32.7

36.6

41.3

46.6

Specific

gravity.

0.631

.671

.713

.741

.760

.778

.793

.808

.818

.828

Vacuum distillation., 

without column 

(pressure 40 mm.).

Fractions 

(per

cent 

by volume).

.......

1.5

5.5

5.5

6.6

6.4

5.9

Total

per 

cent

(by volume).

.......

48.1

53.6

59.1

65.7

72.1

78.0

Specific

gravity.

.......

0.842

.841

.847

.859

.873

.885
DETERMINATIONS OF POROSITY. 55

The following analysis was made in the Vernon Refinery laboratories of the General Petroleum Corporation:

Analysis of crude oil from well No. 1, sec. 16, T. 25 N., R. 86 W. '

{Gravity at 60" F.. 38.3° Baume". M. and B. S.. trace. Cold test, below -2° F. (flowed slowly at this 

temperature). Saybolt viscosities at 80° F., 45 seconds; at 60° F., 68 seconds; at 40° F., 515 seconds; 

at 20° F., 7,500 seconds." 1000 cubic centimeters distilled in a 2000 cubic centimeter flask with modified 

Hempel tube. Each fraction 2 per cent.]

Fraction.

1

2

3

4

5

6

7

8

9

10

11

12

13

Temperature (*F.).

96

126

168

194

218

. 232

248 '

273

283

300

316

338

356

Gravity 

at 60" F.

93.4

92.6

79.5

69.4

64.0

61.0

59.1

57.2

55.7

54.3

52.9

51.3

49.6

Fraction.

14

15

16

17

18

19

20

21

22

23

24

25

Temperature (° F.).

375

400

420

445

460

475

492

514

532

552

562

574

Gravity 

at 60° F.

47.8

46 3

44.9

43.3

42.5

41.7

40.8

39.9

39.1

38.7

38.0

37.5

a This is probably higher than the true viscosity of the oil owing to the formation of paraffin crystals 

which clogged the viscosimeter.

DETERMINATIONS OF POROSITY.

The porosity of a number of sand samples from the Lost Soldier 

district has been determined by A. F. Melcher. The method employed 23 determines the volume of the voids in the sample but does 

not show what percentage of these voids would be filled by oil or 

gas. The close relation between porosity and productivity makes 

it appear probable that in a sand that occurs in an oil field most of 

these voids are actually filled by oil. The determinations are as 

follows:

Wall Creek sand (top member of Frontier): . (per cent). 

Bair well No. 32, sec 10, T. 26 N., R. 90 W.......... 20. 1

Outcrop, sec. 23, T. 27 N., R. 89 W_......._:....... 19. 9

Muddy sand:

Outcrop, sec. 12, T. 27 N., R. 89 W................. 17. 9

Outcrop, sec. 33, T. 27 N., R. 88 W._._............. 12. 5

Well on Wertz dome, sec. 7, T. 26 N., R. 89 W....___. 11. 4

*> Melcher, A. F., Determination of pore space of oil and gas sands: Am. Inst. Min. and Met. Eng. 

Trans., vol. 65, pp. 469-497,1921.

INDEX.

Page. 

Access to the district..........._...._ 5-6

Acknowledgments for aid.................. 5

Amsden formation, occurrence of._____ 13 

Analyses of petroleum____________ 54-55

Bonine, C. A., acknowledgment to. _...... 5

Bunker Hill dome, description of._____ 39-40

'Cambrian quartzitc, occurrence of.-...-- _ 12

 Carlile shale, occurrence of...._______ 23-24

 Cloverly formation, occurrence of..____ 17-19

 Cretaceous rocks, occurrence of_______ 16-28

Dips, steep, effects of........................ 32-33

Discovery of oil fields in the district....__ 1.8

Distribution, stratigraphic, of oil and gas. _ 28-29

Drainage of the district-______...._ 7

Examinations, previous.....________ 4-5

Ferris dome, drilling on.......___...._ 45

geology of......___._________ 43-44

oil produced from....._______ 45-46

analyses of....._____._.... 54

Ferris Mountains, plate showing. _____ 8 

Folds and uplifts of the district..--....-_._. 30-31

Field work, record of._.._....__.... 3-4

Frontier formation, occurrence of, and oil

and gas in..__________ 21-23 

walls of, plates showing......____.. 8

 G. P. "dome," drilling on............._ 46,47-48

geology of.... __.......______ 46-49

oil produced from....._________ 49

analysis of......._...____.__ 55

O. P. oil field, looking west, plate showing.. 27 

Geography of the district..... ........ 5-9

Geology of the district....................... 9-28

summary of............. ... 1-3

Jurassic and Cretaceous (?) rocks, occurrence

of............................... 16-17

TCrampert, E. W., acknowledgment to__.. 5

Lewis shale, fossils in......___.___... 28

occurrence of.._____....______ 28

Location of the district. _____..____ 5-6

Logs, graphic, of oil wells, plate showing__ 34

Lost Soldier dome, character of oil in__ 35-36,54

drilling in............................... 34-35

geology of............................... 33-34

map of...._......____._____ 34

production from..... .. ____ 36

sands, deep, possibility of oil in.......... 35

Lost Soldier Ferris district, map of......... 4

Madison limestone, occurrence of......i__ 12-13

Page.

Mahoney domes, drilling on__. _____ 41-43 

geology of.....___....________ 40-41

Markets for oil and gas...._________ 8-9

Mesaverde formation, escarpments of, plates

showing....__.... 26

nature and occurrence of........ ___.. 26-28

section of, plate showing...........__ 27

Mississippian rocks, occurrence of.. ____ 12-13 

Mowry shale, occurrence of......__._.. 20-21

Niobrara shale, occurrence of...__ ..... 23-24 

O'Brien Springs anticline, description of__ 50-51

Pennsylvanian rocks, occurrence of . 13-14 

Pipelines, laying of............ 8,9

Porosity of sands, determinations of...._.. 55

Pre-Cambrian rocks of the district.... _.... 12

Purpose of examining the district....... 1

Red beds, occurrence of......__.......... 14-15

Roads of the district.............. .. 8

Sand, source and influence of...... 7

Sand dunes, plate showing.... 8

Section, generalized stratigraphic, in the

district..............- . ... 9-11

Separation Flats anticline, description of. 52-53

drilling on......._..-.......--.... 53

Shale, bedrock, plate showing.._.. ..... 8

Sherrard dome, description of......... 51

drilling on.............................. 52

Stanton, T. W., fossils determined by....... 21,26

Steele shale, fossils in.............. ...... 25-26

occurrence of......._....._...... 24-25

Strata, oil-producing, of Wyoming......... 9,12-28

Stratigraphy of the district... 9-29 

Structure of the district..................... 30-33

methods used in representing..-. . . 31-32 

Summary of the geology........... -. 1-3

Table Hills, plate showing.................. 26

Tensleep sandstone, occurrence of... 13-14 

in Whisky Gap, plates showing...... 8

Thermopolis shale, occurrence of......... 19-20

Topography of the district............. 6-7

Uplifts and folds of the district.............. 30-31

Vegetation of the district......... ..... 7

Wall Creek sand, structure of, maps showing. 4,34 

Water supply of the district....... 7

Wells, graphic logs of, plate showing......... 34

Wertz "dome," drilling on........_....... 37-38

eastward extension of.... .... 39

geology of.....------..---.-...-.--..-. 36-37

Whisky Gap, plate showing........ .. 8

57

O