Geological Survey Bulletin 707
Guidebook of the Western United States: Part E. The Denver & Rio Grande Western Route
MAIN LINE OF RAILROAD FROM GRAND JUNCTION TO SALT LAKE CITY.
SHEET No. 9|
(click on image for an enlargement in a new window)
Elevation 5,442 feet.
Denver 603 miles.
On the right may be seen the branch line of the
Denver & Rio Grande Western that leads to Sunnyside, one of the
largest coal mines in the district and the only one that produces a
merchantable quality of coke.68 Plate LXXXVI, B, shows the
coke ovens at Sunnyside. The two lines run nearly parallel for some
distance but finally unite at the station of Mounds.
(See sheet 9, p. 232.) To the casual traveler the
country over which he has been riding, as well as
that which he can see about Mounds, probably appears to be barren and
valueless, but should he pass this way in sheep-shearing time
and have a few hours to examine the shearing plant
which stands just north of the station, he might change his mind, for
this is the center of a large sheep industry. It is said that 100,000
sheep were sheared at this plant during the season of 1916 and that many
sheep were turned away.
68The following description of the
mines at Sunnyside is given by Frank
R. Clark, who has made a careful geologic survey of the region:
Coal has been mined at Sunnyside since about 1900. The town, mine
tipple, and coke ovens are in the mouth of Whitmore Canyon at the end of the
Sunnyside branch, about 18 miles east of Mounds. Two
beds of bituminous coking coal, separated by 5 to 25 feet of sandstone
and shale, are mined here. The lower and thicker coal bed ranges in
thickness from 5 to 14 feet and the upper bed from 3 to 6 feet.
Mine development has been rapid and continuous since
the beginning, and now the workings cover several square miles. An
electric plant furnishes power for hoists and hauling motors, and light
for town and mines. Power is also carried by a high-voltage line
eastward over the mountain into Range Creek, a distance of 5 miles,
where it drives pumps which deliver all the water used at Sunnyside for
domestic purposes and for steam boilers. The daily output of the mines
is about 2,500 tons of coal, most of which is converted into coke in
beehive ovens. The coke and coal are hauled by "locals" from the
mines to Helper, where through freight trains are made up. Most of the
coke from Sunnyside is shipped to the smelter at Anaconda, Mont.
The coal at Sunnyside and throughout the Book Cliffs
has been generally burned at the outcrop, producing a reddish color in
the associated rocks. The burning has advanced inward along the coal bed
at many points for more than 1,000 feet and beneath 1,000 feet of
overlying material. The mine workings at Sunnyside have in several
places surrounded the burned-out areas, thus showing the extent of the
burning. The fire has penetrated the coal farther on the points of
ridges between drainage channels than it did where the coal outcrop
crosses the stream courses.
PLATE LXXXVI. A (top). BAND OF SHEEP.
One of the important industries in this part of Utah is sheep raising.
The bands of sheep, each band under the guidance of a herder or two,
range from the low grounds of the desert in the winter and early spring
to the highest ridges and plateaus in midsummer. Photograph by Frank R.
B (middle). COKE OVENS AT SUNNYSIDE.
The Sunnyside mine of the Utah Fuel Co. is not on the main line of the
railroad. but it is served by a branch which connects at Mounds. The
coal mined at Sunnyside is the only coal in the State that will make
commercial coke. Photograph by Frank R. Clark.
C (bottom). CLIFFS ABOVE HELPER.
The cliffs of sandstone underlain by shale are striking features as the
traveler looks up at then from Helper, but when seen from the top they
are equally interesting, for one can follow, with the eye, the various
beds and note the form of sculpture of each particular layer. Photograph
by Frank R. Clarke.
It must be remembered, however, that the sheep
sheared here do not depend upon this immediate vicinity for their
pasture, for the sheep herder wanders with his flock during the summer
into the high country of the San Rafael Swell (see Pl. LXXXVI, A)
and in the winter seeks the protection of the lower valleys. The sheep
would soon starve on a small area, but there is much open rangethat
is, unfenced Government landin this country and by constant
migration the sheep do well.
From the vicinity of Mounds the traveler may see that
the Book Cliffs, which he has been following, continue northward only a
few miles beyond the mine at Sunnyside, which generally can be located
by its smoke, and there swing to the northwest to the head of Price
River, near Helper, and there again change their course to a direction
a little west of souththat is, they encircle the north end of the
San Rafael Swell. The name Book Cliffs, however, is applied only to the
part that lies east and north of the Denver & Rio Grande Western
Railroad; the part that lies south of the railroad is known as the edge
of the Wasatch Plateau. All these features can readily be seen from the
train in the vicinity of Mounds.
Just west of Mounds curious hard masses of rock
which on account of their nearly spherical shape are frequently
referred to as "cannon balls" may be seen in the shale that forms the
cut edge of one of the terraces. These round masses of rock are known to
geologists as concretions,69 and they were undoubtedly formed in the
shale after it was deposited as mud in the bottom of the ocean.
69The origin of concretions is not well understood,
but they are supposed to be due to the collecting together in the mud of
certain mineral particles, in much the same manner as the molecules of a
mineral unite to form a crystal. Concretions, however, are generally
rounded, or at least they are without sharp corners or straight sides,
though they may take on a variety of forms, some of which are very
complex and fantastic.
Elevation 5,313 feet.
Denver 609 miles.
Elevation 5,415 feet.
Denver 614 miles.
Elevation 5,546 feet.
Denver 619 miles.
From the uplands at Mounds the road descends westward
to Price River, which it reaches at milepost 607. Here the traveler is
once more gladdened by the sight of green trees and small irrigated
farms in the river bottom. The valley becomes rather narrow, and at Farnham
the bluffs of shale encroach closely upon the river bottom. The shale hills are
gray and barren, but they form a background that
serves to heighten the color of the fields and trees.
From Farnham the railroad follows Price River
practically to its head. Irrigation is generally practiced in the
valley, but the supply of water is not sufficient to serve all the land that is
otherwise favorably situated. Towns have sprung
up along the railroad and are achieving more or
less success. The next town to be passed is Wellington,
which appears to be a thriving village, whose
most prominent building is a modern schoolhouse.
Northwest of Wellington the valley is more open, and
well-irrigated farms are abundant. The country on both sides of the
river is served by canals that take their water from the river
several miles above Price. Price is the county seat
of Carbon County, which was so named because of
the great beds of coal that are
found in the Book Cliffs. It is a general supply point for the
ranches in Duchesne Valley, north of the Book Cliffs, and in
Castle Valley, south of them.
For a distance of 4 miles above Price the course of
the river is southeastward and its bottom lands are fairly wide. The
railroad is in this bottom and affords good views on both sides of the
best part of the irrigated district. From this open valley the traveler
may see. the shale terraces extending toward the river from both sides,
like long fingers, and at point milepost 623 they approach so closely
that the river flows in a veritable shale canyon, with steep walls on
either hand that rise to a height of nearly 100 feet.
Elevation 5,840 feet.
Denver 627 miles.
At this point the river also changes its course,
coming out of the Book Cliffs in a course nearly due south. The valley
continues narrow, with shale bluffs and a narrow strip of irrigated
bottom land. Just beyond milepost 625 a branch line on the east (right)
leads to Kenilworth, a mining town that produces a notable part of the
coal shipped from this region. About a mile farther north, in a
valley so narrow as scarcely to provide room for a single
street, is the railroad town of Helper, which was so
named because here are kept the light engines that
serve the regular trains as "helpers" up the heavy grade north of the
town. The town is at the mouth
of the canyon that Price River has cut in the plateau
of which the Book Cliffs are the front. These cliffs loom up 1,500 feet
above the station and seem to interpose a blank wall against the further
progress of the railroad, but like many other things in this world their
appearance is deceptive, for the railroad has succeeded in following
the stream through the narrow cleft. A view of the cliffs from above is
shown in Plate LXXXVI, C.
The canyon above Helper shows at close range the
character of the coal-bearing (Mesaverde) formation. The lower part of
the cliff overlooking Helper is composed mainly of shale (Mancos),
which originated in the sea and therefore contains no coal. The rocks
above this shale are mainly sandstones, but there are also many beds of
shale, and in places there are coal beds, which range in thickness from
a few inches to as much as 20 feet. An old prospect in one of the thick
beds is shown in Plate LXXX, B (p. 195). The coal beds, however
thick they may be, can not generally be seen from the car windows, for
they are the softest members of the formation and consequently weather
back faster than either the shale or the sandstone, so that their
outcrop becomes covered with soil and broken rock. Sandstone makes up
the greater part of the formation, and its general color is light gray
or nearly white. It has been described as red, but this is a mistake, as
the formation contains no red sandstone, though a ledge on weathering
becomes a rusty brown, or if point a coal bed below it has been burned
it may have become a bright red, but these are not the inherent colors
of the sandstone.70
70The following description of the coal
beds and the associated rocks in the vicinity of Castlegate is given by
Frank R. Clark:
FIGURE 57.Geologic section at Castlegate.
At the mouth of Price River canyon nearly vertical
cliffs of sandstone and shale rise 1,500 feet above the river bed. These
cliffs are capped by beds of sandstone that form the
lower part of the Mesaverde formation. The beds that
compose the cliffs were laid down in fresh water or on the land. They
rest upon soft dark shale (Mancos), which was laid down in a shallow
sea that covered most of the country. The line between these formations
is generally drawn at the base of the heavy ledge-making sandstone or at the top of the main mass of marine shale.
The upper part of the Mancos shale in Price River canyon contains
several prominent beds of sandstone (see fig. 57), which wedge out
toward the east. The lowest of these beds crosses Price River about 3
miles below (south of) Helper, and the upper one crosses the river about
midway between the town of Panther and the tipple of the Panther Coal
The Mesaverde contains several coal beds which differ
in thickness from place to place but where thickest are of great value.
Coal is mined on a large scale along Price River canyon and its
tributaries at Kenilworth, 2-1/2 miles east of Helper; Panther, half a
mile south of Castlegate; Castlegate; Cameron, 1-1/2 miles northwest of Castlegate;
Storrs, 3-1/2 miles northwest of Helper; Standardville, 4-1/2 miles
northwest of Helper; and Hiawatha, 13 miles southwest of Price. The
coal at Castlegate was formerly coked, but as the Sunnyside coal proved
to be better adapted to coking, the Castlegate coking plant was
abandoned. Three coal beds are mined at Kenilworth. The upper and lower
ones are 18 to 20 feet thick, and the middle one is 4 to 6 feet
The Castlegate group includes four coal beds, which
differ greatly in thickness from place to place but are locally
minable. At Cameron the coal does not come to the surface but is reached
by a slope. The two beds that are mined are probably part of the Castlegate group. On
the north side of the river, at Cameron, a massive sandstone crops out
in a vertical cliff about 450 feet high. This sandstone is locally
known as the Castlegate "reef" and crops out for many miles from east to
west. (See Pls. LXXXVII, C, and LXXXVIII.) The sandstone gradually
becomes thinner toward the east and at Sunnyside is only about 150 feet
PLATE LXXXVII. A (top, left). INCLINED NORMAL FAULT. Displacement,
8 or 10 feet. As the surface is not offset by the fault the movement
must have taken place long before the present valley was cut. Photograph
by D. E. Winchester.|
B (top, right). VERTICAL NORMAL FAULT. Displacement, 60 or 80
feet. Photograph by M. A. Pishel.
C (bottom). CASTLEGATE. SIDE VIEW.
The sandstone pillar on the east (right) aide of the canyon. From this
point of view it appears like a slender tower of the native rock almost
ready to fall from the vibration of the passing trains, but when looked
at from the north after having passed through the "gate" the picture is
different, as shown in Plate LXXXX III. Photograph by Shiplers, salt
The section shown in figure 57 includes the rocks
exposed from point the diversion dam on Price River 3 miles south of Helper to
the Castlegate "reef" sandstone at Cameron.
Half a mile above Helper a branch railroad turns back
to the left up Spring Canyon to coal mines at Storrs, Standardville, and
other towns where mines have recently been opened, and about 2 miles
above Helper the Utah Railway, a new line built to replace the one from
Price to Hiawatha, connects the mines at Hiawatha, Mohrland, and Wattis
with the Denver & Rio Grande Western.
The scenery in Spring Canyon, as in many others on
the road, is dominated by great sandstones. This dominance is shown
particularly by the narrowness of the canyon. Where the base of the
cliffs is composed of shale the canyon is wider, as can be seen in the
first 2 miles above Helper, but where the canyon walls are composed
largely of sandstone, as they are farther up, the canyon is narrow,
barely affording room for the automobile highway, the railroad, and the
river. The walls of the canyon also show the effect of the different
rocks; where they are mainly shale they have a
pronounced slope, but where they are
mainly sandstone they are precipitous and in places vertical. Each spur
that projects into the canyon is preserved by heavy sandstone, and
therefore the characteristic feature of the canyon is the many sandstone
points which stand up like walls or dikes.
As the coal beds occur well up in the Mesaverde
formation, they lie near the tops of the ridges at the mouth of the
canyon, and the coal mines here must lower the coal by long inclined
tramways to the tipple,71 which is at railroad level. This form of
handling the coal is well illustrated at the Panther mine, near milepost
629. Farther up the canyon the coal beds lie nearer the creek level,
and they finally pass below water level and are seen no more.
71The term "tipple" is applied in the soft-coal
regions of the United States to the platform or building to which the
coal is delivered from the mine. The tipple generally stands well above
the railroad so that when the coal is dumped from the mine cars it
descends by gravity through screens and is thus sorted into different
sizes or grades before it reaches the railroad car in which it is
shipped to market.
Elevation 6,120 feet.
Denver 650 miles.
The most prominent mine and mining town on the
main line is Castlegate, at the mouth of Willow
Creek, which enters the main stream
from the east (right). The mines are on both sides of the valley
a few rods above the mouth of Willow Creek, and the
coal taken from them comes to a common tipple, which spans the railroad
at this place.
The name "Castlegate" was taken from that of the
peculiar gate-like passage 2 miles above the town, the sides of which
seem to be walls or dikes of sandstone projecting from the sides of the
canyon. When viewed from a point directly opposite it the rock wall on
the right looks like a thin finger, as shown in Plate LXXXVII, C,
but when seen from a point farther up the canyon the walls on the two
sides seem to project so far into the canyon as almost to obstruct it
and to bar the railroad from further progress. This aspect of the
gateway is shown in Plate LXXXVIII. As a matter of fact the two walls
are not directly opposite, though this fact is not indicated in the
illustration, but are offset a considerable distance, so that the
opening is not so narrow as it appears. It is, however, a striking
feature of the canyon and well deserves the name "Castlegate." The spurs
that form the gate are not the only projecting ledges of sandstone, for
each point or spur, whether it is at railroad level or high on the
mountain side, is bounded by great cliffs of gray sandstone hundreds of
PLATE LXXXVIII. CASTLEGATE. Projecting points of gray sandstone close in
on the valley, leaving only a narrow passage resembling a gateway in the
walls of some old ruined castle. The grade for the west-bound trains is
heavy, and the canyon is generally filled with smoke. Photograph furnished
by the Denver & Rio Grande Western Railroad.
Throughout the main part of the canyon the railroad
climbs steadily in order to cross over the top of the Wasatch Plateau.
For about 10 miles out of Helper the grade is 127 feet to the mile, and
though such a grade is not excessive it necessitates the use of extra
engines on some of the heavy trains to get them to the summit.
Northward the canyon gradually grows less and less
rugged and the walls decrease in height until just above the first
tunnel, 1-1/4 miles above Nolan, the thick ledges of
sandstone give place to weaker beds of muddy sandstone, shale, and
fresh-water limestone. Although these point beds are in general gray,
they belong to a different geologic formation from that which carries
the coal beds at Castlegate. This formation, the Wasatch,72
which appears just above the first tunnel, is generally red, and in
many places it is very coarse, but here it is light in color and is
composed of fine material. Where the less resistant rocks form the
surface the slopes become smoother and less steep and the general aspect
of the canyon is much subdued. These gray beds continue to a point about
half a mile above the station of Kyune.
72Wasatch formation was one of the first to be laid
down in the Tertiary period. At the beginning of this period there was a
wide uplift of many mountain ranges, and as soon as these ranges
attained considerable height above sea level they were vigorously
attacked by streams, which rolled great boulders down the steep slopes
and deposited them at the foot. The finer material was carried away from
the mountains by the streams, as similar material is to-day carried far
away from the place where it originated, and was distributed over the
fairly even surface. As water tends to drop coarse material first, the
boulders, gravel, and sand were dropped near the mountains, but the clay
was carried farther off, and finally all the earthy material found a
resting place on the surface of the land or at the bottom of a lake. Such a lake probably
existed in the Castlegate region, and in it were deposited the
fresh-water limestones and shales which in this region constitute 700 or
800 feet of the lower part of the formation.
From the very manner of its origin and mode of
transportation the Wasatch formation varies greatly in its composition,
which depends upon the source of its material and the distance to which
it has been carried. Such differences will be seen by the traveler long
before he reaches the end of his journey. One feature of the Wasatch,
however, is remarkably constantits red or maroon color, which is
characteristic of the formation generally throughout the Rocky Mountain
region and is the most reliable means by which it can be
Elevation 7,013 feet.
Denver 639 miles.
Elevation 7,170 feet.
Denver 645 miles.
The upper part of the Wasatch is composed mostly of
red clay or shale and appears to contain only a few beds of
sandstone. Some of these beds have been quarried extensively above
Kyune, where this part of the formation first makes
its appearance. As the upper part of the Wasatch
formation in this locality is composed largely of
soft material, the slopes are gentle and the
immediate hills are low. Here and there a harder or a thicker bed
appears at the surface, and at these places the valley becomes more like
a canyon. The railroad follows the boundary between the gray
and the red parts of the Wasatch formations for some distance above
Kyune, cutting in places into the gray beds and in places into the red
ones. A short distance west of milepost 643 the railroad leaves the red
beds and for a mile it traverses the light-colored limestones and
shales. In these rocks the stream has cut a canyon, which bears off to
the southwest. On rounding the point of the spur that projects from the
north the traveler comes into an open valley that trends northward, and
on the farther (west) side of this valley lie the bright-red beds of the
upper part of the Wasatch formation. These beds are brought down into
view again by a northward-trending fault, which has cut the rocks for a
long distance on either side of the railroad and has dropped those on
the west side at least 200 feet. This fault, which passes a few hundred
feet east of the station at Colton, has caused
the formation of the north-south valley. From
Colton a branch railroad extends southward up
the valley of West Fork to the towns of Scofield, Winterquarters, and
Clear Creek, where coal of about the same quality as the Castlegate coal
is mined. The surface of the plateau, being composed of soft rocks, is
not rugged, and it does not seem to be very high, yet several points
near Colton stand nearly 10,000 feet above sea level. The plateau is a
fine summer range for stock and affords pasturage for thousands of
Elevation 7,440 feet.
Denver 652 miles.
From Colton the railroad runs up a broad but short
valley in the Wasatch formation to the crest of the plateau at Soldier
Summit, where the main line of the Denver & Rio Grande
Western Railroad reaches its highest point in the
State of Utah. The summit of this pass was so
named because some soldiers under Gen. Albert Sidney
Johnston, who were returning from the Salt Lake Valley at the end of the
"Mormon war," were buried here. A brief account of this "war," taken
almost wholly from Bancroft's "History of Utah," is given in the
footnote.73 Recently the railroad company has built an
extensive yard on the summit to facilitate the movement of freight.
73The so-called "Mormon war" was the result of
friction and misunderstanding between the Federal judges and other
officers of the Territory of Utah and the Mormon people. As the Mormons
had settled here before the region had passed into the hands of the
United States, and as they had increased greatly in numbers, they
thought they should be allowed to conduct their
affairs as they saw fit. Accordingly the legislature of the new
Territory proceeded to pass laws that were acceptable to the church but
that were apparently obnoxious to some of the Territorial officers. As
the Mormons regarded the Federal officials as
"carpet baggers" there was increasing ill feeling on both sides. On one occasion the
records of the United States district courts were taken from a judge's
office during his absence and a bonfire was made of his books and
papers. He of course supposed that the records were also consumed and so
made affidavit on his return to Washington. The records had, in fact,
been removed and were in safekeeping; but this escapade of the mob was
noised abroad with many exaggerations and excited much unfavorable
After several years of friction no Gentiles could be
induced to accept office in a land where, according to common belief,
they could perform their duties only at the peril of their lives.
Bancroft sums up the situation as follows:
"It was now established, as was supposed, on
sufficient evidence, that the Mormons refused obedience to Gentile law;
that Federal officials had been virtually driven from Utah, and that one
at least of the Federal judges had been threatened with violence while
his court was in session; and that the records of the court had been
destroyed or concealed. With the advice of his cabinet, therefore, and
yielding perhaps not unwillingly to the outcry of the Republican party,
President Buchanan determined that Brigham Young should be superseded as
governor, and that a force should be sent to the Territory, ostensibly
as a posse comitatus, to sustain the authority of his successor."
In July, 1857, Albert Cumming was appointed governor
and at about the same time a force of about 2,500 men was sent from Fort
Leavenworth to put down the rebellion in Utah. This army was harassed by
a band of Mormon forces, and when it reached Fort Bridger, Wyo.,
late in the autumn, found itself with supplies sufficient only to carry
it through the winter and without stock to transport its equipment
into Utah even if the way had been open. The commander, Brig. Gen. A. S.
Johnston, decided that nothing could be done until the next summer, so
he went into winter quarters near Fort Bridger.
During this unexpected delay President Buchanan was
persuaded by Col. Thomas L. Kane, of Philadelphia, a Mormon
sympathizer, to send him as a commissioner to Utah to investigate
matters and see if a peaceable settlement could not be effected. Kane
reached Salt Lake City in February, 1858, and arranged a general conference,
which showed that most of the charges were without foundation.
When matters reached this happy stage of adjustment the new governor.
was sworn in, the President's proclamation of amnesty was read throughout
the Territory, and it was agreed that the army should enter Salt
Lake Valley without molestation.
In accordance with this agreement, Gen. Johnston with
his command entered the valley by way of Emigration Canyon on June 26,
1858, and marched to Cedar Valley, 6 or 8 miles west of Utah Lake. Here
he established a camp, which he named Camp Floyd. Gen. Johnston left
Utah in March, 1860, and the next year was given a command in the
Confederate Army. The soldiers under his command were sent in parties to
other camps as the threatening cloud of rebellion grew blacker, and it
was some of these parties that followed the trail eastward over Soldier
Summit and gave it its name.
On approaching the summit the traveler may notice on the north side of
the valley, only a short distance from the track, a mine at which
considerable work has been done. This mine, as well as one north of
Colton and some others on the west side of Soldier Summit,
were opened on veins of ozokerite,74 but
the operators have had difficulty in competing with ozokerite shipped
into this country from Galicia, and the mines have never been fully
74Ozokerite, or mineral wax, is a mixture of various
hydrocarbons, generally supposed to belong to the paraffin series. It
varies in color from black or dark brown to light yellow, but some
specimens are greenish. It may be as soft as tallow or as hard as
gypsum. The lighter-colored varieties yield the largest amounts of
cerasin, which is the refined product. The melting point of ozokerite is
considerably above that of commercial paraffin. It occurs in fissures
in the rocks and is thought to have been deposited from petroleum that
formerly circulated through these fissures. The deposits are of
different thickness, ranging from mere films to masses nearly 3 feet thick.
Ozokerite is used extensively for insulating
electric conductors, for making candles, for adulterating beeswax, as a
foundation for either waxes and polishes, to protect metal surfaces, and
for making wax figures and wax dolls.
It is reported that the Utah field has produced
750,000 pounds since 1886, but this amount is insignificant when
compared with the annual imports, which from 1910 to 1920 have ranged
from 900,000 to more than 8,000,000 pounds.
As originally built the railroad on the west side of
the divide followed Soldier Creek from its head to Thistle, where the
creek joins Spanish Fork. This route made necessary the exceptionally
steep grade of 4 per cent, or 211 feet to the mile. The operation of the
road over this steep grade was very expensive, for three or four or even
five locomotives were required to get a heavy train from Thistle to the
summit. Recently the railroad company has abandoned this steep grade and
has constructed an entirely new line which begins at Soldier Summit and
extends westward for a distance of 15 miles. The new line has a grade of
2 per cent, or 106 feet to the mile, and one locomotive can haul as many
cars on it as three locomotives could haul on the old line. The new line
also gives the traveler a much better opportunity to see the surrounding
country than the old line, which ran in the bottom of the valley.
The rocks exposed in the numerous cuts on the new
line are generally red or at least are banded with red. These red rocks
are the continuation of those that were seen about Colton and are
undoubtedly the upper part of the Wasatch formation. The rocks dip to
the north (right) at about the same angle as the slope of the
mountain side, but the rocks across the ravine on the north
side of the old line of the railroad are very white and carry no trace
of red material. It is therefore fairly evident, as shown in figure 58,
that the rocks in the cuts along the new line belong to the uppermost
beds of the Wasatch, and that the white shale and sandstone across the
valley are in an overlying formation which geologists have named the
Green River formation, from its wide distribution in the Green River
Basin, Wyo. This formation is especially prominent at the town of
Greenriver, on the Union Pacific Railroad, and forms the
picturesque buttes back of the town.
FIGURE 58.Section at Gliluly, showing relation
of the northward-dipping red Wasatch to the white Green River
The formations in this vicinity are the same as those
that the traveler saw in Grand Valley, Colo., between Rifle and De
Bequevariegated Wasatch shale at the base and white shale of the
Green River formation above it. (See p. 148.)
Elevation 6,968 feet.
Denver 657 miles.
Elevation 6,529 feet.
Denver 661 miles.
At the siding of Scenic, 5 miles west of Soldier
Summit, the traveler may look down on the north (right) and see not
only the old line of the railroad 439 feet below him but also
the loop over which he will pass in a few minutes.
The difference between a 4 per cent and a 2 per
cent grade is here brought out clearly, even to
those who are not familiar with the engineering
problems of railroad construction. Two miles farther on the road makes
a broad loop to the right, still in the Wasatch formation,
and returns along the mountain side at a lower level. A reverse loop is
made under the old roadbed at the station of Gilluly, and from this
point down through the canyon the railroad follows the right wall,
but far above the level of the old line.
The rocks which form the mountain side above the
tracks and which have been deeply cut in order to provide a
roadbed are all in the Green River formation. They are naturally dark,
but on weathering they turn intensely white. Experiments have shown that
oil in commercial quantity may be distilled from many beds of this
shale, and it is possible that gasoline and other grades of oil, as well
as fertilizer, may some day be extensively manufactured here.75
75As stated on p. 149, the Green River
shale is continuous north of
the railroad from Rifle, Colo., to Soldier Summit, Utah. The beds from which
oil may be distilled are
not so thick in Utah as in Colorado, but recent work
done in this region
by D. E. Winchester has shown that a great quantity of
this shale is available in Utah and that
it may yet be a valuable source of
petroleum when the fields that are now
productive approach exhaustion. The white shale which occurs at Soldier
Summit will yield on distillation at
least 16.8 gallons of crude oil to the ton.
Where the Green River formation is first seen it dips
to the north (right) 25° or 30°, but beyond the curve to the right,
above the abandoned station of Tucker, on the old line, the beds are
somewhat disturbed, and between mileposts 663 and 664 they are thrown
into a well-marked synclinal fold, which may be seen on the right.
The siding of Detour marks the junction of the old
and new lines and also the termination of this narrow part of the
valley. Below Detour the valley is more open, at least as far as Narrows
siding, where it is again constricted by the appearance of harder
Immediately below Narrows siding the lowest beds of
the Green River formation rise downstream, and half a mile beyond
milepost 672 the red beds of the Wasatch make their appearance beneath
the gray beds of the Green River. The Wasatch is bright red, and the
change in color is very striking. This outcrop of the Wasatch is very
different in composition from that east of Soldier Summit. There it is
generally clay or soft shale; here it is largely a mass of conglomerate
composed of boulders of all sorts of rock that occur in the Wasatch
Mountains. The presence of such masses of conglomerate made up of
boulders of this size is a sure indication that the material was derived
from high mountains and that it was not carried far by the streams
before it was dropped to form great boulder beds that now are
consolidated into massive rock. It therefore seems certain that a high
range of mountains once existed in this region when the Wasatch
formation was deposited in the early stages of the Tertiary period. This
range must have been old as measured by the standard in this mountain
region, whereas the present Wasatch Range is supposed to be
comparatively young. These statements, however, are not so contradictory
as they appear, for most mountain ranges have a complex history,
involving many movements up and down, and the Wasatch may not be an
exception. It may have had its beginning as a mountain range in early
geologic time, but that old range may have been worn down to a rolling
plain and later it may have been uplifted into a range like the present
Wasatch. In fact, such changes may have occurred several times.
The conglomerate has been a formidable barrier in the
pathway of the stream, and it therefore forms a canyon which is scarcely
wider than the stream that occupies it and which has given rise to the
name "Narrows" for the siding at its upper end. The conglomerate is 700
or 800 feet thick and forms the sides of the valley for several miles.
The character of the rock, as well as its brilliant red color, gives to
the canyon an individuality that distinguishes it from all the other
canyons on the line.
Soldier Creek flows directly west, and the railroad
takes a course toward a high mountain peak, one of the southern points
of the Wasatch Range, which lies due west of Thistle. The
most southerly point of this range is Mount Nebo, a peak which lies so
far to the south (left) that it is obscured by the low hills in the
The appearance of the valley improves in its lower
course; more of the ground is irrigated, and there are indications that
the train is approaching a town or a railroad junction. Just before
reaching the station at Thistle there is a complete change from the soft
rocks of the Wasatch formation to the hard blue limestone and red and
gray sandstone of the Jurassic system, which form a decided
constriction in the width of the valley.
Elevation 5,033 feet.
Denver 681 miles.
The railroad turns abruptly north and is joined at
Thistle by a branch line which traverses the rich Sanpete Valley and
extends as far south as Marysvale. This valley was early
settled by Mormon families sent out from Salt
Lake City by Brigham Young for that purpose,
in order to protect these outlying
settlements as well as those in the Salt Lake Valley, and in 1849,
the State of Deseret76 was organized. The organizers passed through
much the same experience as those who attempted to organize the State of
Jefferson in what is now Colorado, but their motives were obviously
quite different. The State of Jefferson was organized to protect the
people and their property from the lawless hordes that would be
attracted to the country by the discoveries of gold, whereas the State
of Deseret was organized to protect and strengthen the Mormon Church by
having the machinery of government controlled by the dignitaries of the
76The word "Deseret" is taken from the Book of
Mormon and means honey bee. It is written in the Book of Ether of the
people who came over the great water from the old world to the new: "And
they did also carry with them 'deseret,' which, by interpretation, is a
honeybee." The honeybee, or rather the beehive, is one of the important
symbols of the Mormon Church, and the word "deseret" is used as the
name of the most influential church newspaper, the Deseret News.
77Bancroft, in his History of Utah (pp.
439-440), describes the situation as follows:
"Until the year 1849 the Mormons were entirely under
the control of their ecclesiastical leaders, regarding the presidency
not only as their spiritual head but as the source of law in temporal matters.
Disputes were settled by the bishops, or, as they were also termed,
magistrates of wards, appointed by the presidency. The brotherhood
discountenanced litigation, but the population did not entirely consist
of members of the church. There was already in their midst a small
percentage of Gentile citizens gathered from nearly all the civilized
nations of the earth. It was probable that, as the resources of the
territory were developed, this number would increase in greater ratio,
and it was not to be expected that they would always remain content
without some form of civil government. Not infrequently litigation arose
among the Gentiles, or between Mormon and Gentile; and though strict
justice may have been done by the bishops, it was difficult for the latter
to believe that such was the case. * * * The Saints regarded their
courts as divinely commissioned and inspired tribunals; but not so the
Gentiles, by whom reports were freely circulated of what they termed the
lawless oppression of the Mormons. Thus it became advisable to establish
for the benefit of all some judicial authority that could not be
questioned by any, whether members of the church or not, and this
authority must be one that, being recognized by the Government of the
United States, would have the support of its laws and the shield of its
protection. Further than this, if the Mormons neglected to establish
such government, the incoming Gentiles would do so ere long."
To accomplish this purpose a convention composed of
"the inhabitants of the part of upper California that lies east of the
Sierra Nevada Mountains" was called to meet in Salt Lake City on March
4, 1849. A constitution was drafted for the State of Deseret, which was
defined as extending from latitude 30° to the border of Oregon, and
from the Rocky Mountains to the Sierra Nevada, together with considerable
territory that is now within the Republic of Mexico. A general
election was held at Salt Lake City on the 12th of March, and Brigham Young
was chosen governor of the new State. On July 2 the general assembly
convened, and on the next day Willard Snow, being appointed speaker of the house of
representatives, administered the oath or affirmation to the executive
officers. Bancroft (History of Utah, p. 443) says:
"Thus did the brethren establish, in the valley of
the Great Salt Lake, the State of Deseret. It was certainly a novel and
somewhat bold experiment on the part of the Saints, mustering then
little more than one-sixth of the number required for the admission as a
State, thus to constitute themselves a sovereign and independent people,
with a vast extent of territory, and calmly await the action of Congress
in the matter."
On July 5 Almon W. Babbitt was elected delegate to
Congress, and on the next day a memorial to Congress was adopted, asking
for admission as a State. Babbitt proceeded to Washington, but Congress
refused to recognize him as a delegate from a State which had no legal
existence. The Territory of Utah was provided for by an act of Congress
September 9, 1850, and President Fillmore appointed Brigham Young its
Soldier Creek, which the railroad has been following
from Tucker, is here joined by Thistle Creek, and together the two
streams form the Spanish Fork. The canyon at Thistle is narrow, and its
walls are composed of bluish limestone on the east and banded red and
gray sandstone or quartzite78 on the west. The blue limestone
contains marine shells which show that its age is Jurassic. It normally
belongs beneath the Cretaceous rocks, which are so conspicuous along the
railroad from Green River nearly to Kyune. Near Thistle the rocks dip
steeply to the east, but toward the north the dip decreases until they
lie nearly flat. They also change in character, for they become much
softer downstream and are composed almost
entirely of soft red shale with some beds of
sandstone. Beyond milepost 681 this sandstone has been extensively
quarried for building stone in Salt Lake City, but the growing use of
cement has led to the abandonment of the quarries.
78Quartzite is a term applied to a sandstone that
has been changed into a hard, dense flinty rock by the deposition
around the sand grains of silica from percolating water carrying material
of that kind in solution. A quartzite is much harder than a
sandstone, is more resistant to the weather, and is generally nearly pure
Spanish Fork is here joined by Diamond Fork, a stream
coming from the northeast (right), which, though rather small, has been
utilized by the United States Reclamation Service to bring water from
Strawberry River, a tributary of Green River, through a dividing ridge,
to irrigate some barren land in Salt Lake Valley.79 The
water obtained by damming Strawberry River is carried
through the ridge by a long tunnel and discharged into one of the head
branches of Diamond Fork. From this point it flows by gravity into
Spanish Fork and is diverted lower down, where it is most needed. The
traveler may see the diversion canal near the lower end of the
79The Strawberry Valley diversion (see fig 59) is one of the large projects that the
United States Reclamation Service has carried to a successful
completion. By this project water that is not needed where it falls is
taken over into another drainage basin and given to the thirsty land.
As shown on the map (fig. 59) Strawberry River is one of the head
branches of Duchesne River (du-shayne'), a stream that enters Green
River from the west. Strawberry River heads in rather open
country near the Wasatch Range, which has an average elevation of
about 8,000 feet above sea level. At that altitude the cultivation
of any but the most hardy grains and vegetables is impossible, so
that the water is of little value where it falls, but over the
mountains on the west there is not sufficient water
to irrigate all the land that is well adapted to farming. The problem,
therefore, was to bring the water of Strawberry River across the divide
to the lands that needed it so greatly. To accomplish this feat a dam
72 feet high was built across Strawberry River at a place called the
"Narrows," a constricted point in the valley below a part that is open
and well adapted to form a reservoir. A tunnel was then driven from one
of the tributaries of Strawberry River through the divide for a distance
of 19,897 feet (nearly 4 miles), so as to allow the water of the
reservoir to flow through and discharge into the head of Diamond Creek,
a tributary of Spanish Fork. The water flows down Spanish Fork to the
west side of the Wasatch Mountains, where it is again diverted into a canal for utilization, first
for the development of electric power and later for irrigation. The
hydroelectric plant is 3-1/2 miles below the diversion dam in Spanish
Fork, and the power is generated by dropping the water to the level of
that stream, as shown in Plate LXXXIX, B. The water is then carried to the south end
of Utah Lake and distributed to the land at that place and also on the
east side. This land has been partly settled since 1847 but has not been
fully developed because of the shortage of water. The supply from
Strawberry Valley will be sufficient to irrigate about 54,000 acres of
this land, and thus a great addition to the productive power of the
State is made at the expense of a very slight loss to that part from
which the water is taken.
FIGURE 59.Map of Strawberry Valley reclamation project. The dash
line shows the boundary of the Green River drainage basin.
PLATE LXXXIX. A (top). BONNEVILLE SHORE LINE.
Lake Bonneville shore line as it is marked on the west face of the
Wasatch Mountains at the mouth of Hobble Canyon, back of Springville.
Above this line the rocks are bare, and there is no trace of wave
action; below it the slopes are covered with mud washed into the lake
when it stood at this height. Photograph by G. B. Richardson.|
B (bottom). HYDROELECTRIC PLANT OF THE STRAWBERRY VALLEY RECLAMATION PROJECT.
After the water of Strawberry valley is carried by a long tunnel through
the Wasatch Mountains into Spanish Fork it is diverted into a canal and
dropped several hundred feet to the plant shown in this view. The
electric power which it generates is sold to near-by towns, and the
water is then used for irrigating the land. Photograph by the U. S.
Elevation 4,912 feet.
Denver 685 miles.
The Triassic red beds extend nearly a mile west of
the mouth of Diamond Creek, to a place where they are probably
terminated by a fault which separates them from the Carboniferous and
older rocks that form the core of the Wasatch Range. The
rocks of the mountains are of Carboniferous age
but are so poorly exposed and so complicated in
structure that it is useless to attempt to describe
them. From some limestones of this formation comes the hot sulphur water
which has made Castilla (cas-tee'yah) Hot Springs a noted resort.
The Wasatch Mountains, although not equal in height
to the Rocky Mountains of Colorado or the Sierra Nevada of California,
are nevertheless one of the dominating ranges of the continent, and
their peaks range in elevation from 10,000 to more than 12,000 feet. The
impressiveness of the range is due more to its situation than to its
elevation, but both unite to make it a noteworthy group of mountains.
During the great ice age this range supported a number of glaciers (see
the map opposite p. 244), but the glaciers were neither so large nor so
numerous as those of the Rocky Mountains.
Since leaving Canon City the traveler has been either
in the Rocky Mountains or in what is generally known as the Plateau
country, so called because it is made up of a series of plateaus of
different elevations, but when he passes through this canyon and
emerges on the west front of the Wasatch Range he finds himself in a
country that is very different from any that he has yet seen on this
journey. This region is known as the Great Basin, a land of desert
basins and of barren mountain ranges, which in general trend north and
south. The precipitation here is slight, ranging in this latitude from 5
to 8 inches, and that which falls finds its way into some deep basin in
the interior like Great Salt Lake, where the water, when it evaporates,
leaves the mineral matter that is carried in solution to form beds of
salt or soda.
The walls of the canyon, although steep, are
generally smooth and are covered, except in the higher parts, by brush
and dwarf trees of many kinds. In summer they are clothed in a soft,
beautiful green, with here and there an evergreen tree to accentuate the
softness of the foliage of the other trees, but in September, after the
frost has touched the dwarf maples of the higher slopes, the coloring
is magnificent. Many of the slopes are a blaze of scarlet from top to
bottom, and others show scarlet interspersed with brown and green. The
clumps of aspen give the landscape a touch of gold, and the whole scene
presents an unexcelled splendor of autumn colors.
The canyon grows broader to the west, and the
railroad is built along its north wall. On the opposite side, near
milepost 687, is the headgate where the water of Spanish Fork, including
that from Strawberry River, is diverted into a large canal, which is
soon lost to view as it follows the south wall of the canyon to the
mouth and there turns to the left to the area where its waters are most
The outlet of the canyon is not like the outlets of
most of the canyons that the traveler has seen but seems to be dammed
or choked by a great mass of gravel. Where first seen, a little below
the intake of the canal, the gravel is at railroad level, and its top is
flat, as if it had been washed down the canyon and deposited as a delta
in standing water. An examination of the opposite slope shows a terrace
of similar material about 100 feet higher. This terrace also appears to
have had a similar history, except that as it is the older of the two
deposits most of its gravel was washed away when the second terrace was
formed, and so only fragments remain where they have been protected on
the side slopes. These terraces are of the greatest significance in the
interpretation of the late geologic history of this region; to the
geologist they have much the same value that the cliff dwellings or
tables of cuneiform writing have to the archeologist. They constitute
the record of one of the most remarkable geologic events in this
countrythe flooding of the basin of Great Salt Lake during the ice
age to a depth of more than a thousand feet. When these terraces in the
Spanish Fork canyon were formed the water of Lake Bonneville, as it has
been called to distinguish it from the present lake, entered the mouth
of the canyon at the level of the highest terrace, and if a traveler had
then attempted to make a westward journey here he would have been
confronted by an inland fresh-water sea that extended from the Wasatch Mountains to the west
line of the State.80 (See fig. 60.)
FIGURE 60Map of Lake Bonneville (the area
indicated by diagonal shading).
80The Bonneville shore lines and broad flats that
the traveler has already seen at the mouth of Spanish Fork canyon and
the others that he will see before he reaches Salt Lake City will
doubtless convince him that at some time long ago the drainage basin of
which the present Great Salt Lake occupies only the deeper part was
filled with water to the highest shore line, or about 1,000 feet. This
old and vanished lake has been named Lake Bonneville, in honor of Capt.
B. L. E. Bonneville, who in 1832 to 1836 explored
much of the region formerly occupied by its waters.
The late G. K. Gilbert, who was recognized as the
leading authority on the history of Lake Bonneville, said, in speaking
of the highest shore line (U. S. Geol. Survey Mon. 1, pp. 94-99,
"If the Bonneville shore line were
far less deeply engraved than it is it would still be conspicuous by reason of its position.
As it is, no geologic insight is necessary to discover it, for it is one
of the pronounced features of the country. It confronts all be holders
and insists on recognition. The tourist who visits Ogden and Salt Lake
City by rail sees it on the Wasatch [Mountains] and on the islands of
Great Salt Lake and makes note of it as he rides. The farmer who tills
the valley below is familiar with it and knows that it was made by
water; and even the cowboy, finding an easy trail along its terrace as
he 'rides the range,' relieves the monotony of existence by hazarding a
guess as to its origin."
Gilbert followed this shore line, studied it in
detail, and mapped it throughout most of its sinuous course. The map
copied from his report (see fig. 60) shows the greatest extent of Lake
Bonneville as compared with the present Great Salt Lake.
The history of Lake Bonneville goes back to a time
before man was known on the globe, or possibly about to the time of his
first appearance, but in any event the conditions that led to the
formation of that great body of water could not have been due to man's
activities and hence must have been the result of climatic change.
Gilbert (U. S. Geol. Survey Bull. 612, pp. 96-97, 1915) gives the
history of Lake Bonneville as follows:
"The latest of the periods into which geologists
divide past time witnessed a series of climatic changes which affected
the whole earth, and * * * the element which recorded its changes most
clearly was temperature. There were several epochs of cold, and they
were separated by epochs of warmth. During the cold epochs the high
parts of the Wasatch Range held a system of glaciers, and in one of them
several ice tongues protruded so far beyond the mouths of
the mountain canyons that they heaped their moraines
on the floor of Jordan Valley, only a few miles from the place where
Salt Lake City now stands. In that epoch of cold the rate of evaporation
was far slower than now, and evaporation was at so great a disadvantage
in its contest with precipitation that there was immense expansion of
the water surface. When the lake was largest it was comparable in area
and depth with Lake Michigan; It had eleven times its present extent.
In attaining this great expanse the water surface rose to a position
more than 1,000 feet above its present level.
"To this great body of water geologists apply a
distinctive nameLake Bonnevilleand they have given much
attention to its history, which is written in shore lines, deltas,
channels, deposits, and fossils. The shore lines [Pls. LXXXIX,
A, and XCVI, B] appeal most to the traveler and may be
seen from car windows at several points.
"As a matter of definition a shore is merely the
meeting place of land and sea, or of land and lake, but as a matter of
land form it is much more. At the shore the lashing of storm waves works
changes in the land, giving it new shapes. At some places the land is
carved away; at others it is made to encroach on the water.
Where it is eroded the limit of erosion is marked by a cliff, and below
the water is a shelf of gentle slope. Where additions are made they take
the form of beaches or bars, which rise little above the water level and
are composed of sand or gravel. At some places a bar spans a bay from
side to side; elsewhere it is incomplete, projecting from a headland as
"The waves of Lake Bonneville were as powerful as
those of Lake Michigan and fashioned the shore into an elaborate system
of cliffs, beaches, and spits, and when the waters finally fell to
the lower levels they left behind the shapes their waves
had made. The base of each surviving shore cliff is a horizontal line,
and so is the crest of each beach, bar, and spit, and these features in
combination trace the outline of the old lake as a level contour about
the sides of the basin and the faces of mountains that were once islands
in the lake.
"In rising and falling the waters lingered at many
levels, and so there are many ancient shore lines, but two of them are
more conspicuous than the rest and have been named. The highest of all
is the Bonneville shore line, and 375 feet lower lies the Provo shore
line. The Bonneville line represents a relatively short stand of
the water and is conspicuous chiefly because it marks the upper boundary
of wave action. All the slopes below it have been more or less modified
by the waves, but the slopes above it retain the shapes which had been
given them by other agencies. The Provo line represents a long stand of
the water and is conspicuous because it is strongly sculptured.
"In all the early history of the great lake its basin
was closed, like that of the modern lake. The water, surface rose and
fell in response to climatic changes like that of its modern remnant.
The last great rising was the highest and terminated the series of
oscillations by creating an outlet. The lowest point of the basin's rim
was at Red Rock Pass [130 miles by rail north of Salt Lake City], and
when the water rose above that level the stream which began to cross the
pass descended to Portneuf River, a tributary of Snake River, the chief
branch of the Columbia. Through the creation of this outlet the
Bonneville Basin, which had previously contained an independent
interior drainage system, became part of the drainage system of the
Pacific Ocean. * * *
"The formation at the summit [of Red Rock Pass]
consisted of soft earth, and as soon as overflow began a channel was
formed. The deepening of the channel increased the volume of the stream
by lowering the outlet of the lake; the greater stream was more
efficient in deepening the channel, and these two causes interacted
until the stream became a stupendous torrent. The volume of water
discharged before the flow became steady was enough to supply Niagara
River for 25 years, but the record of the torrent's violence leads to
the belief that it lasted for a much shorter period. * * *
"The draining of the lake down to the Provo level
reduced its area by one-third and correspondingly reduced the quantity
of water annually evaporated. Two-thirds of the inflowing water was
then disposed of by evaporation, and the remainder was discharged
through the outlet. Only a great change of climate could restore the
balance between inflow and evaporation, and the change was slow in
completion. At last, however, the pendulum of temperature swung far
enough on the side of warmth. The outlet channel ran dry, the lake basin
was again separated from the drainage system of the Pacific, and the
lake began to shrink. So long as there was outflow the water was fresh,
but when the outflow ceased there began that accumulation of salt which
has made the water of the present lake a concentrated brine.
"At times in the history of the lake, especially
while the Provo shore line was being formed, the tributary streams
brought down sand and gravel, which they dropped at their mouths,
building deltas. When the water fell these deposits remained as
fan-shaped benches having steep fronts. The streams that built them then
dug channels through them. * * *
"In quality of water and in temperature Lake
Bonneville was as well fitted for abundant and varied life as the Bear
Lake to-day, and though the only remains yet found in its sediments are
fresh-water shells, we need not doubt that its waters teemed with fish.
We may confidently picture its bordering marshes as fields of verdure and its
bolder shores as forest clad; and we may less confidently imagine
primitive man as a denizen of its shores and an eyewitness of the
spectacular deluge when its earthen barrier was burst."
Some of the most prominent of these old shore lines
have been named. The highest, the one Visible as a terrace about 100
feet above the track, is called the Bonneville shore line. The one at
railroad level, which has not been named, represents a later stage of
water, when the northern outlet had been cut down below its first
position but not so low as it became later. It probably records the
position of a harder bed of rock, which the outflowing waters encountered
when they had partly cut the barrier that held them in place, and this
hard bed held the stream so long that it permitted Spanish Fork to build
at this height a delta of considerable extent.
In its descent to the lower level of the valley
the railroad cuts deeper and deeper into the delta,
and finally, near milepost 689, it comes out on a still
lower plain, which represents a later and lower stand of the
waters. This plain is extensive, and from its
even surface the traveler may get his first general view of the Great Salt Lake basin.
Originally this plain was only a desert, but now it is
dotted with farms, each protected by a line of tall poplars that may be
seen far across the valley. Utah Lake, a body of fresh water 30 miles
long and 6 to 10 miles wide, lies in the middle of the basin,
and beyond it are the barren slopes of the Oquirrh
Mountains (o'queer). Most of these desert ranges are not very high, but
they are striking features, for they rise, island-like, out of a wide
expanse of desert.
Elevation 4,724 feet.
Denver 691 miles.
The plain upon which the railroad is built is another
of the numerous unnamed terraces that mark the shore line of Lake
Bonneville and represent pauses of longer or shorter duration in the
gradual lowering of the water in the basin. This is well
developed about the station of Mapleton. The view
from the railroad at this point is particularly fine
because it embraces what appears to be the bottom
of the valley, so wide is it and so completely cultivated.
On the right stands the great blank wall of
the mountains, across whose front the Bonneville shore line (see Pl.
LXXXIX, A) can be seen as a mere thread separating the slopes
abovecharacterized by gashes cut by streamsfrom those
below, in which all roughness and angularity have been concealed by the
material deposited in the ancient lake. Along the foot of the slope,
within the irrigated lands, stretches a belt of sloping plain on which
most of the homes of the region are built. Each house has its protecting
row of slender poplar trees, which give the scene an aspect so foreign
that one seeing it might almost imagine himself on the plains of
northern Italy looking at the slopes of the Alps, instead of in the Salt
Lake Valley looking at the slopes of the Wasatch Mountains.
The abrupt change from the steep slope of the
mountain front to the nearly flat surface of the desert plain, except
where deltas and bars were built in the waters of old Lake Bonneville,
is very striking and doubtless will attract the attention of many
travelers. The traveler sees no foothills, no indication of a mountain
front, until he reaches the foot of the slope. What does the abrupt
change from mountain to plain mean, and has it any connection with the
geologic history of the region? It assuredly has a meaning, and the
processes that produced these mountains have had a most striking effect
in determining not only the surface features of this region but its
climate and its arid conditions. Long ago, as man measures time, the
rocks composing the crust of the earth broke along a line that now
coincides with the west front of the Wasatch Range, and the
part on the east side of that break or fault was
forced up many thousand feet, or the part on the west was dropped an
equal distance, or both movements took place to a lesser degree. It
matters not which side moved, for in any event the part east of the
fault now forms mountains because it was uplifted relative to the other,
or the other is now a low basin because it was depressed relative to the
part on the east.81 Although the principal movement probably
took place long ago, slight movements have occurred so recently that
they have broken across alluvial cones formed by small streams flowing
out of the mountains.
81The entire Great Basin, which extends from the
Wasatch Range on the east to the Sierra Nevada on the west, is
characterized by faulted mountains like the Wasatch. Such mountains are
generally known as "block mountains," for the reason that the crust of
the earth has been broken into great blocks by the faults and later
these blocks have been tilted in different directions. In the central
part of the basin the faults and consequently the block mountains trend
north and south, as may be seen on any good map of the region. The beds
of rock of which such a mountain is composed may originally have had a
simple structure or they may have been folded and broken in a most
complex manner. But no matter how complex the folding the block has
acted as a unit and has been tilted in the same manner as the horizontal
In the tilting the edge of the great block that was
elevated produced a mountain and the edge that was depressed formed a
deep basin, which later was partly filled by sand and gravel washed in
from the surrounding slopes. In many places the loose rock filling has
a depth of more than a thousand feet. Such a basin is generally deepest
in the center, and the slight precipitation that falls on the
surrounding slopes finds its way to the lowest point, where it forms a
shallow lake, but the water is soon carried off by evaporation and
there remains in its place only a dry lake bed, known in the Southwest
by the Spanish name of "playa." The entire basin is also frequently
spoken of as a "bolson" (bowl-sown'), a Spanish name meaning purse,
which has been applied to the basin because it resembles in shape a
Great Salt Lake is said to lie in such a basin,
though it really lies in several basins, which are so shallow that the
water extends from one to the other. In time of drought it too would
disappear were it not for the large supply of water it receives from the
high ranges on the east.
Last Updated: 16-Feb-2007