The fossil fields of Wyoming; reports by members of the Union Pacific expedition

NY, PACIFIC ey

graveslt

| WYOMING |

iF “Ohh aa

The Fossil
Fields of
W yoming

Reports by Members
of the

Union Pacific Expedition

ISSUED BY
PASSENGER DEPARTMENT,
UNION PACIFIC RAILROAD COMPANY,
OMAHA, NEBRASKA.

ff

Copyrighted for
Union Paciric RaILrroaD CoMPANY
by
IDs Is IOV Ce JE LNs
Omaha, Neb.,
1900. ,

Was. C087, 208L |
wa |

FOREWORD

The fossil fields of Wyoming are widely known in this
country among the students of paleontology, and their peculiar
value to scientists has been established for many years. The
general characteristics of this region, its contour and formation,
fauna and flora, and the particulars of the different strata found
there have been given the public by many men eminent in their
profession. Professor Marsh of Yale many years ago recorded
the results of his researches, and F. V. Hayden, Clarence King
of the U. S. Geological Survey, Arnold Hague, J. J. Stevenson,
Marvin and Endlich, and others, have described the country
in detail.

In July, 1899, the passenger department of the Union
Pacific Railroad sought to revive interest in the further explora-
tion of this wonderful field, and to that end invited a number
of scientific men to visit that part of Wyoming and make per-
sonal investigation of the field. They went as guests of the
Union Pacific and were escorted by an official of the company.

Several of these gentlemen recorded their impressions and
experiences, and in some instances embodied in their review a
a critical and comprehensive account of their findings which
form a valuable contribution to science; and it has been thought
proper to make these papers public on account of their intrinsic
worth and interest.

At the time this expedition, or excursion, was made it
was given full prominence in elaborate newspaper articles
and in magazine reviews, and this seemed then to meet all re-
quirements. But, more recently, inquiries have constantly been
received asking for fuller and more detailed information if it
was attainable. It is to meet this demand that these personal
statements by members of the excursion are published.

Passenger Department

UNION PACIFIC RAILROAD,
Omaha, 1909.

BLBL Ul “OAAA ‘OWOD }B PUNO} SNinesoBays jo UO!}EIO}sSAYy

SEORY OF THE DISCOVERIES

HE first great fossil expedition in Wyoming was
conducted in the summer of 1870 in what is now
known as the Bridger Basin, near Fort Bridger.
An immense amount of material was found at

that time by Professor O. C. Marsh and his expedition. He

obtained concessions from the Government and had an escort
of two companies of United States soldiers. The material

particularly searched for and found at that time was the bones
of the early horses, the ancestors of the modern horse.

In the lowest horizon of the Tertiary, at the foot of the
Wasatch Mountains, was found a three and a four-toed horse.
Above, in a later age, were found the bones of the toes draw-
ing up, leaving one central toe. Many examples of this were
found; and, as the Professor worked toward the upper Pliocene
Tertiary, he found the horse as he is to-day with the exception
of the size. The earliest of the horses, the three and four toed,
were about as large as a fox. Several thousand feet higher in
the upper Tertiary the horse had taken his form of to-day, but
the size was not much increased; he was still small, a little larger
than a fox. In searching for these bones of horses in which
Professor Marsh was paiticularly interested, the bones of many
other mammals were found, particularly camels, cats, dogs, bea-
vers, and deer. These bones were all carefully taken up and
shipped to the Yale Museum from Carter Station, on the Union
Pacific. Several similar expeditions were sent into this field in
the years from 1870 to 1877, and many wonderful discoveries
were made. Still other expeditions going into this field in later

THE FOSSIL FIELDS OF WYOMING

times found something new to science; and | consider the field
still exceedingly rich in this material, to anyone who wishes
to investigate such things.

On March 7, 1877, I found, one and one-half miles
from Como Station, on the Union Pacific, the bones of some
dinosaurs. These were the first found in the Rocky Moun-
tain region. 1 commenced work on this material on the date of
discovery and shipped one ton of these bones to Professor Marsh
in the month of June the same year. Then Professor
Marsh sent out Dr. S. W. Williston, now in the University of
Chicago, Chicago, Illinois, to look after the work for a short time.
Dr. Williston and myself worked in this quarry about one year
and took a good portion of three skeletons out of it. About
this time Professor E. D. Cope of Pennsylvania put a party into
the field and there was much competition between the
Cope and Marsh parties for several years. Many valuable
discoveries and a great addition to scientific information resulted.
This material, collected from 1877 to 1888, was divided
between the Smithsonian Institution, at Washington, and Yale
Museum. Professor Cope’s collection was shipped to Phila-
delphia where he investigated and made some valuable restora-
tions. After his death the collection was sold to the American
Museum, Natural History, New York, and is among its
mort valuable possessions to-day. Since 1888 the American
Museum, the Carnegie Institute at Pittsburg, the Field Colum-
bian Museum at Chicago, Harvard University, and Princeton
University have had parties in this region nearly every year
and an immense amount of fossils has been discovered and
shipped to the different institutions.

Wyoming University commenced in 1895 to collect material
for a museum. ‘This has been carried on to the present time,

—5—=

SLORY -OF THE DISCOVERIES

and we now have in this collection about eighty tons of fossil
bones, mostly of the reptilian kingdom, but also a large
amount of Tertiary or mammalian bones. ‘These are being
worked up and put on exhibition as fast as possible.

The field is exceedingly rich, and, to me, after nearly forty
years’ experience in this work, it seems just as good as before
it had ever been touched. No party that makes a thorough
investigation in one summer ever goes away empty-handed ;
usually some exceedingly rare and rich fossils are found.
There is no square on the earth as rich as Wyoming in its
fossil forms of ancient life. From the Permian, at the close
of the Paleozoic, to modern annals, nearly all the life that has
ever lived upon the earth can be found within the limits of
this State. Of course it takes, first, knowledge and, second,
energy to find and bring these things to light; but that is all
that is necessary to equip the fossil hunter for successful work
in Wyoming.

Welt REED
Curator, Museum, University of Wyoming,
Laramie, Wyo.

OBSERVATIONS ON THE EXPEDIVION

In response to an invitation by the Union Pacific Railroad
Company, a large party of scientists arrived in Laramie, one of
the principal cities of Wyoming, on the 19th of July. The
writer was at once impressed with the purity of the atmosphere
of this country and the sparkling water trickling down the
streets of this beautiful city, coming from a large spring two
miles away. To fully appreciate its purity and deliciousness
one must take a draught of it; no description will do it justice.
Two days after arriving in Laramie, the expedition moved to
the west, making a circle, the terminus of the trip to be the
Grand Canon of the Platte River. We passed over excellent
collecting grounds both in plant and invertebrate fossils, and on
the eighth day of the trip we arrived at Aurora, the historic
dinosaur field, where Professor Marsh of Yale, more than
thirty years ago, discovered the bones of these immense lizards
which are fully described in the sixteenth annual report of the
Geological Survey. Here quite a number of specimens were
found, and after remaining a day and two nights, we started
for Freezeout Mountains, going by way of Medicine Bow,
a small station on the Union Pacific Railroad. In these
mountains the expedition was on virgin dinosaur fields and, so
far as I know, every member of the party found and shipped
some specimens of these bones. ‘The writer, in connection with
Prof. S. B. Brown of West Virginia University, found five
vertebrae, two large femora and quite a number of large pieces
of other bones of these animals. In this region we saw the
bones that are being excavated by the American Museum
people, also the Field Columbian, the Wyoming University
and Kansas University Museums.

—sg—

OBSERVATIONS ON THE EXPEDITION

The hundreds of square miles of these beds containing
thousands of tons of the bones of these huge vertebrates, some of
which are exposed by erosion each year, impresses one with
the vastness of the burying ground over which we were traveling
and the history of its formation and inhabitants while it was a
low marshy plain. These bones are imbedded in a pale
bluish-green stratum of clay varying in thickness from twenty
to fifty feet. This stratum is easily found and recognized,
being immediately above the shale overlying the Triassic red
sandstones, under which is a layer where the belemnites are
found very abundantly. Above the dinosaur stratum is a thick
layer of sandstone, and boulders from this often tumble down
dragging the bones among the talus, often making it difficult to
determine the exact point from which the bones came.

From our camp at Freezeout Mountains by three marches
we arrived at the Grand Canon of the Platte. Here the Platte
River has cut a channel with almost vertical sides a thousand
feet deep, through the strata for a distance of nine miles. Owing
to the arduous task of entering the canon, at many places this
being impossible, the study of the exposed strata at close range,
becomes somewhat difficult. The writer, in company with
Lieutenant Murphy of Wyoming University, entered the canon
and drank from the rushing river. None of our company were
daring enough to attempt to go through the canon, although we
were told that only one man had ever succeeded who attempted
it. On approaching the canon it was seen that we were on a
rolling plain, indented here and there with small streams that
had made rather deep channels for this country. However,
I am sure it would never occur to a stranger that only two or three
hundred yards in front of him was a chasm a thousand feet deep.
Almost instantly you perceive there is a great canon in front

—j—

Right hind leg of largest Dinosaurus known, mounted in the museum, University of
Wyoming. Found five miles south of Medicine Bow on Union Pacific Railroad

OBSERVATIONS ON THE EXPEDITION

where a moment ago you thought it was a perfect plain. Then
you undertake to enter it through a ravine and travel many times
the distance it was supposed to be, and of a sudden you find
yourself standing on an immense strata of rock, a step more
would land you six or seven hundred feet below in a stream
which rushes madly, as it were, past the boulders that have
fallen from the cliffs. If one has imagined that he would like
to go through the canon his slightest wish quickly leaves him on
seeing the danger of such an undertaking. The most sublime
sight I ever beheld was to stand on the edge of this canon and
see the tilted strata, the Archean to the left and below, and look
to the right and see the great number of strata through the series
to the characteristic red beds of the Triassic and above these
the Jurassic. The scene impresses one in a way that words
meagerly describe, but the feeling comes that here is an epitome
of Nature’s records inviting one to read the history of these for-
mations, see the principles of structural geology here unfolded,
and conceive the great length of time necessary for their con-
summation.

The noted Fremont fault is about three miles north of the
canon. Here the carboniferous lime and sandstones are
faulted and lying on the Jurassic, apparently, almost conform-
able. Here are five hot springs, the temperature of the largest
being 140 degrees. The entire route through Wyoming
afforded a most excellent opportunity for studying geology.
The great amount of tilted and eroded strata, and the sparse
vegetation, enabled one often to follow for miles, with greatest
ease, a single formation, or to cross a great many different ones
in traveling only a short distance.

In conclusion [ wish to say ! am very grateful to our leader,
Prof. Wilbur C. Knight, for his able and efficient service
and his many valuable suggestions, also to the Union Pacific
Railroad Company for its many courtesies.

J: A YATES,
Professor of Natural Sciences, Ottawa University,
Ottawa, Kansas.

—l] —.

ere

Front limb of Diplodocus in the museum, University of Wyoming, Laramie, Wyo.
Found in Freezeout Hills, fourteen miles north of Medicine Bow, on
Union Pacific Railroad

PRACTICAL VALUE OF THE
EXCURSION

Learning that the Union Pacific is to publish some of the
results of the recent Fossil Field Expedition, so admirably
planned and so successfully carried out by the railroad and
Prof. W. C. Knight of the University of Wyoming, I hasten to
add my testimony to its benefits. They may be briefly
enumerated as follows:

1. It enlarged greatly the stock of knowledge of every
geologist enlisted, and of that sort best calculated to improve
his teaching capacity. It substituted clear typical object
lessons for the meager illustrations and halting descriptions of
textbooks. Even those familiar with typical examples in the east-
em part of our country were greatly impressed with the great
advantage of the absence of vegetation and cleamess of
atmosphere in Wyoming. Views were more comprehensive and
details more distinctly exhibited. This was true particularly
of folds, faults, wind work and stream work, stratification and
concretions. It afforded opportunities for excellent acquaint-
ance with most interesting formations and fossils not accessible
in the east.

The erosion forms, the work of untold ages on the granite
axis of the continent; the carboniferous rocks without coal;
the glowing red beds; the Jurassic, with its various horizons,
including probably the oldest great fresh water lakes, with
their huge dinosaurs; the stretches of Cretaceous with its sand-
stone ridges and mesas, its gumbo plains and slopes, its chalk
cliffs glaring across the waste, its swarms of fossil shells, its
gigantic globular concretions, its coal beds with fossil palms
and deciduous trees; the Tertiary lake beds, with their mon-

peoiley f10B4 UOIUA) $0 YOU AWenb B Ul puNnoy sauog |paay UOpOUURdeg

PRACTICAL VALUE OF THE EXCURSION

strous mammalian bones, remnants of Nature's efforts in pre-
paring the various beasts of the present time; the gravel-spread
and boulder-dotted terraces of the Pleistocene age, records of the
former floods which worked so faithfully to humble the pride of
the rising Rockies, and convey their grandeur to beautify and
enrich the plains of the Mississippi—all these are now vivid
realities in the minds of all who rode over them and worked
about them with this expedition.

2. It will furnish substantial contributions to science. It
is not yet time to sum up results in this line. Months and _per-
haps years may pass before we know what new species have
been found, what conclusions are reached by many minds
brought face to face with that wonderful region. It was not an
unknown region. Many bright minds had already traversed it.
Yet some new discoveries may be, at least, hinted. Numer-
ous deciduous leaves were found mixed with abundant marine
forms in the Fox Hills beds. A considerable fauna of fresh-
water invertebrates was found in the dinosaur beds of the Jurassic.
This will no doubt be fully presented by those more closely
identified with the discovery. The opinion that the Fox Hills
group is but a sandy local development of the Fort Pierre will
be strengthened by the work of the expedition, and furthermore
it may appear that the Laramie is but a local fresh water stage
of the same.

Several additional new features have been revealed in the
dinosaur bones unearthed by this expedition.

3. It has and will promote popular interest in science and
education. ‘Thisis not only by the public press and the pictures
and fossils scattered by the members of the expedition throughout
the country, but by the individual articles and lectures and by
the proposed illustrated history.

aSuBY MOG aUld|palA] }O UO!}BUJLUIA} BY} S| PUB YBIY 182} QOO'LL
}noqe s| uje}unow siy| ‘a|/WieBe> PUB SUI|MeYy U@eMjeq S}U|Od AuBW }e UBes ag UBD YO|YM ‘UlEJUNO|| y/9

PRACTICAL VALUE OF THE EXCURSION

It calls fresh attention to the conclusions of geology concern-
ing the building of the earth and the development of life-forms.
It reveals to many a new world of the imagination. Science
has swept into oblivion the whole brood of mythological
monsters, centaurs, griffons, chimeras and dragons, that once
delighted the lovers of the terrible and strange, but now it is sub-
stituting the monsters of geological lore. It arouses new interest in

“The fairy tales of Science and the long result of Time.”

It will stimulate a more healthy interest in science for its own
sake.

4. Let us hope that this expedition may arouse such lasting
interest in scientists and the patrons of public museums in the
wonders of the West that it may be but the first of a long series
of similar vacation excursions which may prove of mutual
advantage to all engaging in them and to the public at large.

Es ODD;
Professor of Geology and Mineralogy,
University of South Dakota.

ITS WORTH TO Tak
STUDENT

It has become a proverb that for a geologist there are three
requisites for success: The first is travel, the second is travel and
the third is travel.

The Union Pacific Railroad Company was thus contribut-
ing to the success of a large number of geologists, when it
made accessible to them that open book on geology, the Wyo-
ming plains and mountains; and those who were so fortunate
as to be able to accept the invitation gained results the value of
which it would be hard to estimate.

All forms of geological phenomena were so well presented in
Wyoming as to be well nigh diagrammatic and it would be
difficult to say in which department of the science the greatest
interest was felt and the greatest profit attained.

Students of structural geology, who were acquainted with
Appalachian and Alpine mountain architecture alone, beheld
such monoclines, synclines and anticlines as they had never seen
before.

Students of physiographic geology observed peneplanation
on a world-wide scale, and had presented to their view splendid
examples of erosion that varied from the cuttings of rivulets
through non-resistant regolith to the powerful carving of the
Grand Platte through tenacious Mesozoic sandstones and lime-
stones, through Paleozoic rocks of similar character and
through Archean quartzites and granite.

The student of economic geology had opportunity to be-
come acquainted with Wyoming coal deposits, gypsum beds,
various building stones, railroad ballast and road material, and

—=19-—

ITS WORTH TO THE STUDENT

saw possible sources of carbonate of soda, magnesium sulphate
and asphalt for commercial use.

An excellent chance was afforded petrographers for collect-
ing sedimentary rocks, representing geological periods all the
way from Tertiary to Ordovician, and crystallines from the Pale-
ozoic and Archean.

The region traversed was not especially rich in mineral
wealth, yet there was opportunity to collect fine quartz of
many varieties, calcites and aragonites, graphite, gypsum and
various iron-bearing minerals. ;

Invertebrate paleontologists fared even better than the
petrographers and mineralogists and the variety and quantity of
their collections were among the chief rewards of the expedition.

The chief interest of the general public in the expedition
was in the vertebrate remains that were known to exist in the
various geological horizons. “These the excursionists hoped to
see exhibited in position in bed rock and to have opportunity
to carry away with them to be used later for the convincing
of the incredulous.

Jurassic dinosaurs were looked for with the greatest enthusiasm
and nearly every member of the party carried home some trophy,
even though it may not have been more than a small fragment;
and some members secured desirable material. The North-
western University party sent home about two tons of specimens,
the greater part of which consisted of the spinal column, ribs
and pelvic arch of a dinosaur that is probably the form known as
ceratosaurus. It was found in the Freezeout Hills, in the
region of the Platte Canon. The same party located reptilian
remains. But the absence of plaster and other means of saving
the materials, as well as the remoteness of the region, made work
in that locality appear undesirable.

19

BLB) U! ‘PBoey op198q4 vol)
uo “OAAA ‘OWOD }B PuNOY “ULOD ‘'U@ABY May ‘Winasn a]BA Ul SNineso}UoIG $0 UO!}E10}Soy

ITS WORTH TO THE STUDENT
Great credit is due Prof. Wilbur C. Knight for his

untiring efforts and skill in conducting the expedition, and all
members of the party appreciate his work and feel under great
obligation to him.

The thought was indeed most happy which led the Union
Pacific Railroad to organize the expedition as it did.
Every member of the party returned to his work invigorated
in body, enthusiastic in spirit and furnished with an increased
fund of illustration for teaching and material for investigation.
So that every student who comes in contact with these tourists—
and they number thousands—will profit by the generosity of
the Union Pacific. Further than this some contributions to
scientific knowledge will result. Consequently the Union
Pacific Railroad is to be congratulated upon having contribu-
ted to the progresss of civilization in this regard also, and to
it is due the heartfelt thanks of others than those who were
the most immediate and evident gainers in this generous and
well planned expedition.

A. R. COOK,

Professor of Mineralogy, Northwestern University,
Evanston, Ill.

is

AN ENJOYABLE OUTING

When the Union Pacific Railroad proffered an invitation
to the geologists of various colleges and universities in the United
States to visit what are now considered the most prolific fossil
fields of the world, it rendered an undoubted service to science.
On July 19th we reached Laramie City via Denver, where we
were pleasantly quartered and on the night of our arrival were
given an enjoyable reception by the citizens of Laramie. As
outlined in the letter of invitation sent us, we were to travel by
wagon from Laramie. Prof. Wilbur C. Knight had with keen
foresight secured twenty or more farm wagons and drivers
who were well acquainted with the territory over which we
were to travel. We divided up into messes of ten, with drivers,
cooks, tents, bedding, etc., and on the morning of July 2[st,
we left Laramie, with about eighty people in the company,
there being about sixty geologists and students from colleges
in all parts of the United States: California, Minnesota,
Texas, Alabama, New York, etc. The National Museum,
Washington, D. C., was ably represented by Prof. Schuchart.
At Fox Creek, in the adjacent mountains, were found thousands
of gastropoda, mollusca and concretions, also beautiful speci-
mens of quartz in all colors; many fine amethysts were
picked up. We lingered here until Monday morning; again we
moved to the north. About noon we reached the coal fields
of Carbon County. The entire party halted and we were
soon busy collecting leaf impressions which overlay the coal to
a thickness of at least four feet; the impressions are so perfect
that the most minute markings of the leaves are as clear as the
dried leaves of the various trees would show. We next went

—

AN ENJOYABLE OUTING

into camp at Rock Creek, a most beautiful grassy valley. Rock
Creek might well be called a river, as a large volume of clear
water is constantly flewing through its channel. Beautiful
snow-capped Elk Mountain was ever to our left, and Laramie
Peak to our east. From Rock Creek camp, side trips were
made to the great chalk cliffs and the ammonite and gastropod
fields nearby. Many hundreds of pounds were collected, care-
fully packed in boxes and shipped from Rock Creek station, by
the various college representatives. “The writer was so fortu-
nate as to find a mollusk, twelve inches in diameter, showing
all the colors as bright as it could have been in the Tertiary.
After a three days’ halt at Rock Creek camp, we traveled
directly north and at the end of the day reached the great dino-
saur beds, or fields, of Wyoming, and went into camp not over
two thousand feet from where Professor Marsh, of Yale College,
discovered and successfully removed one of the largest dino-
saurs discovered in the world. Professor Knight of Wyoming
University and Professor Williston of Kansas University have
recently made some valuable finds at this place. Several of our
party secured some valuable specimens of femora and vertebra.
Professor Yates of Ottawa, Kan., University and Professor
Brown of Virginia, also Professor Charlton of Texas, were highly
successful in securing specimens for their colleges. “This section
of the Freezeout Mountains shows many wenders in the various
folds and wnconformities. [ake Como and Como Station were
nearourcamp. Alter a two days’ extremely interesting stop, we
moved northwest and, at Medicine Bow, I, through press of
other business, was reluctantly compelled to leave the party
and return to “Sunny Kansas,’ much benefited in health and

knowledge. H. L. T. SKINNER,

Ottawa, Kansas.

Peo IeYy jI0BY UOIUA, $O YOU puNnoy
‘OA AA ‘@]WUBIe > ‘BulWoAAA 4O AjisiaAlup) ‘WinesnwW ey} Ul sdk} Y ‘“SjalUuBD AjiBa 94} JO BUO JO UO}ajax%s BY]

GEOLOGY OF THE LARAMIE
PLAINS

Traveling westward along the Union Pacific Railroad, we
reach Cheyenne and find that we are 6,050 feet above the
sea. Thirty-three miles farther west, we are at Sherman, on
the summit of the Laramie Mountains, a little over 8,000
feet above sea level. “Twenty-four miles farther on, we descend
upon the Laramie Plains and are 7,149 feet above the
sea. Then, for 270 miles farther, our route over the railroad
will pass along the valleys scalloped out of the plains and undu-
lating between 7,100 and 6,740 feet, until, on descending the
valley of Green River, we are 6,077 feet above tide. For
100 miles of this distance the road traverses the well-known
Laramie Plains. The Laramie Plains are bounded on the
east and north by the Laramie Hills, on the south and west
by the Medicine Bow Mountains and their extensions. The
plains may be 25 to 40 miles wide, and, beginning near the
line of Colorado and Wyoming, they extend northwardly
for 100 miles, thence northwestwardly for 50 miles. On the
west, the Medicine Bow Range forms a prominent barrier as
far north as Elk Mountain, thence it drops off into valleys con-
tinued beyond in the Seminole, Shirley and Indian Grove
Mountains to the Grand Canon of the North Platte. These
mountains are all granitic; Elk Mountain is 11,000 feet alti-
tude. The granite of the Seminole, and similar ranges north,
is a coarse, red feldspathic and would undoubtedly afford an
excellent quarry rock.

The plains near Laramie City are from 7,100 to 7,500 feet
above the sea, but northwardly they are from 6,500 to 7,000

THE FOSSIL FIELDS OF WYOMING

feet elevation. The hills just south of Como rise 400 feet above
the plain, caused by uptilting of strata. Within ten miles north
of Medicine Bow, hills appear on the left and twenty miles
north we are in the Freezeout Mountains; a few miles farther
are the Freezeout Hills. By quaquaversal upthrusts this
region has been thrown up and tilted so as to form beautiful
anticlinals, bringing to view the Triassic and Jurassic, capped
by Dakota Cretaceous. Viewed from several miles east, the
Freezeout Mountains present an interesting panorama, the strata
toward the southeast end dipping southeast, while that south a
few miles off dips south, with the central portion very much
eroded, the whole a beautiful illustration of an anticlinal valley.
The eroded hills, formed of Jurassic beds capped by Dakota
sandstone, afford picturesque scenery near Rock Creek, Little
Medicine and the Freezeout Hills northwardly to the Seminole
Mountains. In this region are beautiful exhibitions of anticlines,
synclines, faults and erosion. The plains are mostly underlaid
by later cretaceous. The Dakota group consists chiefly of
sandstone. The Fort Benton group is chiefly clay shales with
fish scales and teeth. The Niobrara crops out in the lower hills
of the plains. The Fox Hills group consists chiefly of sandstone
and shales with some hard concretionary masses of calcareous
sandstone, often containing fossil mollusca.

The Laramie Plains are traversed by tributaries of the
North Platte, including Laramie, Rock Creek and Medicine
Bow, all swiftly flowing streams, with an abundant supply of
clear, cool water. These streams all originate in the Medicine
Bow Range. Occasional small lakes occur on the plains;
Cooper's Lake is the largest. Como is also a pretty body
of water. Some of the lakes contain valuable deposits of soda.

—26—

GEOLOGY OF THE LARAMIE PLAINS

The surface of the plains generally consists of two to three ter-
races, the higher one often flat on summit and with scant grass.
Most of the terraces are sandy and frequently are strewn with
water-worn pebbles. The valleys along the streams are wide
and often slope up gently to the terraces above. Grass abounds
on the valleys, and, with judicious irrigation, can furnish plenty
of hay and also good grazing. Most of the valleys of the tribu-
taries of both the Platte and the Laramie may be considered
as valuable for grazing purposes.

The “sagebrush” is common, growing on good soil. The
“grease wood is rather common on alkali soils. Cactus abounds
on the dry slopes. Along the running streams are willows,
cottonwood and birch. Pines abound on the mountains and
also occur in the valleys of the hills.

The Medicine Bow Mountains are clothed with a dense
growth of pines, chiefly P. Contorla. In many places the
ground may be covered with a dense mass of fallen logs, often
apparently one-fourth as many as are standing. High up on the
mountains the pine gives place to the spruce, growing large and
very straight. In wet mountain valleys, the quaking aspen
abounds. Cedar is also common.

The Dakota sandstone, along the Front Range in Colorado
and New Mexico, forms the prominent “‘hog-back” ndge. On
Rock Creek it affords excellent beds for building purposes.
The other Cretaceous groups above are mostly shaly; the
Fox Hills everywhere is easily recognized.

The following named fossils were collected, all of them
mollusca: Helicoceras vespeieones, Ancylocevas uncum, A.
annulatum, A. Jenneyi, Scaphiits nodosus var. plenus, ‘Bacu-
lites ovatus, £8. compressus, Hammea minor, H. occiden-
talis, ‘Pseudobuccinum Debrascense, Fasciolaria cretacza,

— th

“i

Bones of Diplodocus as found in the quarry in Six Mile Gulch, two miles north of Wilcox, Wyo., on
Union Pacific Railroad

GEOLOGY OF THE LARAMIE PLAINS

F. buccinoides, F. Culbertsoni, Anisomya borealis, Limatia
occidentalis, _Chemnitzia centhiformis, Limopsis paraoul,
Axinea subimbricata, Cardium speciosum, “Pteria (oxytomia)
erecta, ‘P. perpleura, ‘P. linguiformus, PCactra_nitidula,
Nucula subplana, Pteria gastrodes, Yoldia scitula, Y.
evansi, Pteria fibrosa, Trigouarcar obliqua, Endocostea
typica, Inoceranus altus, I. Howelli, I. crispii, [tenuilineatus,
I. Balchii, I. tenuirostratus, 1. Vanuxemi, I. problematicus,
I. deformis, I. Sagensis, I. proxinus, I. Simpsoni, I. barabini.
The indurated Fox Hills strata are often entirely made up
of Inocerami, some very large.
The following is a section of strata seen in the Como anti-
clinal:
1. 45 feet of mostly brown sandstone forming the crest
of the hill—Dakota.
2. 55 feet of shales, may also be Dakota.
3. 2 feet gray sandstone.
4. 60 feet marine Jurassic. Soft gray and chiefly a sandy
clay.
5. 5 feet of red shales.
6. 10 feet of yellow sandstone.
7. 5 feet of red shales.
8. 10 feet of yellow sandy layers.
9. 44 feet of red banded beds.
Contains thin calcite plates.
10. 18 feet of blue laminated clay.
11. 5 feet, one bed of gray sandstone.
12. 18 feet of blue shales, with occasional solid layers.
Contains plates of calcite.
13. 6 feet of yellow sandstone.
14. 250 feet of dark, soft laminated shales.

— 90s

ajeym Aue uey} iadie] Sem 19WIWIMS SiY | *PeBOslIeY }108q4 UOjUL) yo you puno4
*BUIWOAAA 40 APISI@AIUP) ‘UINESNLU a4} U| Pe}UNOW ‘BuUO| joa} aul ‘sMinesneUl|ese|\| & $0 Seppe BY
a ————————______

GEOLOGY OF THE LARAMIE PLAINS

15. Gray sandstone.

16. 16 feet of shales.

17. 4 feet of gray shales.

18. 75 feet of red beds.

19. | foot of gray beds.

20. 11 feet of red beds.

21. 5 feet of gray npple-marked sandstone.
22. 12 feet of soft red shales.

23. 11 feet of gray sandstone.

24. 22 feet slope to railroad station.
In above sections | and 2, Dakota............. 100 feet
Nos. 3 to 17, inclusive, are Jurassic.............2,201 feet
PiccambOutony 4 are: Lriassies 260. a. onice es Uctakes, GAA feet

Although no fossils have been found as yet in the Triassic
of the West, yet its thickness, well developed, and its uniform red
beds cause it to be easily recognized. I have seen it on the
Colorado River in Texas, in New Mexico, and at the Garden
of the Gods in Colorado, where it forms such curious figures
and stands on edge, forming spires over 200 feet high. Here
it is largely pebbly. It is often beautifully rpple-marked and
often contains beds of gypsum. On the southern border of the
Laramie Plains, I observed 36 feet of white gypsum with about
1,000 feet of red beds above and yellow beds below. Near
the Grand Canon of the North Platte, there are undoubtedly
several hundred feet of Triassic, including the bright brick-red
strata, some of it beautifully ripple-marked. Att its base are shaly
beds with numerous chalcedonic concretions. Some of these, if
cut and polished, would form beautiful, agate-like ornaments.
Below this was observed about 40 feet of drab and buff lime-
stone, containing in the upper part numerous minute geodes.

—31—

ul Mou sauog

HIOA MAN ‘AlO}SI}{ [BANJEN FO UUNasN) UBOLoWY
“PBOIIEY OplBq UOIUP) UO “OAAA ‘XOD|IAA PIO FO YOU Saji OM} ‘YO/NH all iN X!S *AuUBND JO M21 A

GEOLOGY OF THE LARAMIE PLAINS

The Jurassic beds are well exposed in the Como anticlinal,
in the Freezeout Mountains, and the Freezeout Hills, and on
Little Medicine. In the upper portion chest layers are occa-
sionally present. [ower down are found mollusca of the fol-
lowing species, viz: | Camptonectes extenuatus, C. bellis-
triata, Ostrea strigilicula, Pecten Newberryi, ‘Belemnites
densus, Belemnites ACucronata, Trapezium subaequalis.

But it is the upper Jurassic that has made this formation
pre-eminently interesting, that has attracted people from every
direction to Wyoming, to dig out and view the wonderful fossil
treasures, the saurians small and large, and dinosaurs over 100
feet long. The world wonders at the discoveries. I only saw
portions of the skeletons, including a femur of a brontosaur, at
Laramie University, 69 inches long. I obtained the vertebral
joint of a dinosaur one foot in diameter. The leg bones of the
brontosaur would indicate a height of at least 15 feet.

Fifty species of saurians have been taken from these
beds. Some of the dinosaurs were reptile-footed, some were
bird-footed, some were beast-footed. Some were related to
the crocodile, others presented the characteristics of birds.
Some were carniverous, others herbiverous. Some were cov-
ered with bony plates, others had horns. The stegosaur had
a series of pointed plates rising as spines three feet high along
the dorsal ridge. ‘The atlantosaur of Marsh had a thigh-bone
over six feet long.

Twenty-five years ago Prof. O. C. Marsh of Yale Univer-
sity quarried from the beds at Como bones of larger animals
than had yet been found. They were chiefly saurians and
varied from the size of a small animal to that of the atlantosaur,
130 feet long. After that for ten years Professor Marsh worked
more or less at these beds.

arr

THE FOSSIL FIELDS OF WYOMING

The various Government surveys have at some period
within the last thirty-five years examined the geology in part
of the Laramie Plains and vicinity. In 1842, Captain (after-
ward General) John C. Fremont and party passed down the
North Platte Canon and barely came out with their lives, losing
nearly all their outfit.

Fremont in his report speaks of passing through North Park
and the Laramie Plains, and of the wonderful variety and beauty
of the flora.

In the following pages I quote from the reports of Clarence
King, Amold Hague, F. V. Hayden, J. J. Stevenson, Marvin
and Endlich.

Amold Hague, in “Geology of 40th Parallel,” speaking of
the Laramie Plains, says: ‘“They may be 80 by 30 miles and
are limited on the north by the hills at Como. On the south
they are shut in by the coming together of the Medicine Bow
and Laramie Ranges near the 41st parallel. The plains are
elevated from 6,800 to 7,300 feet above the sea and the surface
is so undulating that in the distance it seems to be apparently
level, with ridges 100 to 200 feet high.

“The Laramie Hills on the east are a continuation of the
Colorado Range and are scarcely |,500 feet above the plains.
The Medicine Bow on the west rises 3,000 to 4,000 feet
higher.”

Clarence King, in the “Geology of the 40th Parallel,” says:
“The Laramie Plain is essentially a broad, level upland of the
Colorado cretaceous.”

Hague further says: “The Laramie Hills lie chiefly
between 41° and 42° north latitude, extending to Laramie
River on the north and Cache la Poudre on the south, having

—34—

GEOLOGY OF THE LARAMIE PLAINS

a broad summit and an altitude of 7,800 to 8,300 feet above
the sea, with only one peak as high as 9,000 feet.

“The drainage from the Laramie Hills is all eastward and
no streams flow west,. with a few springs at the base of the hills
that afford a small supply of water.”

“There are but few trees on the summits, with some pines
in the valleys and on the slopes.

“The Laramie Hills form a single anticlinal range, its central
mass a heavy body of metamorphic granites of Archean age,
with Paleozoic rocks on the flanks resting at 4° to 10° against
the west side of the slopes.”

Hayden in his report, 1867-1869, says that the Laramie
Range forms one of the most complete and beautiful anticlinals
seen in the Rocky Mountains. It extends from a point near
the Sweetwater, southeastwardly, curving around until lost in
the main range near Long's Peak, but Hayden considers the
Laramie Plains to be not over 100 miles long. The nucleus
of the Laramie Hills is red syenite, flanked on each side by
Paleozoic and Mesozoic, with Tertiary in some places, inclin-
ing at different angles. A vast deposit of Cretaceous and Ter-
tiary was formed in this region with a small percentage of
calcareous material. “The Cretaceous amounted to 5,000 feet.

Clarence King in the ‘Geology of the 40th Parallel” con-
siders the Medicine Bow granite later than that of the Colorado
and Laramie. The extension of the Medicine Bow south of
Wyoming is overflowed by a rhyolite mass. Medicine Peak
consists chiefly of white quartzite nearly 2,000 feet thick, trending
north 20° to 25° east and dipping east, the quartz being
cut by a dioryte dyke. In the rocks of the Laramie and Medi-
cine Bow are found quartz, orthoclase, plagioclase, hornblende,
mica, chlorite and calcite. In other respects the ranges difler.

35—

Skulls of Titanotheriums in the museum, University of Wyoming, Laramie, Wyo.
Found forty miles north of Rawlins, Wyo., on Union Pacific Railroad

GEOLOGY OF THE LARAMIE PLAINS

Graphite occurs in the Laramie Hills. Among the western
foothills near Brush and Cottonwood creeks are quartz veins
which carry small quantities of gold, also magnetite and red
and brown garnets. At several points along the Laramie
Range the Upper Carboniferous is found resting directly on the
Archean. This has been mentioned also by Hague.

Amold Hague’s general section of the Jurassic and Cre-
taceous as published in ‘“‘Geology cf the 40th Parallel” is as
follows:

Section southern part of Laramie plains,

Jurassic —

1. Friable white sandstone
2. Reddish brown sandstone with thin layers of va-

|
|
riegated clays and marls ( 100 feet.
3. Cream-colored sandstone and marls J
4. Bluish gray cherty limestone + 25 feet.
5. Grayish white sandstone r 75 feet.
Triassic—
6. Yellowish red sandstone
7. Fine deep red sandstone \ 375 feet.
8. Argillaceous sand and shales with interstratified | ote
gypsum, one gypsum bed of 22 feet J ae
9. Red compact sandstone. t 250 feet.

10. Reddish gray sandstone.

11. Thin bed of gray cherty limestone.

12. Coarse friable ash colored sandstone with pebble |. 225 feet
of angular chert and Archean fragments J ner

The Como anticlinal consists of a steep mural face on the
north, sloping to the south, the main axis trending east and west.
Ridge bears north 609; east dip 20° to 25°. Hague section
shows:

Jurassic —

1. Compact yellowish brown sandstone, Dakota,
with some conglomerate layers.

Gray sandy marl.

Cream colored marls with thin sandy layers.

Bluish drab cherty limestone.

pL

THE FOSSIL FIELDS OF WYOMING

Jurassic (Continued) —

5. Fine ash-colored marls with thin beds of light
colored cherty limestone.

6. Gray and orange-colored marls with intercala-
tions of coarse sandy layers.

7. Reddish yellow sandstone.
Triassic —

8. Brick-red compact sandstone, Triassic.

Como Lake occupies an anticlinal valley.

In the marls both above and below the sandstone, a little
above the middle of the series, are Jurassic fossils, as Pentacrinus

astericus, Belemnites densus, Tancredia W arrenana, Trigonia
quadrangularis.

The Trias is included in the belt of conformable strata
wrapped around Elk Mountain, with Carboniferous beneath
and Jurassic above.

The west side of Rawlins quaquaversal uplift is marked by
concentric monoclinal ridges, the Trias showing above 700
feet thickness, with pink sandstone at base and deep red above.

Clarence King further says that nearly up to the 41st
parallel the red beds lie directly on the Archean from 300 to
800 feet thickness. They are also often seen resting conform-
ably on the Paleozoic.

“The Trias is essentially sandstone and includes both clays
and shales, and is of a prevailing brick red color. Next to
color the most noticeable feature is cross-bedding, which is
marked in the upper beds, but not seen near contact with the
Archean. Conglomerate zones appear in the lower part.
No organic remains have been found, but a few obscure pieces
of half-petrified and half-carbonized wood.

“On the east side of the valley of Laramie River, near the
Wyoming and Colorado line, are seen | ,200 feet of beds dipping
slightly north and west, and presenting a high, abrupt wall of

—38—

GEOLOGY OF THE LARAMIE PLAINS

nearly | 000 feet, with some gypsum outcrops in front. Gypsum
occurs in the Jurassic, but not so abundantly as in the Tnias,
and only in thin layers, the thickest being two feet.

“The Jura beds are more shaly, with some limestone layers,
while the Trias is essentially sandy.”

Hayden, in his report for 1870, speaks of a fine exhibition
of Mesozoic resting on the red syenite on Big Laramie River,
35 miles southwest of Fort Sanders, and for 20 to 30 miles
from its source the Laramie flows in a synclinal valley, the red
beds dipping on each side.

In Hayden’s report, 1873, A. R. Marvin, U. S. Geo-
logical Survey, speaks of the Trias as coarse grits and
moderately coarse sandstone with sometimes fine examples
of cross-bedding, and with conglomerates near the base.
A dark red color prevails. When uptilted and eroded they
form curious forms, as in the Garden of the Gods and Red
Buttes. The Jurassic forms a narrow zone in Colorado; north-
wardly it increases in width.

In the ‘Geology of the 40th Parallel,’ all the Cretaceous,
from the Dakota to the Fox Hills inclusive, are spoken as of
being well developed near the mountains, and are thus esti-
mated:

Laramie—1,500 feet.

Fox Hills—1,500 feet.

Colorado, including Fort Benton, Niobrara and Pierre—
1,000 feet.

Dakota—300 feet.

The base of the Dakota is fine grained, passing into a brown
sandstone.

In Hayden's report for 1874, he states that the Dakota
forms the ‘‘hog-back”’ of the front range and is from 200 to 400

-39 —

PBOINIEY f9BY4 UOIUP, UO *OAAA ‘MOG suld|pa|A| $o
Yyou sajius AjuaM} puNnoy “OAAA ‘altuBIe] ‘BUIWWOAAA 40 AjISi@AlUP) ‘WUNaSNW 2u} Ul SO1BD0UIYY 40 |[N4S

GEOLOGY OF THE LARAMIE PLAINS

feet thick. Along the margin of the mountains east of the
Wasatch it is generally present. Hayden says that it is doubtful
if any geologist would ever make three divisions of Nos. 2,
3 and 4 if he had first studied them in the mountains. Hence
the name ‘‘Colorado”’ used to include them seems appropriate.

After passing Cooper Station, five miles due east, black
clays of the Lower Cretaceous appear and six miles south-
east of Como on the railroad are excellent sandstone quarries,
and numerous vegetable impressions occur.

Clarence King, in his 40th Parallel Report, gives a gen-
eralized section of Cretaceous east of the Colorado range,
from the base up.

Number II. Fort Benton. |st—Dark plastic ferruginous and
argillaceous clays.

2d. Grayish blue clays, becoming dark calcareous near the
top, 200 to 500 feet.

No. III. Niobrara. 1Ist—Argillaceous limestone, some-
times merging into the dark Benton shales.

2d-—Light variegated marls; yellow color prevails.

3d—Yellow, white and cream colored marls with gypsum.

4th—Whitish gray marls.

5th—Yellow marls, with intercalated limestone.

6th—Bluish gray, soft, earthy beds, calcareous and argilla-
ceous of variable thickness, 100 to 200 feet.

No. IV. Fort Pierre. 1Ist—Black, carbonaceous, shales
and marls.

2d—Marly black arenaceous shales.

3d—Interstratified clay and sand, 250 to 300 feet.

Total, Colorado, 600 to 1,000 feet.

King, in 40th Parallel Survey, says that the Fort Benton
Cretaceous occurs as dark plastic clays and thin shales. The

THE FOSSIL FIELDS OF WYOMING

Niobrara is yellowish white chalky marls and impure limestone.
The Fort Pierre consists chiefly of clay beds. The Fox Hills
Cretaceous is a coarse argillaceous sandstone. Fish scales
occur in the Colorado clay beds.

»* In Hayden’s report, for 1874, he says that a few species
of plants probably began their existence in the Fox Hills and
continued on up into the Lignitic where they reached their
highest development. Remarkable concretionary masses often
characterize the upper Fox Hills beds, weathering so as to
leave caps at top. The Fox Hills is important in a biologic
view, for no animal and but few vegetables pass above. A
few plants began in the Fox Hills and continued up into the
Laramie.

King, in 40th Parallel Survey, says that the valleys of Big
Laramie, Little Laramie, Dutton and Rock Creeks are eroded
through Colorado shales and marls. North of the 41st
parallel, the Fort Pierre is the uppermost Cretaceous. South
of it, the Fox Hills sandstones form a broad belt extending
southwardly beyond the 40th parallel. On Laramie Plains, the
Fox Hills lie north and east of the Medicine Bow Range,
chiefly on Rock Creek and Mill Creek. South of Mill Creek,
the brownish gray sandstones carry carbonaceous shales with
seams of coal and impressions of deciduous leaves. On the
north side of Cooper Creek are thin seams of lignite. On
Cache la Poudre Creek, the Fox Hills attains a thickness of
1,200 to 1,500 feet, consisting of friable sandstone, rendered
impure by the presence of clay. From Medicine Bow to Car-
bon the Fox Hills forms the surface rock. Near Separation
Peak, the Fox Hills Cretaceous may be 3,500 feet thick to
4,000 feet south of Fort Steele. Four miles northeast the Fox

ais pe

GEOLOGY OF THE LARAMIE PLAINS

Hills is quite ferruginous and nearby the Platte River cuts
through nearly horizontal beds of Fox Hills.

The Fox Hills sandstones imperceptibly pass into the Lara-
mie above, which is largely of sandstone but contains more
clay and frequent carbonaceous shales.

East of the Rocky Mountains, the Fox Hills contains one
coal bed near its eastern limit. On Cooper and Rock Creek
are several coal seams. At Coalville, the workable coal is
Fox Hills. The upper limit of the Fox Hills is known by the
cessation of true Pelagic forms.

King says: “From the west, eastwardly, the Cretaceous
series rests with absolute conformity upon the Jura.”

At the Dutton coal bank the coal is overlaid by a very
friable, somewhat carbonaceous shale, full of dicotyledonous
leaves. This is again overlaid by a soft yellowish brown sand-
stone with fossil leaves in the lower beds. I did not have
an opportunity of examining the Laramie beds at any other

place.
Lesquereux divided the Laramie into three sub groups.

I st—Bitter Creek, or lower group, flora Eocene.

2d—Evanston, or second group, flora Miocene.

3d—Carbon, the third group, upper Middle Miocene.
Dinosaurs have been reported from the uppermost Laramie.

All the various geologists, who have spoken of the Laramie
group, assign its position at the top of the Cretaceous, with the
exception of Hayden and Lesquereux. They consider it to
be basal Tertiary, considered so by Lesquereux on account of
the fossil plants found therein.

In Wyoming and on the plains east of the Rocky Moun-
tains and south of the 41st parallel, the Laramie rests conform-
ably upon the Fox Hills Cretaceous.

—43

‘OAAA ‘Y891D 981] AUO7 Jo jsamM Sa||W Al} JUBLUdIBOSA

re

GEOLOGY OF THE LARAMIE PLAINS

Lesquereux, in Hayden’s Report for 1872, tells how
peat bogs are formed and discusses, in a full and interesting
manner, their formation, and also the Lignitic formations of
the Rocky Mountains. In this article he speaks of the coals of
New Mexico, Colorado and Wyoming. He says that the
Cretaceous, four miles west of Medicine Bow, passes under the
barren Lignitic sandstone. From this to Carbon the strata is
continuous in repeated undulations, forming basins, which
contain the Upper Lignitic, with remarkably thick beds of
combustible material. ‘The shaft at Carbon shows:

Ist—Clay shale and sandstone at top, 35 feet.

2d—Ferruginous shale with dicotyledonous leaves, 3 feet.

3d—Clay shale and sandstone, plants at top, 18 feet.
4th—Main coal, 9 feet.

5th—Fire clay, shale and dicotyledonous plants, 20 feet.

6th—Coal, 4 feet.

7th—Fire clay and shale, 8 feet.

8th—Coal, 4 feet.

In the above there are included 17 feet of coal in 101 feet of
depth. One mile west of Carbon, the upper coal is seen in a
cut under a thick layer of compact gritty sandstone with fossil
wood and streaks of coal near the base. Over the sandstones
are beds of fire-clay with silicified wood, and fossil dicotyledo-
nous leaves occur in the overlying shale.

At Point of Rocks the Lignitic series overlies Cretaceous No.
4, these constituting the axis of an anticlinal. Dipping west the
Upper Lignite strata is brought to the surface at Rock Springs.
At Point of Rocks, 80 feet of the Cretaceous below the Lignitic
is exposed and this is conformably overlaid by 185 feet of
Lignitic sandstone, bearing fucoidal remains. Twenty-five
feet above the base of this sandstone there is a bed of coal 8
feet thick.

—45—

THE FOSSIL FIELDS OF WYOMING

Half a mile east of Black Buttes we see at top:
Ist—Shaly sandstone, 10 feet.
2d—Argillaceous shales and clay, 7 feet.

3d—Coal streak, 3 inches.

4th—Argillaceous and sandy shale, yellowish, with many

dicotyledonous leaves, 10 feet 9 inches.

5th—Main coal, 8 feet.

6th—Chocolate colored fire clay, 5 feet.
7th—Black laminated shale, 10 feet.

8th—Coal, 4 feet.

9th—Shales and fire clay, 16 feet.

10th—White concretionary sandstone with many fucoids,

also is somewhat cavernous, 118 feet. [welve feet of coal is

here included.

The section at Rock ee shows:

Ist—-Main coal ....

4 ft.

At 117 feet dew afer, passing eherd Aire
shaly sandstone and clay.

2d —Coal worked two miles east .............

3d —at 149 feet, coal... A Cee, See OR Ot) eae

4th—at 268

5th—at 324 “

6th—at 353
Fih—ato7/
8th—at 420
Vih—at 447
10th —at 476
1 1th —at 485
1 2th—at 577
13th—at 606
14th—at 640
1 5th— at 668
16th—at 728

Total coal. “latin Pe | ) | | |

Emr N a ai ea
Nn
—_-
=)

PMN N=HWNNWAWS
aD iestamiew=aian =a pr semen
@o
5

— —
mee
lee ae il det
_
5

bo
>

456—

GEOLOGY OF THE LARAMIE PLAINS

Soapstone and sandstone between all the coals.

Below to 1,180 feet all sandstone. The record shows an
extraordinary development of coal strata, sixteen beds of
coal aggregating 48 feet. Some of this coal J saw last summer
in coal bins at Medicine Bow station and it certainly is a
beautiful and pure looking coal.

Lesquereux considers the Laramie of carbon to be Miocene
at Evanston; Upper Eocene at Raton, and Golden, Lower
Eocene. The vegetation he considers Oligocene; at Black Butte
and Rock Springs, Lower Eocene; at Point of Rocks, Rock
Creek and Evanston, Upper Eocene and Lower Miocene form
the flora.

These coals are often termed lignitic. Some even have
over |2 per cent of water in their composition, which would
show a relation to the English brown coals. The percentage of
ash is low, being from 2 to 6 per cent. Marvin, in Hayden’s
report for 1873, speaks of this, and also of their remarkable
purity. Iron pyrites occur in exceedingly small quantity. A
mineral resin is sometimes found. The following analyses are
from Hayden’s report, 1873:

pneu ateee i Vol os Fics Carba| (Ach . | 5 [coeality
(ea SCkr eee Af weal cd. SE ale Conner Wie:
133 | 6 toll 37 038) 490 51 | 68 |{ rep
1.31 | 46 50 3.22 | BI. Butte
1.34 8.5 130 to 50! 46 to 50 3to8 | Pt. of Rocks
1.29 7 36 fh. 5M (IGF ae Rock
1.23 6.25 39 th 2°52 SEG | Sa

Gre] BROADHEAD:
Columbia, Mo.

47 —

Bul WOK AA Ul ‘HBeAg B|WWBIB7 JO JOO} je YO|Ny 1Bvag dn Buiyoo7

TOPOGRAPHY OF CENTRAL
WYOMING

Few regions of the United States are so well fitted for topo-
graphical study as that of southern and central Wyoming,
through which the “Fossil Fields Expedition” passed. The
scenery is constructed on a generous scale; the immensity of
the high plains and the great size of the terraces are notable
features. ‘There is little vegetation to obscure the details of
the topography; the semi-arid climate tends at once to develop
and preserve these details, so that all of them stand out in clearest
definition.

Taking up the prominent types of topography in turn, we
may discuss each briefly:

MOUNTAINS: ‘These features are the most conspicuous in
the state, the frontal range of the Rocky Mountains and the
central portion of many other ranges are granitic; these are ordin-
arily characterized by their rounded summits, forming the well
known dome type of topography, so marked a trait of granitic
regions. ‘Their general appearance recalls the mountains of
Scotland or of Norway. Long slopes of waste cover the flanks
well up toward the top, and often only the summits are com-
posed of solid rock, and even here the process of weathering is
so rapid that they are destined soon to be wholly buried in
their own debris. The exfoliation of the granite is notice-
able in many cases and this accounts for the rounded summits
already mentioned. Because the mountains have become
thus weathered, they have lost many of the sharper features of
youth and have taken on the softer and block-like topography
of old age. This feature of the mountains dominates all of the
Wyoming scenery.

THE FOSSIL: FIELDS OF WYOMING

The flanks of the range are frequently bedded rocks; in
such cases their topography is much more rugged than that of
the central portion.

The variation so noticeable in the topography of the moun-
tains, as one range after another is visited, is due to differences
in the composition and the hardness of the rocks; differences
also in dip often make sharp contrasts in the topography of
closely associated areas.

Some of the ranges visited were well dissected anticlines
without a granitic core. The Freezeout Hills is a fine
example of this—it is well worthy of the visit of every geologist;
nothing in the country is more impressive than this magnificent
arch, opened up by subsequent erosion until the whole structure
is plainly seen on the lofty cliffs that wall in the subsequent
valley. Not only is the extent of the erosion shown but the
successive steps of its history are plainly indicated.

Toward the west the anticline that forms the Freezeouts
is barely notched—just a beginning has been made in the great
arch of red sandstone—but toward the east the anticline is more
and more deeply dissected as one approaches the older portions
of the streams that have accomplished the erosion. A pano-
rama of age-long activities lies before the observer as he looks
along the axis of this great anticline.

Passing away from the major folds which form the more
conspicuous elevations, one meets with numerous lesser folds,
which gradually die out as the distance from the mountains
increases. These minor folds are generally opened up by
erosion, so that the anticlines are well dissected. The hard
rocks have not been reduced to the general level of the country,
but stand up as rampart-like walls which sweep about as
they pass from anticline to syncline, in great curves, forming

TOPOGRAPHY OF CENTRAL WYOMING

the most conspicuous topography to be seen on the Piedmont
plains. No vegetation obscures them; there is nothing in this
country of magnificent distances to hide the sweep of these
natural ramparts as they wind back and forth across the country.
The softer rocks are quite fully removed as a rule, leaving the
depressions characteristically found where hard and soft rocks
alternate. The classic area of anticlines and synclines in
the Appalachian system of mountains is not only equaled but
excelled by those of Wyoming. There is a general tendency
in these smaller folds to be unsymmetrical; ordinarily the
steepest side is most completely removed, leaving the gentler
sloves standing as escarpments.

A fine example of this feature is seen at Aurora, where a
plunging anticline has had its steepest side removed, while
the less abrupt slope stands as an escarpment, several feet high,
in which lie the dinosaur beds made famous by the researches
of Marsh and others.

So well dissected is this particular anticline that a subse-
quent lake lies in its axis.

THE PLAINS: On passing away from the mountains
the folds gradually disappear, and the strata assume either a
horizontal position or they are inclined in some definite direction,
ordinarily away from the mountains. As a rule the strata are
monoclinal in this section of Wyoming, and as is usual in ~
such conditions the region is characterized by escarpments and
dip slopes. These features are especially prominent in the neigh-
borhood of streams, where subsequent erosion has had an
opportunity to work back along the strike of the rocks and
develop the escarpment feature. Away from the drainage
lines the plains are characterized by simplicity of topography,
though this depends largely on the nature of the underlying

51

BU|WOAAA Ul ‘BjOH Sa}eg ‘yoins vy

TOPOGRAPHY OF CENTRAL WYOMING

rocks. In some localities as on the rim of Bates Hole, complex
bad-land topography is found in the soft Tertiary rocks in
close association with the simple and smooth topography of
the harder Mesozoic rocks.

The present surface of the plains as a whole is discordant
with the underlying rock structure, that is the surface of the
plains does not agree with the dip of the rocks but rather bevels
off the dip. This feature indicates, beyond question, that the
region has been base-leveled.

Inasmuch as the Tertiaries are unconformable with the
Cretaceous rocks and are laid down upon these inclined Meso-
zoics in a horizontal position, it would appear that the base
leveling must have been post-Cretaceous.

The plains are covered by a thin, but effectual, layer of
gravel, which is largely siliceous in character, and largely local
in origin, as similar types are abundantly found in the still un-
weathered rocks.

This is especially well shown in the neighborhood of the
Fox Hills formation, where the great nodules, which character-
ize that formation, are found scattered about the surface of
the ground, left behind in the decay of the rocks. As the
mountains are approached, the character of the gravel changes,
there is a great accession of rocks which form the mass of the
mountains themselves; in such cases the gravel is of drift origin
in whole or in part.

TERRACES: The terraces are another of the important
topographic features of the region. The streams in most
instances are bordered by them, In many instances, as at
Cooper's Creek, there are three terraces lining the stream. They
are usually broad and reach heights of from fifty to one hundred
feet. The valleys in which these terraces are found are also

ye}p ‘AajjeA OYOS Ul PUNO} UO!ZBWIO} Y *saYyo} AA OUL

TOPOGRAPHY OF CENTRAL WYOMING

broad as a rule; even in the case of small streams they may be
several miles wide. In these broad valleys the streams are
almost lost and they meander back and forth in the most devious
way, indicating that the streams have well nigh reached local
base level. The broad undissected terraces contribute much
to form the block-like topography of the plains region. In
addition to the stream terraces, there is also a series of terraces
at the foot of the mountains. In most cases these are made up
ot confluent fans, which stretch along at the base of the moun-
tains for miles, parallel to their trend and only occasionally
sending out a tongue of gravel into the plain beyond. The
terraces of this sort are composed of coarse gravel where they
join the mountains, but this becomes finer as the plain is
approached.

The fronts of these terraces are often modified by stream
action. In such cases they possess steeper slopes than is other-
wise the case, for unless stream action has been present they pass
by gradual degrees into the plain. All of the terraces are modi-
fied more or less by subsequent drainage. “It is interesting to
note how many of these drainage lines have originated. In
most instances they have been located by the old-time buffalo
trails and by the more modern cattle trails. “These animals
passed from their grazing grounds on the higher lands down
to the streams by fixed trails which became deeper and deeper
with constant use. It was not long before a deep trail became
a passageway for water and soon grew into a regular water way,
which soon developed into a permanent stream, or at least
became a draw or gully. These draws can be seen in all
stages of development, from the slightly eroded cattle trail to
the well-developed ravine.

BASINS: Perhaps no feature attracts the attention of the
geologist to a greater degree than the basins which abound on

jo

YBIY 129} 000‘) [1BM |BOIWeA ‘SYOOI AiejUaUN|pas ay} Ul UOURD

TOPOGRAPHY OF CENTRAL WYOMING

every hand and are the most characteristic thing to be seen in
the region. They are usually oval in form; frequently they
have no outlet. They may or may not be occupied by water;
in the former case there is usually a wide belt of alkali surround-
ing the pond. These basins owe their origin to a number of
causes. Usually the basins occur in drainage channels and are
formed by the ponding of the streams by the debris carried in
by tributaries.

As is often the case, the tributaries work back along the
strike of the soft rocks and thus are enabled to carry down great
quantities of detritus, which the parent stream is unable to
handle. Under such circumstances a basin will result sooner
or later. In a few localities there was evidence of basins being
formed by tectonic agencies. The best example of this was
a basin in the neighborhood of Cooper's Creek, which had
been formed by the uplift of a small fold across the stream.

In the neighborhood of Harper, there were a few basins
that had been formed by wind action; indeed, the process of
construction could be seen going on in the strong wind which
swept the region a good share of the time. A characteristic
of such basins is that the coarse gravel is left behind, while the
fine debris, such as sand and fine pebbles, is swept away;
hence the bottoms of such basins are distinguished by the coarse
character of the gravel. In a few instances, solution basins
were observed; these were the round or oval-shaped basins
which occurred in limestone regions; they had no apparent
outlet. Such basins are not numerous, and they are not a
special feature of the region. No basins were observed that
could be attributed to glacial action; local glaciers have
doubtless occurred in the region, but they have left no well-
defined basins behind them as an evidence of their occupation.

OA AA ‘2/0 Sa}eg ‘UO!SOJ9 a\}seD

TOPOGRAPHY OF CENTRAL WYOMING

VALLEYS: None of the valleys calls for special attention
except that portion of the Platte Valley known as the Grand
Cain of the Platte.

Here, unknown to most, is one of the masterpieces of canon
topography in America. Not only is the scenery of the highest
order, but the structural features revealed are of extreme
interest. Here, in magnificent vertical section, the whole range
of rocks, from the Archean up, can be studied in almost unbroken
series. In the region of the cafion, the rocks dip quite uniformly
in a northerly direction. ‘The river crosses the strike as a whole,
though it meanders more or less as it passes through the cafion.
From a topographical point of view there are two especially
interesting points to be observed. First is the contrast of the
topography between the granite portion of the canon and the
sedimentary rock portion. In the former case the river is nar-
row and confined between vertical walls of granite a thousand
or more feet high. The canon resembles a vertical cleft in the
ground, recalling in some of its features the well-known Canon
Diabolo of Arizona. On the other hand, as the river enters
the region of bedded rocks, the cafion takes on an entirely
different aspect; the walls recede from the stream in relatively
gentle slopes; the river itself has worn a broader channel; the
topography of the walls in this portion is also much more varied
than in the granite portion, since the clastics vary greatly among
themselves in regard to composition and character of bedding,
as well as in hardness. Here are brought out in great variety and
detail that common feature in cafions, namely, the combination
of platform, cliff and talus slope. The topographic beauty of the
canon is greatly enhanced by the gorgeous colors of the rocks,
especially those of the Triassic, with their brilliant reds and
browns. The second noticeable feature is the meandering

59—

‘OAAA ‘@|OH Se}eg ‘uO!sole aida]

TOPOGRAPHY OF CENTRAL WYOMING

character of the stream, pointing to its superimposed origin.
The Tertiary rocks lie horizontally upon the inclined Paleo-
zoics and Mesozoics. ‘The topography of the country indicates
that the river has been superimposed upon the earlier rocks
through the overlying Tertiaries. “The unconformity indicates
this, the fact that the Tertiary rocks have been more extensively
eroded on one side than the other, and that, on the side in which
the monocline plunges toward the river, the erosive forces have
been much more active down the pitch of the plunging strata.

The two points mentioned above are, perhaps, most notice-
able, though there are many others of interest.

No attempt has been made in this bare outline of the topog-
raphy of southern Wyoming to give a scientific account of the
surface features of the region; its only object is to call attention
to some of its salient characteristics with the hope that it will
influence others to study in detail the features, which the mem-
bers of the Union Pacific expedition were enabled to study only
in the most hasty and imperfect way.

GEORGE [> COLLIE,

Referee in Topography, Logan Museum,
Beloit, Wis.

=H

“09 % ATIVNoW ‘ONY

WaISKS ‘qd ‘S-'d 'N

van
A \ SNOILOSNNOO
\ :

: SLI ONY

znyo

OOIXIWN

= 21419Vd
: \ \ SN NOINN

~ MEE Rs . ; >))))
FAM NOB,

at

S :
Sees
LyOdaAayHs~ y
: Loy XIN@DHd )
NOSINSd——~__

:
<a3 ;
| TENA

A»

10100

opv

)
eR wen .
| )
O1HO;YNVIONI sonia /
003701] (

of Zz
LIOULIO |
SQidV¥ ONVYS-

3 K
: ; ANN3ASHO
POOVOIHO / at

\ovusvugan |

Dr, Sipe ae

Yd TYNOTIVN |}
BNOLSMO1I3A |
ANOLSMONISA™ %

em IOS
| J s

o

ALiLNd,
Nosiuuvo

PNP OR MA TON

About the various points of interest on ‘‘The Overland
Route’ can be secured by addressing any of the follow-
ing agencies of Union Pacific Railroad Company:

ATLANTA, GA.—Candler Building., 121 Peachtree Street—

Ti, TRS WANIN) IRUDIN SS DIDIMDIRS SS Re oooh oo conus cdbogoe ee General Agent
BOSTON, MASS.—176 Washington Street—

WILLARD MASSEY. _New England Freight and Passenger Agent
CHEYENNE, WY0O.—Depot—.

IDs LR. MBA DIISICIAIEE. 2 ie ame ache eleaniecia id Ono mer erG Ticket and Freight Agent
CHICAGO, ILL.—120 Jackson Boulevard—

RUDI MIN NVI aby Reactor ecctcrs ees, rons aMistad nian s oyalslete see ss General Agent
CINCINNATI, OHIO—53 East Fourth Street—

Will. TERS EGU INN G ROSE Re aie einer are ear ara General Agent
COUNCIL BLUFFS, IOWA—s522 Broadway—

JJs (CW NENOIS OD) Bees canes er eeein DoS Orioles City Ticket Agent
COUNCIL BLUFFS, IOWA—Transfer Depot—

Tel Ao EN ANP ATSC O)S Oh qisieholetia 6 Uae ae cure cma renny peo cci Ticket Agent
DENVER, COLO.—o035-—41 Seventeenth Street—

eC. PE RGUSON Aa Oe AIS aah TREE LIRA RPC Oe CATT ES General Agent
DES MOINES, IOWA—=3r10 West Fifth Street—

Je ASIN ORY DOs a on a eeciel n cro ead 6 pele ptencan Traveling Passenger Agent
DETROIT, MICH.—11 Fort Street West—

[BEER CEN OUNCES rat x cy toys caste ets ake a ee ne et Sunae te fone Bes fend, she General Agent

HONG KONG, CHR es Building—
. Gen. Pass’r Agent, San Francisco Overland Route
HOUSTON, TEX, —

Seen ee ACNG) BRON iz, 5 fear c cea eres Gen. Pass’r Agent,G., H. & S. A. R’y
KANSAS CITY, MO.—oor Walnut Street—

1 RC Ce 52/20 11 ee ee i een Ass’t Gen. Fr’t and Pass’r Agent
LEAVENWORTH, KAN.—o and 11 Leavenworth Nat’! Bank Building—

TAR io 1s Wed 2A ON 0 Dea a ore Aao eaciciic oc eClcioi caeeoneiae Seen General Agent

LINCOLN, NEB.—1044 O Street—

Bye OOS SON erate, fetuses nararots ets eneiavecaieirars aire ss russel, 01 af General Agent
LOS ANGELES, CAL.—557 South Spring Street—

Eee ©) Se Vue SOU son tien oie evelal a cosh atesertut orale a oder ucts General Agent
MINNEAPOLIS, MINN.—a2r South Third Street—

FeTiste ee SC ARRAY Beer poy ay ox ct cay cee ottaye, ero oye ....District Passenger Agent
NEW ORLEANS, LA.—227 St. Charles Street—

rise PARSONS i oder dered ic Gen. Pass’r Agent, M., L. & T. R’y
NEW YORK CITY—287 Broadway—

Nines 2) BERGE Sie Nae apiece dhedey estoy ce ease General Eastern Agent

NORFOLK, NEB.—104 South Fourth Street—

Vet ies ACR Grit Rew Ris ice 2 ee ee ers ...Commercial Agent
OAKLAND, CAL.—1122 Broadway—

Heo Ve BLASDE lb ae i nis .........Agent Passenger Department
OGDEN, UTAH—Union Depot—

ASS DLO Lavi murs ok Traveling Pass’r Agent, O. S. L. R. R.

OLYMPIA, WASH.—

PiCRPERCIVIAW tes antes ceatiecchste a creche semi Agent O. R. & N. Co.
OMAHA, NEB.—1324 Farnam Street—

ILA IEVEUN DOU boa pabaodmoDlbec City Passenger and Ticket Agent
PHILADELPHIA, PA.—830 Chestnut Street—

SACs IMME B © UIRINI a easc crc siete eycte eee ee rsieieencie rei etiate General Agent
PITTSBURG, PA.—707-709 Park Building—

GAGS AIR RUIN Gee Sai acre hae ert Ae ore oe ..General Agent
PORTLAND, ORE.—Third and Washington Streets—

CRiWeSHEIIN Gis Rep eee oto eee City Ticket Agent, O. R. & N. Co.
PUEBLO, COLO.—312 North Main Street—

1 MEU © RS ree Vas esa an ene se, kag. Bier ree Commercial Agent
ST. JOSEPH, MO.—sos5 Francis Street—

CIS UIVIMIG: Rae eee .Ass’t Gen. Pass’r Agent, St. J.& G.I. R.R.
ST. LOUIS, MO.—o03 Olive Street, Century Building—

GPO Wikre So 18 sate Se Oe Ee eon eae ...General Agent
SACRAMENTO, CAL.—1007 Schon Sirect=

SAUDIS S WAV VEACRIREA C Kea es eee 3 .Freight and Passenger Agent
SALT LAKE CITY, UTAH—2or Main Shee

TD) SEER REA GY GR Ds cp. ec Teteg Acne RA i. | ee een General Agent, O. S. L. R. R.
SAN FRANCISCO, CAL.—42 Powell Street—

SEGES EBOOMIE, aioe peers c 5 soar ae Pea con ete kee eee General Agent
SAN JOSE, CAL.—1r1o North First Street—

IFS) Wize, SAGIN GTB RGe on Re Scr alas Pe egos rls Agent Passenger Department
SEATTLE, WASH.—608 First Avenue—

Ee a OEIC Ss erie ee ee en ees General Agent, O. R. & N. Co.
SPOKANE, WASH.—426 Riverside Avenue—

15 OOP LON ISOIN ISS eheain aHolnss os Wp mee City Ticket Agent, O. R. & N. Co.
SIDNEY, AUSTRALIA—

Vie SOP RO UM eres ees Toe eee Australian Passenger Agent
TACOMA, WASH.—Berlin Building—-

NACE Dee byl DH Open be Minten Sela a daaiome oops odes Agent O. R. & N. Co.
TORONTO, CAN.—Room 14 Janes Building—

jt O2'GOODSEE Leer a sos cee ae Traveling Passenger Agent

YOKOHAMA, JAPAN—,4 Water Street—
General Passenger Agent, San Francisco Overland Route

L. MOHLER, E. L. LOMAX,

Vice- President and General Manager. General Passenger Agent.
W. H. MURRAY, W. S. BASINGER,
Assistant General Passengér Agent. Assistant General Passenger Agent.

2-I-I9g10-10M, OMAHA, NEB.