Geological Survey Bulletin 707 Guidebook of the Western United States: Part E. The Denver & Rio Grande Western Route

A short distance west of the station at Grand Junction the traveler's view of the valley is fairly unobstructed, and he obtains an attractive setting for the picture of the town. The existence of this valley is due to geologic causes which can be easily understood by a traveler who desires to know something of the character of the rocks and of their attitude, or, as the geologist would say, the geologic structure. The lowest and therefore the oldest rocks lie in the great Uncompahgre Plateau or arch, which lies south of Grand Junction; the youngest rocks lie in the basin to the north and are generally known as the Green River formation. The dip of the rocks as they would appear in the sides of a great ditch, if one were cut from the top of the Uncompahgre Plateau to the middle of the Uinta Basin to the north, is shown in figures 37 (p. 148) and 48.

FIGURE 48.—Sketch section across the valley at Fruita, Colo.

The Mancos shale is much softer than the rocks either above it (to the north) or below it (to the south), and it therefore tends to weather away much faster and form a valley. As the formation dips only slightly toward the north, and as it has a thickness of about 3,000 feet, the valley which it occupies and which has been formed by its erosion is of considerable width. To the north the rocks above the Mancos shale cap the Book Cliffs, which were so named because the beds of rock when seen from a distance suggest the edge of a book lying on its side. To the south the underlying variegated sandstone of the Gunnison formation makes the slope that leads up to the great red cliffs on the Uncompahgre Plateau. The traveler may see these rocks, as already stated, soon after leaving the station at Grand Junction, and they are generally in sight on both sides of the road as far as Mack.

The peculiar shape and structure of the Book Cliffs (see Pl. LXVIII, p. 157) gives them a striking resemblance to architectural features. In their lower part they are composed of shale, which is capped by heavy beds of sandstone that lie almost flat. Nearly 1,000 feet of shale is exposed, and where it is not protected by blocks of sandstone that have fallen from the ledges above it has been cut by the rain into innumerable branching ravines separated by low ridges. Viewed from a distance when the sun is low enough to cast a shadow on one side of these dividing ridges the sculpture is marvelously accurate and sharply defined, resembling the venation of a leaf. The slope is steep, nearly 450, and the profile of the slope and the cliff above is well shown in Plate LXVIII (p. 157).

PLATE LXXVIII. A COLUMN OF SANDSTONE IN THE COLORADO NATIONAL MONUMENT. This national monument has been set aside because of the wealth of detail in the carving and the richness of the coloring of the erosion columns of deep-red sandstone which have become separated from the parent cliff by weathering. Photograph furnished by the Denver & Rio Grande Western Railroad.

The cliffs on the south are composed of great beds of red sandstone or white sandstone stained red by the overlying shale. At first sight these beds appear to lie so nearly flat that if they were extended they would reach entirely across the river valley and would lie far above the head of the traveler. When they are studied closely, however, they may be seen to bend down sharply as they approach the river, and in reality they pass under the stream instead of far above it. The bend in the rocks may be seen by looking back after the train has gone a mile or so beyond the station.

In this valley, as in most other irrigated parts of the West, the railroad does not traverse the area that is most highly cultivated, and the traveler may think that a large part of the valley below Grand Junction consists of land so highly impregnated with alkali as to be unfit for farming, but here and there he may catch a glimpse of the terrace or bench lands, which support the finest ranches in the valley. Along the railroad he may see some good ranches and orchards, and in striking contrast to them he may see in many places remnants of the original growth of sagebrush which covered the whole valley before it was irrigated and cultivated. This valley is the most arid part of Colorado, for, according to the records of the Weather Bureau, its annual rainfall is only 7.7 inches. The wizard that has transformed the scene here is water. This water may first fall in the form of snow on the high peaks of the Rocky Mountains, but early in June the warm rays of the sun reach the snowbanks and convert the snow into water, a part of which plunges roaring down the steep sides of the mountain to swell the torrents in the streams below, and another part finds lodgment in the crevices and open pores of the rocks and is kept stored there until the surface water has almost disappeared. Then the rocks gradually give up their stores, and this midsummer supply appears just when it is most urgently needed by the growing crops. But how can this water be gathered and spread out on the thirsty land; and if so spread out, will it be sufficient, or if sufficient in midsummer, will it be sufficient in September, when the driest part of the season is reached? In the semiarid regions of the West these questions are of the utmost importance, and several bureaus of the Government have been for years making exhaustive studies of all the streams to determine how much water they carry and in constructing engineering works by which the water in them may be distributed over the land. The work of measuring the quantity of water in the streams has been taken up by the United States Geological Survey, because water may truly be considered a mineral, and it is the duty of the Geological Survey to take account of all the mineral resources of the country. Most people of the West are familiar with this work, but those who come from the East are perhaps unaware that reports concerning the water supply of many regions or streams may be obtained free on application to the Director of the United States Geological Survey, Washington, D. C. The method by which the quantity of water flowing in a stream is determined is described below by Robert Follansbee.⁵⁶

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⁵⁶Without a thorough knowledge of the available water supply irrigation enterprises are not likely to be successful. The work of the United States Geological Survey in measuring the flow of the larger streams is especially needed to insure the prosperity of the West and has been developed to meet the need. It was begun in 1888, when a camp of instruction was established on the Rio Grande in charge of F. H. Newell, who later became the Director of the United States Reclamation Service. Here were developed the methods which laid the foundation for the present work of recording the flow of streams. From this small beginning the work was expanded until now there are in the United States more than 1,500 gaging stations at which the flow of streams is measured.

Records of stream flow are not only necessary in planning successful irrigation and water-power projects but are being used by the Reclamation Service in determining the inflow of the big reservoirs it is building, by the Weather Bureau in predicting flood flow in the lower Colorado River at Yuma, by the Forest Service in determining the available horsepower at undeveloped power sites in the national forests, and by irrigation and power companies at critical periods, especially during low water.

In determining the flow of a river the height of the water is first measured on a fixed scale called a gage. A local observer reads the gage height morning and evening and records the reading. If the record at the station is likely to be of great value, or if the station is in a remote place, it is desirable to use an automatic gage, which draws a curve on a chart showing continuously the height of the water, including every fluctuation. In May and June the warm days and cold nights cause alternate melting and freezing at the headwaters of streams that head in high mountains, so that they rise and fall regularly during a 24-hour day. The extreme daily variation may amount to 1 or 2 feet. On a gage that is placed near the head of the stream the highest stage will be reached during the day and the lowest during the night, but on one that is placed some distance downstream the highest stage may be reached during the night and the lowest during the day.

From the gage height and the contour or cross section of the stream bed at the gage, as determined by soundings made at several points in a line across the stream, the area of the cross section at the point of measurement is computed. The velocity of flow is measured with a current meter, and from the velocity and the area of cross section the quantity of water flowing past the gaging station can be determined. As the current strikes against the cups of the meter it causes them to revolve, and the revolutions in a given time are counted by means of an electrical make-and-break contact to determine the velocity of the current in feet per second.

In low water the meter is held on a rod and the engineer makes his measurements by wading. He first stretches a line across the stream to determine its width and then sounds every few feet across to determine its depth. Lastly he measures with the meter the velocity of the water at each point of sounding. Then, as he knows the width and depth of the stream, he can easily calculate the number of cubic feet of water passing this station each second (usually abbreviated to "second-feet") when the stream is at the stage at which the measurement is made.

Large rivers or even small streams at their flood stage can not be measured by wading, on account not only of the depth but of the swiftness of the stream, which may make it almost impossible to stand against the current, so that it may be necessary to work from a bridge or to span the stream with a cable from which the meter is suspended and held at the proper depth in the water by means of lead weights. To swing a meter weighted with 20 or 30 pounds of lead for several hours in measuring a swift river from a bridge is a form of exercise that is a sure cure for insomnia. If there is no bridge at the gaging station, the stream must be spanned with a cable, and the engineer must work from a car swung beneath it, as shown in figure 49. In this car he pulls himself along the cable to the points where measurements are to be made. A cable-car measurement is an even better cure for insomnia than a bridge measurement. In passing, it may be noted that if anything wrong happens to the current-meter equipment it always happens when the engineer is suspended in midstream while it is raining or while a wind is blowing what the loyal Westerner mildly terms "just a stiff breeze."

FIGURE 49.—Method of measuring the flow of a river at a cable station. The view shows the section of the river and the car, gage, and other apparatus.

Discharge measurements are made at different stages of the water. Perhaps half a dozen will cover the range between high and low water. These measurements, when plotted on cross-section paper, define a curve known as the "rating curve" for the station. From this curve the discharge for any stage of water can be estimated, and the engineer can calculate with sufficient accuracy for most purposes the daily flow from the gage readings furnished by the local observer.

If a river carried the same quantity of water each year it would be necessary only to maintain a gaging station at a particular place for a year, but as the flow varies widely from year to year it is necessary to maintain the stations for several years in order to determine the flow not only for an average year but for the wet and the dry years.

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As the traveler goes westward he sees that the Book Cliffs recede farther and farther from the river, and about 10 miles west of Grand Junction they begin to lose some of their picturesqueness on account of their distance from the observer. The red cliffs on the south become more prominent and are much more dissected into fantastic forms than they are south of Grand Junction. About 11 miles west of Grand Junction the pillars, towers, buttresses, columns, and domes become so striking that an area including them, opposite Fruita, has been set aside by the Federal Government as the Colorado National Monument. By this means they will be preserved and made accessible to the general public. One of these picturesque forms is shown in Plate LXXVIII. Fruita, as its name implies, is the center of an extensive fruit-raising district, but the best part of this district is on the terrace north of the town. Much of this land is devoted entirely to the raising of fruit; but, as shown in Plate LXXVII, A, other crops are raised between the trees while the orchard is maturing.

Just west of Fruita the railroad crosses Little Salt Wash and Salt Wash, two streams that head at the base of the Book Cliffs, about 20 miles to the north. The term "wash" is applied in the West to a stream or to the bed of a stream that is generally intermittent and that carries so much material that it clogs its own channel and is thus compelled to wander over a wide area. In some places where these streams are crossed by the railroad they have cut deep channels that have nearly vertical sides. Ordinarily very little water flows in these washes, but occasionally heavy rains or cloudbursts in the foothills send down a torrent that sweeps like a wall of water down the valley. The flood crumbles the banks of soft shale and clay, sweeps away bridges, uproots orchards and crops, and produces general devastation, although the rain that caused all this destruction may have been limited entirely to the foothill belt, none having fallen where the damage is done.

Near the village of Loma the river, which has been in sight in many places on the south (left) at the foot of the upturned red sandstone, turns to the left and enters a canyon in the Gunnison formation. The High Line canal of the Reclamation Service has been constructed farther west than Loma and provides for the irrigation of 35,000 acres by the gravity system and 10,000 acres by the pumping system. North of Loma several of the projecting points of the Book Cliffs are colored red and give to this part of the cliffs a different color tone from that which they have farther east. The red color is due to the burning of one or more coal beds and the consequent baking and reddening of the adjacent rocks. The Book Cliffs seem to have lost the abruptness that characterizes them near Palisade. They are broken into a number of terraces, which rise one above another until the height of the whole mass is about equal to that of the cliffs farther east.

Although the river has entered the canyon in the pink rocks on the south, the valley formed by the erosion of the shale and followed by the railroad continues in a northwesterly direction. Some of the land is irrigated, but most of it is in its original condition and the general aspect of the country is not particularly promising until the traveler reaches Mack, the terminus of the Uintah Railway, a narrow-gage line that leads from Mack northwestward over the Book Cliffs and down to Dragon and Watson, Utah. The region about Mack is barren and uninviting, but the grounds around the hotel built here by the Uintah Railway form an oasis in the desert. This quaint bungalow is embowered in trees, and on a hot day it makes an inviting resting place for those who have been exposed to the scorching sun or who are changing from one road to the other.

The Uintah Railway is used largely to transport gilsonite from the mines in the vicinity of Watson, Utah, to the main line of the Denver & Rio Grande Western Railroad, for shipment to market. The veins and mines are described below by D. E. Winchester.⁵⁸

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⁵⁸Gilsonite is a hard but brittle black hydrocarbon with a glassy luster, which occurs in great vertical veins at many places in northeastern Utah and is being mined extensively near Watson and Bonanza. The pure gilsonite is easily mined with a hand pick and is placed in large bags to be hoisted to the surface ready for shipment to market. The veins are rarely more than 10 feet in width, but they extend to unknown depths and in some places have been mined to a depth of 200 to 300 feet below the surface. The miners take special precautions to prevent fire, for the gilsonite dust is extremely explosive. No artificial lights are used in the mines, even at great depths.

The entire gilsonite output of Utah (about 20,000 tons annually) is hauled over the narrow-gage Uintah Railway to Mack, where it is reloaded to the larger cars of the Denver & Rio Grande Western Railroad.

Gilsonite is extensively used in the manufacture of paints, varnishes, roofing materials, and rubber substitutes.

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Although the shale which forms the valley that the traveler has been following from Grand Junction to this place, if he came over the main line, or from Montrose, if he came over the narrow-gage line, continues along the foot of the Book Cliffs to the region beyond Green River in Utah, the railroad does not follow it because near the State line it ceases to form a valley and the outcrop is rough and is broken by stream valleys that cross it. In order to avoid this rough country the railroad turns to the south (left) soon after leaving Mack and follows the river through Ruby Canyon for a distance of more than 18 miles. The gap in the ridge through which the railroad reaches the river can be seen on the left from the station.

Half a mile beyond Mack the railroad swings sharply to the south (left) and leaves the shale valley. It cuts through the sandstone rim that bounds the valley on the south nearly at right angles, disclosing the sandstones and variegated shale beds that underlie the dark shale (Mancos) of the main valley. The first sandstone to be seen is the Dakota, the lowermost formation of the Upper Cretaceous. Underlying the Dakota is the McElmo formation, equivalent to the upper part of the Gunnison formation, which has already been seen at a number of places. The McElmo formation has everywhere about the same character and when once recognized is easily identified wherever it is seen. It includes an upper member 150 feet thick—the one that is first seen after leaving Mack—composed of variegated shale and sandstone, which on account of its relative softness weathers back into gentle slopes. The underlying member is about 60 feet thick and consists mainly of sandstone, which is more resistant to weathering than either the overlying or the underlying shale and therefore stands out and makes terraces or benches on the hillsides. The sandstone is in turn underlain by a gray clay or shale, which has a thickness of about 100 feet. These rocks form the canyon walls for a distance of about 2 miles, but they are so soft that in no place are the walls very steep. Owing to the red and green tints, the color effect is rather pleasing, but it soon becomes monotonous, and some other color or larger masses of color would make a welcome change.

The structure or attitude of the beds in this part of the canyon is simple. The rocks rise abruptly at an angle of 30° from the shale valley on the north, but they soon flatten and for some distance lie flat or dip slightly toward the southwest. The railroad follows the valley of Salt Creek, but the bends of the creek are so short that they do not everywhere accommodate the railroad, and about a mile from Mack it cuts through one of the small bends by a short tunnel in the sandstone member of the McElmo.

About a quarter of a mile beyond milepost 472 the railroad reaches the river, and from this point to Westwater it follows the right bank. The canyon, because of its red color, is generally called Ruby Canyon, but the most strongly marked red rocks do not appear until the traveler is about half a mile below the siding named Ruby. Here the massive sandstone that underlies the McElmo comes up suddenly in a great fold,⁵⁹ which may be seen on the opposite side of the river. (See fig. 50.) The uppermost bed in this fold is not red but nearly white, although generally it is stained pink from the overlying McElmo shale. The white sandstone (La Plata) has a thickness of nearly 100 feet, but below it is a bed of somewhat softer sandstone, which is deep red. The fold is very short but steep, the beds having a dip of about 45°. The angle of dip decreases, however, and in a very short distance the beds lie practically flat.

FIGURE 50.—Short fold in massive sandstone (on the left of the westbound train) opposite Ruby siding, below Mack.

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⁵⁹The rock folds in the plateau district of Colorado and Utah are different from those which the traveler has seen in the Rocky Mountain region. Generally anticlines are great upward bulges in the rocks, in which the beds are nearly equally curved in all parts, as shown in A, figure 51. In the plateau region the general effect of an anticline may be the same, but the location and form of the fold may be very different, as shown in B. The beds are very strongly folded on the flanks of the anticline, but the area affected by the fold is very narrow. The traveler may see many such folds as that shown in B before he reaches Salt Lake City.

FIGURE 51.—Different types of anticlines.

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The sandstone which rises above water level just below Ruby siding is massive—that is, it is almost without bedding planes or lines of separation—and consequently it makes a canyon which has smooth, nearly vertical walls (Pl. LXXIX). The color, except in the uppermost layer, about 100 feet thick, is decidedly red, so that in general the canyon walls are a bright red, and the name Ruby is quite appropriate. A close look at the sandstone will show that it is not evenly banded like many of the sandstones in the region to the east, but that the marks along the edges of the beds—which indicate the form of the layers in which the sand was laid down—dip at all angles, or rather are generally curved, showing that the sand was carried into the place where it was deposited by strong currents of air or water, which cut away much of the sand that had been formerly laid down and in its place deposited layer after layer in a curved position. This process is termed cross-bedding, and an extreme example of it is shown in Plate LXXVI, C (p. 179). These beds were all laid down on the land, or at least no marine fossils have been found in them.

PLATE LXXIX. RUBY CANYON. This canyon takes its name from the deep-red color of the rocks. Its walls are generally smooth, and in many places they are vertical from top to bottom. The massive cliffs curve gracefully in conformity with the great sweeps of the river around the projecting spurs, first on one side and then on the other side of the canyon. Photograph furnished by the Denver & Rio Grande Western Railroad.

The graceful swing of the river from bend to bend and the corresponding curves in the smooth massive walls of the canyon are well shown in Plate LXXIX.

The rocks rise gently downstream, and near milepost 477 the canyon walls have a height of about 300 feet. Just a little below this point dark granite⁶⁰ appears in the bed of the river, and therefore 300 feet is about the full thickness of the sedimentary beds in this canyon. The granite is exposed on the crest of a small anticline or uplift, and in a few hundred yards it disappears. The upper surface of the granite is smooth and doubtless once formed the land surface upon which the sand was laid down.⁶¹

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⁶⁰The crystalline rock that constitutes the foundation upon which western Colorado and eastern Utah have been built presents different phases from place to place; in one place it may be a true granite, in another a gneiss, and in another a schist. As these phases grade into one another the exact character of the rock in all places can not easily be specified, and so it is here called granite because this term is in general sufficiently exact, and an attempt to differentiate the various kinds of crystalline rocks might be complicated.

⁶¹In the canyon of Colorado River just above Glenwood Springs the same granite or gneiss is exposed, and the stream has cut its channel in this rock to a depth of 1,000 feet. The quartzites, limestone (Ouray), and variegated Carboniferous rocks above the limestone, extending from the canyon just mentioned almost as far as Wolcott, are not found in Ruby Canyon. As many of these formations are of marine origin it seems probable that they were originally deposited over all this region but that later the sea bottom was uplifted so as to form land and then the streams and the weather slowly cut the rocks away until in places the formations mentioned were removed before the red sands were laid down, although in other places only a part of them were removed. Hence at different localities different formations rest on the granite.

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Although the river has been the principal agent in carving Ruby Canyon it has not done all the work, for the moisture in the atmosphere and the sand blown by the winds are very active in wearing away the rocks. The results of the work of both of these agents may be seen at many places. The moisture in the atmosphere dissolves the cementing material that binds the grains of sand together, and the wind mechanically removes the loosened grains. These agencies acting together eat out cavities in the canyon wall, most of them small, though here and there one is excavated into an immense alcove having an arched roof. Wind-driven sand cuts the hard rock like a sand blast, and as the texture of the rocks differs from point to point the cutting has produced grotesque, fantastic forms. At some places the sand blast has cut the finest fretwork; at others it has simply rounded off projecting points of rock so that they stand out as great domes or circular minarets. Many such features cap the solid canyon wall, but they are so far above the track that the traveler can see them only as he looks ahead at some projecting spur or back at the disappearing view. At one place a group of columns on a salient point on the canyon wall resembles a procession of Egyptian figures, as shown in the ornamentation of their temples, and consequently these are known as "The Egyptian Priests."

Beyond the place where the granite appears in the river bed the rocks dip gently downstream as far as milepost 479, where they are again elevated in a fold similar to that which has exposed the red sandstone just below Ruby. This fold is not so apparent from the train as that just mentioned, but by looking ahead from a point near milepost 479 the traveler may see it in the canyon wall on the right, and he may note traces on the projecting point on the opposite side. This fold raises the sandstone so high that the granite again appears in the river bed, rising at least 20 feet above ordinary water level and being visible from the train for about a mile. The river has had much greater difficulty in cutting the granite than in cutting the sandstone; the sandstone has been entirely removed, but the granite forms a very effectual barrier in which the stream has been able to cut only narrow channels, through which the water boils and tumbles, so that the rock is scoured and polished by the sand that the water carries over it. Pebbles accumulate in hollows of the rock and soon grind out deep holes where they are given a rotary motion by the current. Such holes, which are known as "potholes," are abundant in the granite in this canyon.

In places the massive sandstone overhangs the railroad, as shown in Plate LXXX, A, and the beetling cliffs afford ideal sites for the mud dwellings of swallows, which circle about such places in countless numbers. In other places the rocks assume fantastic forms, especially on projecting points between the sharp bends of the stream or between tributary canyons, as if mighty buttresses were necessary to support the vertical walls, but a general and solid massiveness and the nearly vertical character of the walls make a stronger impression upon the mind of the traveler than any other feature.

PLATE LXXX. A (left). OVERHANGING WALLS OF RUBY CANYON. The massive red sandstone makes very imposing walls in Ruby Canyon. In places it nearly overhangs the track. Photograph by Marius R. Campbell. B (center). THICK COAL BED. Old prospect entry on 15 foot coal bed near Helper. These thick beds of good coal will doubtless be greatly developed. Photograph by Frank R. Clark. C (right). COLORADO-UTAH STATE LINE. The boundary line between Colorado and Utah is well marked in Ruby Canyon. Photograph by Marius R. Campbell.

The granite disappears beneath the river bed near milepost 481, and the rocks below that point dip gently southwestward and the height of the walls gradually diminishes to the place where the canyon is crossed by the boundary line between Colorado and Utah. The boundary is marked by a monument at the left of the track and by a line painted on the cliff at the right, with "Colorado" on the east of it and "Utah" on the west. (See Pl. LXXX, C.) The canyon walls here are only about 200 feet high, and they decrease in height and impressiveness until the red sandstone passes below the level of the track near the point where the railroad crosses Bitter Creek, close to milepost 488.

Below Bitter Creek the walls of the canyon are made up of the softer beds of the McElmo formation, and they recede from the river, leaving a broad valley which at one time was selected as the site of a town that was to be named Westwater, but unfortunately for the founder his dreams were not realized, and the town to-day consists only of section houses, a water tank, and one or two farms. At this point the Denver & Rio Grande Western leaves Colorado River, which the traveler will see no more on this journey. By looking to the left (downstream), however, he will see that the rocks rise again and that the canyon assumes large proportions. Indeed, its vertical walls seem to be even more pronounced than those that mark its course above Westwater.

About a mile from Westwater the railroad crosses Cottonwood Creek, which heads in the foothills of the Book Cliffs. The road extends up one of the branches of this creek to the divide between it and some other small streams on the west. In climbing, however, the traveler sees the same rocks at the level of the track, for the rocks rise toward the west in a great fold that brings up the red sandstone again below Westwater. So, when the traveler reaches the siding of Cottonwood, which is at the summit, the beds which he sees are of the same age as those which he saw at the crossing of Cottonwood Creek, 4 miles to the east.

After journeying through the canyon for about 20 miles the traveler will probably be glad to leave it and to gain the upland, where he may see something more than rugged rock walls and muddy river. If the vegetation on the upland is not parched and dried by the summer's heat, the sego lily, Utah's floral emblem (Pl. LXXXI), may be seen here and there lifting its delicate head, though it stands so close to the ground that it is difficult to identify from the moving train. The wide expanse of upland also enables one to see the larger features of the surrounding landscape. One of the first objects to catch the eye on the left is a distant group of mountain peaks—the La Sal Mountains—whose highest point reaches an altitude of about 13,000 feet. One unaccustomed to judging distances in the clear air of an arid country can not say whether these mountains when first seen are 10 or 50 miles away, but careful measurement has shown that the nearest peak is about 30 miles distant. This mountain group was formed by the uplifting of the rocks in a great domelike mass, and if the light is just right the traveler may see the great cliff-like wall of red sandstone, with which he is now becoming familiar, on the east side of the mountains, where it has been uptilted by the movement. This group of mountains will be in sight for some time, and a little farther west it can be seen to better advantage.

PLATE LXXXI. STATE FLOWER OF UTAH. This delicate flower is commonly known as the Sego lily, but by botanists it is called Calochortus nuttallii. It grows in abundance on the higher lands of the State and is one of the most beautiful of the wild flowers. Photograph by Shiplers, Salt Lake City.

The railroad winds about in the low hills of the McElmo formation, which in places are somewhat picturesque on account of the great variety of their colors, but in general the outlook is not particularly pleasing. The scene, however, may be of great interest to one not familiar with it, for it gives him a good idea of the utter barrenness of a region where the rainfall is as scanty as it is in Grand County, Utah. In places the rocks are very dark, and the traveler may think that they have been baked to this dark color by volcanic fires and that many of the rock fragments are pieces of lava. The geologist, however, knows that the rocks of this region are not volcanic. In fact, all the rocks composing the McElmo and Gunnison formations were laid down as sediments in lakes or ponds or in the beds of streams, and the dark rocks are only those that contain considerable iron, or those that have been coated by so-called "desert varnish," a dark substance, probably in large part manganese, which tends to cover all exposed rocks in the desert region and to give them a black color. It is from the McElmo and La Plata formations or their equivalent, the Gunnison formation,⁶² that most of the ores of radium are obtained, and one of the most productive districts lies in Paradox Valley, Colo., 15 or 20 miles east of the La Sal Mountains.

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⁶²In the region between Denver and Salt Lake City the formation immediately beneath the Dakota sandstone bears a number of names, which are exceedingly confusing to anyone who is unfamiliar with the rocks and their relations. Thus along the Front Range the Morrison is a well-marked formation of variegated shale and sandstone whose age is uppermost Jurassic or lowermost Cretaceous. It is a fresh-water formation and contains the remains of immense reptiles (dinosaurs).

West of the mountains a similar assemblage of fresh-water sandstones and shales lies immediately beneath the Dakota. Undoubtedly this formation is in part equivalent to the Morrison, but as it is supposed to contain lower beds than the Morrison it can not be considered exactly equivalent, so it was called the Gunnison formation.

Later, in working out the succession of formations in the San Juan Mountains in southwestern Colorado, Cross found that beds nearly equivalent to the Gunnison were greatly expanded, especially in the lower part, and he felt compelled to introduce the term McElmo for rocks of nearly the same age as the Morrison, and the term La Plata for a massive white underlying sandstone. The La Plata sandstone should perhaps be included in the Gunnison. Recent work has extended the names McElmo and La Plata northwest to Greenriver, Utah.

In spite of this confusion it seems best here to use the three terms, so the name McElmo is applied on sheets 7 and 8, although Gunnison was used on sheet 6 for rocks of about the same age. The reader should therefore remember that the Morrison, Gunnison, and McElmo include rocks that may be equivalent in age.

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The low hills of McElmo rocks seem endless, but finally they are passed, and at milepost 501 the railroad cuts through the Dakota sandstone, which dips about 30° W. Next it enters the Mancos shale, which the traveler last saw at Mack, before he entered Ruby Canyon, and the features of the surface now become more subdued and softer, and he has a better opportunity to see what surrounds him. To the north he will see the familiar Book Cliffs, but they are so far away that their character is scarcely apparent. However, they swing to the south around the great anticlinal point through which Ruby Canyon is cut, and in 15 or 20 miles they will be so near the track that they can be clearly seen.

At the place where the railroad crosses the Dakota sandstone, at milepost 501, it is within a mile of the great bend which Colorado River makes to the northwest, but despite its nearness the river lies so deep in its canyon that it is not visible from the train. Three miles beyond this point is the village of Cisco, which is one of the largest shearing and shipping points in this great sheep-herding country. One unfamiliar with this region might think that there was little or no pasturage here for even a sheep, but when rain falls the country is green with grass, and even in times of drought there are forage plants that might not be noticed by the unaccustomed eye.

After the train passes Cisco the La Sal Mountains are in plain sight, and the traveler may see the great red wall on the east and also the place where it is upturned and cut by the river between the railroad and the mountain. As scene from the train the country to the right of the La Sal Mountains is exceedingly rough and rugged, being cut into great canyons with vertical sides or left in giant blocks, also with vertical sides. In fact, the traveler is now approaching a region in which the expression of the topography is different from anything that he has yet scen, unless he is already acquainted with the country that was called by Powell the "Canyon lands." In this region Hogarth's "line of beauty" is unknown. The slopes of the hills and mountains do not show gracefully curved lines from summits to bases, but each slope forms a straight line and unites with its neighbor in an angle and not a curve. The valleys are all canyons, which either have vertical sides or sides composed of straight lines, and the intervening spurs are mesas with flat tops as shown in figure 52. A glance at the country on the right of the La Sal Mountains will show some of the angularity mentioned. This characteristic feature of the land forms is illustrated in Plate LXXXII, A, which is a view taken near Moab. It also shows some of the slender towers of rock which the traveler may see from the train.

FIGURE 52.—Angular profiles of the Plateau province.

PLATE LXXXII. A (top). PLATEAU NEAR MOAB. Some of the wonderful towers and walls that may be seen on the left from the railroad. There are no carves in this landscape, only straight lines and angles. Some of the valleys hidden in these rugged plateaus are very beautiful but difficult of access. Photograph by Whitman Cross. B (middle). SHALE BADLANDS AT FOOT OF BOOK CLIFFS. Between Cisco and Thompson, Utah the railroad winds about in shale badlands similar to those shown in this view. They are nearly barren of vegetation and to many persons seem desolate, but to the lover of nature they are wonderful exhibitions of the delicate carving that is going on during every shower. Photograph by G. it. Richardson. C (bottom). GUNNISON BUTTE. A prominent isolated butte on the bank of Green River, a few miles above the town of Green River. The butte was named in honor of Capt. Gunnison, who crossed the river at this place in 1853 while surveying for the Government a route for a Pacific railroad. Photograph by M. O. Leighton.

Although the La Sal Mountains have attracted much attention, another group of mountains, which are even more interesting, are slowly appearing above the horizon, far to the southwest. Where first seen, in the vicinity of Cisco, these mountains, named, the Henry Mountains for Joseph Henry, the first Secretary of the Smithsonian Institution at Washington, are fully 100 miles distant. They are divided into three groups—the larger group at the north and two isolated peaks farther south.⁶³ These mountains lie on the west side of Colorado River, which in this region flows in a canyon 1,000 feet deep.

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⁶³The study of the Henry Mountains in 1876 by G. K. Gilbert led to the discovery of a new type of mountain, which is indirectly of volcanic origin but is not a volcano. It is now known that the La Sal Mountains and many other similar groups in the Plateau province belong to the same class. Gilbert found that the peaks of the Henry Mountains are composed largely of hardened lava, which, when it was in a molten state, instead of ascending to the surface through some fissure in the rocks and then pouring out over the surrounding country as a lava flow, welled up in the earth's crust until it lifted the covering rocks and forced them up in a great dome. As the hardened lava is more resistant than the surrounding rock, which has been worn away, it now stands up as a mountain or a mountain range.

On account of their peculiar method of formation Gilbert proposed for them the name "laccolite" (which was afterward changed to "laccolith"), meaning stone cistern. Laccoliths are not only recognized in the western country, but since they were described by Gilbert they have been recognized in almost every continent on the globe. A mountain group that has been carved from a laccolith is represented in figure 53.

FIGURE 53.—Mountains carved from a laccolith. The block at the rear shows the former position of the sedimentary beds after they were forced upward by the intrusion of the lava.

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