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

As the train leaves the station at Canon City the traveler in the open-top car is prepared to see and enjoy to the utmost the magnificent spectacle of the Royal Gorge. This gorge, however, forms only a small part, as measured in miles, of the grand canyon of the Arkansas, which stretches from a point a mile west of Canon City westward to a point about 3 miles beyond the small village of Cotopaxi, a distance of 34 miles.

On leaving the station the traveler sees on the south (left) the station which marks the end of this branch of the Santa Fe Railway. He is now at the place where the great railroad war was waged from 1876 to 1879, and after seeing the canyon he will understand fully that it is hardly possible for two roads to occupy this narrow gash in the rocks, and consequently each road made its supreme endeavor to be first to build through the canyon. In the 40 years that this road has been in operation thousands of travelers from all parts of the world have passed through the gorge and have admired its awful grandeur.

About a mile from the station the traveler may see on the north (right) the State penitentiary with its well-kept grounds, at the extreme farthest point of which is Iron Spring, one of the attractive features of Canon City. The pavilion that covers the spring may be seen on the right, and just opposite is the power plant, which at times fills the beautiful clear air with a dense pall of smoke. This dense cloud of black smoke should not be permitted, for when the wind is from the east it drifts up the track and conceals much of the beauty of the Royal Gorge. The rocky ledge that is exposed a few feet beyond the spring is the Dakota sandstone, which marks the base of the Upper Cretaceous series. This sandstone is the most resistant bed in the series of rocks here upturned, and it therefore stands up as a sharp-crested ridge or hogback, which extends for a long distance across the valley parallel with the mountain front. About 2 miles south of the river there is a great break (fault) in the beds of rock, separating those of the mountains from those of the plains, and the Dakota hogback ends against this fault. Along the summit of the hogback, which in places is wide enough only for a road, the famous Skyline Drive (shown in Pl. XXXV) has been constructed.

From the Dakota sandstone to the mountain front the beds are all steeply upturned, but their position can not be made out very well from the train. These beds of sandstone and limestone once doubtless extended at least as far west as Parkdale, and when the mountain was uplifted they were bowed up in a great curve, as suggested in figure 16 (p. 80), but the streams cut into these uplifted rocks very actively and in course of time removed them and even cut down hundreds of feet into the massive granite on which they rest. The first formation below the Dakota is the Morrison, which forms the west side of the hogback. It consists of variegated shale and sandstone, in which green and red beds predominate. It is in this formation that the bones of the giant reptile described on page 70 and shown in Plate XXXII, A, were found.

West of the outcrop of the Morrison lies a red sandstone that is in places at least a thousand feet thick. This sandstone is particularly prominent about Manitou, in the valley of Fountain Creek, and for this reason is called the Fountain formation. This sandstone is of middle Carboniferous (Pennsylvanian) age. A limestone or a and pink dolomite²⁴ about 100 feet thick and a sandstone of about the same thickness lie below the Fountain formation. This sandstone rests on the granite of the Front Range. All the rocks below the Dakota sandstone are prevailingly red, and this color is well displayed in the valley west of the hogback.

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²⁴A dolomite is generally regarded as a limestone, but a limestone consists essentially of carbonate of lime, and a dolomite of double carbonate of lime and magnesia, containing 55 to 65 per cent of carbonate of lime and 35 to 45 per cent of carbonate of magnesia.

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At Burnito siding may be seen some of the canals that carry water to irrigate the valley below, as well as the pipe line which supplies Canon City with water. The pipe line is high up on the north (right), and the water is carried by gravity into a settling reservoir, which may be seen on a hill to the right. Below the city aqueduct is a canal, which is taken by a tunnel through the hogback to irrigate the orchards on the north side of the valley. On the south there are two canals, one high up on the hillside and one near the level of the river bottom. The higher canal receives its water from Grape Creek, which enters the river just at the edge of the mountain; the lower one takes water from Arkansas River near the mouth of this creek.

A short distance above Burnito siding the traveler is face to face with the imposing portal of the Royal Gorge. (See Pl. XXXIII, B.) On the left is the old Hot Springs Hotel, now abandoned, and on the right and considerably above the railroad are some small tunnels through which the city pipe line is carried. The passage seems almost barred by the great slab of gneiss which projects from the north and stands 400 or 500 feet high. The traveler may imagine that the train will at once plunge into the shadowy depths of the mighty gorge, but after passing the portal he finds that the canyon, though rocky, is not particularly rugged or precipitous.

The observant traveler will soon notice that there is close connection between the character of the rock and the shape and narrowness of the gorge. Where the rock is massive granite cut by few joint planes the gorge is narrow, but where the rock is intricately banded and composed of many layers of diverse appearing rocks it is wider and the slopes are more gentle. The differences in the form and width of the canyon are due to differences in the resistance which the various kinds of rock have offered to the cutting power of the stream and to the processes of weathering.

Although the rocks throughout the Royal Gorge are in general similar, they differ greatly from place to place, their character depending largely on the crushing stresses to which they have been subjected at great depths in the earth. In some places the rock is massive granite; it has never been crushed or disturbed in any way. In other places the rock (probably originally granite, or possibly sandstone and shale) has been so squeezed and crushed that it has been more or less changed. The minerals of the rock have been recrystallized, and in the process of change the crystals have been arranged in layers at right angles to the direction in which the force was applied, and the rock has become a gneiss. In some places the process has been carried so far that all the rock material has been recrystallized, and the rock has become an exceedingly soft mica schist, composed largely of small flakes of mica, and it can be split like a slate. The structure is complicated also by dikes, which cut across the other rocks, or irregular intrusive masses which here and there break up the regularity of the banding. In places veins of quartz have been deposited from mineral-bearing waters that slowly circulated through open fissures. Finally all these masses have been turned and twisted, folded back upon themselves, and broken, until the result is a structure which is complicated almost beyond description.

As the train moves on the canyon walls grow higher and some what steeper, and through a side gulch here and there the traveler may catch glimpses of the most rugged towering pinnacles. Such a view may be obtained about half a mile above milepost 164, up a small canyon on the right to a wall of massive granite that stands at least 1,000 feet high.

At the abandoned station of Gorge the Royal Gorge really begins. Below this point the railroad has had little difficulty in finding a passage, but immediately above the old station the walls close in until the stream has a width of barely 50 feet. The walls are massive and rise nearly vertically to heights of 1,000 to 1,200 feet. (See Pls. XXXVI, A, and XXXVII.) The train here plunges into the vast depths of this narrow cleft, and the traveler is free to enjoy the scene, without a thought as to how or where he is to emerge from them. He knows that he will be through the canyon in a few minutes, but the early explorers had no such knowledge. Lieut. Pike, who visited the Royal Gorge about the first of January, 1807, had serious difficulty in exploring its narrowest parts. Can anything more difficult be imagined than that attempt to find a passage through this unexplored gorge at a time of the year when the water was ice-cold?

PLATE XXXVI. A (left). MASSIVE WALLS OF THE ROYAL GORGE. View up the canyon from the train near the old station of Gorge. The massive wall on the right is shown also in Plate XXXVIII. The water pipe to Canyon City tunnels the projecting point on the left. Photograph by Marius R. Campbell. B (middle). FOREST OF LODGEPOLE PINE. This tree grows remarkably straight and tapers from base to top. In a mature forest few trees exceed 12 inches in diameter. The young trees are prized by Indians for tepee or lodge poles. Photograph by U. S. Forest Service. C (right), GRAND CANYON OF THE ARKANSAS. Projecting point on the south wall above Cotopaxi and the new Rainbow Highway at the base of the cliff. Photograph by Marius R. Campbell.

PLATE XXXVII. VIEW LOOKING DOWN INTO THE ROYAL GORGE. When one stands on the rim above the old station of Gorge and looks down into this great chasm the railroad looks like a thread stretched beside the foaming stream. The point of the rim ordinarily reached by travelers is around the bend to the right. The lowland in the distance is at Parkdale, and the gap in the range beyond is the mouth of the river canyon that extends upstream to Cotopaxi. Photograph furnished by the Denver & Rio Grande Western Railroad.

At Gorge the Canon City pipe line crosses the river. In rounding the next point on the right the traveler may see above him one of the most massive walls in the canyon. It is probably 1,200 feet high and is nearly smooth as far as one can see. After passing around this projecting mass into the next bend the traveler on looking ahead may see people on the crest of the wall, for the automobile road from Canon City leads to this point. The wall upon which they stand is about 1,100 feet²⁵ above the railroad, but the rock is so massive that it is difficult to appreciate its great height. At milepost 166 the traveler is directly below the point reached by the automobile road, and he may obtain some idea of the immensity of the gorge, but the view from the bottom, though interesting, does not compare in grandeur with the view to be obtained from above. One is more accustomed to looking up at great heights than to looking down into great chasms, and the canyon is therefore less striking when seen from below than from above.

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²⁵Many figures have been given for the depth of this canyon, but all appear to be only guesses. The favorite figure seems to have been 2,000 feet, or approximately half a mile. The writer, believing that the public is entitled to know the truth about such striking scenic features, requested that the height of the cliff be determined. Accordingly, D. E. Winchester, of the United States Geological Survey, with telescopic alidade and planetable, measured the vertical distance from the base to the top of the cliff and found it to be approximately 1,100 feet. This measurement may be in error as much as 4 feet but probably not more than that.

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The train swings around the base of the overhanging walls of the point on the right and crosses the Hanging Bridge (Pl. XXXVIII) in the narrowest part of the gorge. In places here the walls actually overhang, but pictures of the gorge taken from this point have been so widely circulated that almost everyone, even before reaching Colorado, is familiar with them. The engineering feat of hanging a bridge from the walls of the canyon instead of supporting it by abutments is of course novel and attracts much attention, but few who pass over the road think of the engineers who made the first location for the road or of the workmen who hewed their way through the solid rock. It is reported that at some of the construction camps men and tools and mules and carts were let down the canyon wall by ropes; that the engineers made their locations on the ice or while struggling through the icy waters; and that the rockmen were hung suspended in the air while they drilled the holes in the granite and fired the blasts that sent tons upon tons of rock crashing into the stream below. If the experiences of these men could be written the story would abound in thrilling moments of suspense and hairbreadth escapes that would rival the scenes shown in the most realistic moving picture.

PLATE XXXVIII. HANGING BRIDGE, ROYAL GORGE. The Hanging Bridge, in the narrowest part of the canyon, is a striking feature. When the road was built there was not room at this point for both river and railroad side by side, so a bridge was necessary. The easiest way to construct such a bridge was to use the two walls of the canyon as abutments and to swing the bridge from trusses, as shown in this view. The joints in the granite are nearly vertical, and consequently the walls have little backward slope. Photograph furnished by the Denver & Rio Grande Western Railroad.

As already stated, the narrower and more rugged parts of the Royal Gorge are cut in the harder rocks. This fact is well illustrated near the Hanging Bridge, for here the walls are vertical because the great joint cracks that cut the granite are vertical. Whenever a piece of rock is split from the walls it breaks off along one of these vertical joints, and the stream has difficulty in undermining a wall that is composed of huge blocks of rock set on end or rather that have one end deeply buried below water level. The great open fissures along some of these joints give picturesque detail to the walls; the best known fissure is one on the right that can be seen to advantage by looking back just after passing the Hanging Bridge. This crack is 20 feet wide, and down it flows a stream of water which in the driest season yields cool water to the thirsty traveler who may be enjoying a tramp through this great highway. The traveler will doubtless see many other cracks almost as strongly marked as this one at different places in the canyon walls. Many of these fissures have been cleaned out by small streams of water, leaving crevices only a few feet wide, which in many places slope under the overhanging rock for long distances.²⁶

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²⁶Doubtless many persons who have passed through the Royal Gorge have wondered what agent produced this deep and narrow cleft. The question may not often have been voiced, but scarcely anyone can see a chasm so tremendous without wondering how it was formed. The answer which the traveler will get to such a question depends upon the person making the reply. If it is a geologist he will say that the river has excavated the canyon, cutting away the rock grain by grain; but if the question is answered by one who has not made a study of such problems he will probably scout such a proposition and say that it is impossible for a river to cut a hard rock like this gneiss and that the gorge is due to a great fissure that was opened by an earthquake. This view is most commonly held by those who are unfamiliar with the work of streams and was even held by many geologists less than a century ago.

It is comparatively easy to prove that the Royal Gorge was not formed by an earthquake, for, first, the gorge is too crooked to be the result of a fissure and, second, the bands of rock can be traced practically from wall to wall across the canyon. There is no possibility of a break such as would be required by the earthquake hypothesis. Altogether the evidence is conclusive that the Royal Gorge and most other canyons are not earthquake fissures but were cut by the streams that occupy them.

The cutting power of water depends on the amount of sand and gravel which the stream is able to carry or to roll along on its bottom. Clear water may dissolve the rocks, but it has no cutting power. Water loaded with sand cuts the rocks by the scouring action of the grains of sand on the rocks over which the water flows. It acts much like a sand blast, and no rock is so hard that it can withstand the constant grinding of grains of sand. According to human standards the process is very slow, but it is almost constantly in operation, day and night, and eventually it will make its work apparent.

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A short distance above the Hanging Bridge, as shown in Plate XXXIX, the walls diminish in height and the canyon opens and bears little resemblance to the narrow gorge just below. About three-quarters of a mile above milepost 166 the slopes are so gentle that they can be scaled, and a trail leading to the top turns up the slope on the north (right). In this part of the canyon the walls are not composed of massive granite or even gneiss, as at most places below, but the rock is a schist, composed largely of flakes of mica that may be recognized by the manner in which they glisten in the sunshine. This mica schist is very soft, compared with the granite and gneiss, and therefore weathers more rapidly, so that the canyon is wider and has smoother and gentler slopes.

PLATE XXXIX. UPPER END OF THE ROYAL GORGE. The traveler on the rim of the canyon can climb down, if he has a steady head, to the jagged point shown on the left. Here he can look on the Hanging Bridge and the railroad trains as they thunder through the canyon, waking the echoes from every angle of its mighty walls. The rocks here are much more highly jointed than they are lower down, and as a result the canyon walls begin to have an appreciable slope and to decrease in height. Photograph furnished by the Denver & Rio Grande Western Railroad.

Just beyond milepost 168 are the headgate and settling tanks of the Canon City waterworks. In this vicinity the gray granite is cut by a great many dikes of pink feldspar (pegmatite). The crystals of feldspar are large, and their brilliant faces attract attention, especially when the sun is shining on them. In some places these dikes are so numerous and so large that they make up the bulk of the rock and give it a strong red color. The pink feldspar is very abundant in the rock from the siding called Sample to the edge of Webster Park, near Parkdale,

Toward the west the hills grow smaller and the canyon less pronounced, until finally, in making a sharp turn to the right just before reaching milepost 170, the traveler catches on the left a glimpse of an open valley of considerable extent, which comes as a pleasing contrast to the frowning walls of the deep canyon. This open valley is Webster Park, one of the beautiful natural parks which diversify the mountain scenery of Colorado. The surface of Webster Park is underlain by soft sedimentary rocks that have been downfolded or dropped by some fault, thus being preserved from complete destruction by erosion.

The first sedimentary rocks that can be seen from the train are on the right. They are the variegated shale and sandstone of the Morrison formation, and above them lie the more somber sandstones of the Dakota. These beds of rock lie nearly horizontal, but doubtless their contact with the granite, if it could be seen, would show that they rise gently toward the east at about the same rate as the surface of the granite on which they were deposited. The traveler may be surprised to find the Morrison formation in Webster Park in contact with the granite, whereas at Canon City several hundred feet of beds lie between the Morrison and the granite. The absence of these underlying formations in Webster Park is probably due to the fact that the upper surface of the granite was for a long time a land surface and upon this land the sedimentary beds were deposited at different elevations before the granite was arched and broken by faults, as shown in figure 16. Thus the lowermost formation at Canon City may have originally extended onto the granite a mile or so and the next one 2 or 3 miles, and so on, until finally, when the Morrison was deposited, the entire area was low, and the Morrison beds were laid down continuously from Canon City to Parkdale.

FIGURE 16.—Section from Canyon City to Parkdale showing former extent of the Dakota and Morrison formations and the pinching out westward of the lower formations. There are two faults near Parkdale, as shown.

West of milepost 170 the beds dip sharply toward the west, as shown in figure 16, and the Dakota disappears under the dark shale of the Benton. About 1,500 feet beyond milepost 170 the shale is in contact with the granite, which shows that they must have been brought into this abnormal relation by a fault that dropped the shale on the east as compared with the granite on the west. This relation of the shale and the granite is illustrated in figure 16,

Beyond this fault the hill on the north (right) of the railroad is composed entirely of granite, but on the south the variegated shale of the Morrison rests on the granite just as it was deposited ages ago. At the point where the railroad crosses Tallahassee Creek the Morrison outcrop swings to the north, and a hill composed of this formation, capped by Dakota sandstone, which dips toward the west, may be seen half a mile away. The sedimentary rocks can not continue in this direction much farther, for the granite, which can be seen on the north, makes a high rim completely around the valley.

The rock in the middle of the valley is concealed by a deep cover of gravel, which the river has evidently brought down from the high mountains farther west. One of the striking features of this gravel-covered terrace is the great number of big boulders that litter the ground around the station at Parkdale and for some distance to the east. These boulders are composed of all sorts of rock from the high mountains and range from mere gravel stones of the size of a marble up to boulders 10 or 12 feet in diameter. These large boulders have certainly been brought down the river valley, but by what agency? Could water have transported them? At first sight it would seem impossible for water to move boulders of this size through a canyon and then spread them out in a great fan nearly a mile long, but there seems to be no other agent by which they could have been transported. Some may suggest that possibly the glaciers of the Ice Age may have extended down as far as Parkdale and carried the boulders and dropped them where the ice melted. It is well known that glaciers do carry such boulders, but a glance at the rugged walls of the canyon above Parkdale (see Pl. XL, A) will soon convince the traveler that no glacier has ever moved down this canyon. Water, therefore, is apparently the only agent that could have transported these boulders.

PLATE XL. A (top). GRAND CANYON OF THE ARKANSAS BELOW TEXAS CREEK. Below Texas Creek the canyon in many places is very rough and rugged, the massive granite projecting from the walls on either side seems almost to bar the pathway of the river, and these spurs are crowned with crags and pinnacles. Photograph by Macins R. Campbell. B (bottom). TUNNEL ON RAINBOW HIGHWAY. The construction of the Rainbow Highway involved engineering difficulties as great as those which beset the railroad engineers in 1881. Much rock cutting was done, and even tunnels were driven through the projecting points of massive granite. Photograph by Marius R. Campbell.

Just as the train emerges from the canyon into Webster Park it crosses the Rainbow automobile road, which was last seen at Canon City. It was manifestly impossible for this road to follow the river through the Royal Gorge, so it takes a more circuitous route to the north and then returns to the river in Webster Park. Here it crosses to the south side of the river and follows that side until the river emerges into the broad valley at the foot of the Sangre de Cristo Range²⁶ above Cotopaxi. The construction of this road through the canyon above Parkdale involved a large amount of rock work, and the State and county deserve to be congratulated on its completion. (See Pls. XXXVI, C; XL, B; and XLI, B.)

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²⁶Spanish term meaning "blood of Christ," pronounced sahn'gray day cris'to.

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PLATE XLI. A (top). GOLD DREDGING. Great dredges like those used in deepening harbors and in excavating the Panama Canal are set to work in the heart of the Rocky Mountains, digging up annul washing gravel for the gold it contains. This view shows the great heap of washed gravel that is left in the wake of the dredge. Photograph by F. L. Ransome. B (bottom). RAINBOW HIGHWAY. Automobiles now traverse the grand canyon of the Arkansas as readily as railroad trains, owing to the recent completion of the Rainbow Highway from Parkdale to Leadville. In many places the cost of construction was as great as that of the railroad on the opposite hank. Photograph by the U. S. Forest Service.

Webster Park is an oasis of valley land in a wilderness of mountains. Near the river some of the soil is too gravelly for farming, but back from the river there are good farms. Stock raising is the principal occupation, and the cattle find good summer pasture upon the mountain slopes. At the station of Parkdale the traveler, on looking back, can see the low range of mountains, or rather the plateau, in which the Royal Gorge is cut.

About Parkdale the dark shale of the Benton shows in a number of places below the gravel, and the next rock that is seen in passing westward is the granite at the mouth of the canyon. It is therefore certain that no hard rocks, such as the Dakota sandstone, are present between the Benton shale and the granite, and the shale and the granite must be brought into contact by a fault, as shown in figure 16.

Above Parkdale the river is again confined in a narrow, rugged canyon, which has been cut in a plateau similar to that in which the Royal Gorge is cut. (See Pl. XXXIV, A, p. 72.) Upon this plateau there are several ranges of mountains, which rise to elevations of 12,000 to 14,000 feet above sea level and which are included in the San Isabel National Forest. This forest furnishes excellent summer pasture for a large number of cattle and sheep, which are driven into the mountains each spring from ranches in the lowland on both the east and the west. The forest is also an effective conserver of water, for in it lie the heads of a number of streams that supply water for domestic use and irrigation to the cities, towns, and ranches of the plains. It is a haven of refuge for wild animals, particularly deer, which thrive upon its excellent pasture lands. The fawns are almost as tame as the lambs which gambol about their mothers in the deep grass. (See Pl. XLII, B.)

PLATE XLII. A (top). SUMMER HOME IN A NATIONAL FOREST. The United States Forest Service leases ground, under certain restrictions, for summer homes in the national forests. This is such a home in the San Isabel Forest, south of Arkansas River. Photograph by the U. S. Forest Service. B (bottom). GAME IN A NATIONAL FOREST. Deer soon become plentiful when they are protected. The wild fawn shown here was photographed in the San Isabel National Forest by the U. S. Forest Service.

In the Greenhorn Mountains many summer homes have been built by the citizens of Pueblo and connected with that city by fine automobile roads. The use of the national forests for recreation is encouraged by the Government, and in many localities sites suitable for summer homes have been mapped and laid off in lots so as to be available to those who wish to avoid the crowded cities during the heat of summer. The charge for building permits ranges from $10 to $25 a year, depending on the accessibility and attractiveness of the site. Logs and poles for building and wood for fuel may be procured free of charge under permit from the local forest officers. One of these summer homes is shown in Plate XLII, A.

The canyon above Parkdale, although it is generally considered with the Royal Gorge as constituting the grand canyon of the Arkansas, is really a separate canyon. It has a length of about 24 miles, measured along the railroad, and may be divided, according to its width and the ruggedness of its walls, into three parts, two of them narrow and rugged and the third, separating the more rugged parts, broad and more or less smooth.

The first part of the canyon extends from Parkdale to Texas Creek, a distance of 11 miles. This canyon is not so narrow nor so deep as the Royal Gorge, but it is nevertheless picturesque and well worthy of close attention, particularly as it can generally be seen from an open observation car. The charm of this canyon is the variety of its scenery. In places it is narrow and has steep and rugged walls; in others it is relatively broad, though here and there projecting points of rock have been cut by the stream into nearly vertical cliffs. In other words, this canyon looks as if it had been occupied by the stream for a longer time than the Royal Gorge.²⁷

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²⁷Geologists generally classify the surface features of the earth according to their age or according to the length of time they have been in the process of formation. Thus there may be young mountains and old mountains, young valleys and old valleys, and young streams and old streams, Where the rocks are fairly uniform throughout, the youngest type of valley is the canyon and the oldest is the broad valley with slopes so gentle that it almost resembles a plain. A canyon is considered young because it marks the first stage in valley cutting; a broad valley is considered old because it marks its last stage. Although all canyons are young, they may differ considerably in age, so there are young canyons and old canyons. In canyons of these two classes that are cut in essentially the same rocks young canyons may be distinguished by the narrowness of the bottoms, which are generally but little wider than the channel of the stream, and by having walls that are commonly steep and in many places precipitous. Old canyons, on the other hand, are generally wide enough, at least in places, to have narrow strips of flood plain; their walls are less precipitous, and their rocks are generally more irregular in outline Owing to the fact that they have been longer exposed to the weather.

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The walls of the canyon from its mouth just above Parkdale to Texas Creek are generally uniform in height, so that this canyon also appears to have been cut in a plateau, the surface of which was originally gently rolling. At Texas Creek a branch of the railroad turns to the south (left), crosses the river, and after running up a small valley for a short distance in order to obtain grade, turns back and loops around a projecting spur considerably above the bottom of the valley. After passing this spur the road follows for a long distance the valley of Texas Creek on its way to the mining district of Westcliffe, 25 miles distant.

Near the station of Texas Creek the canyon takes on a different aspect. It becomes much broader than it is east of that place, and though the walls may in places be precipitous, they are generally smoother and gentler in their slope than they are farther east. This part of the canyon looks older than the part below, and it is also different from the part above. On leaving Texas Creek the train heads directly toward the great Sangre de Cristo Range (Pl. XLIII) and at a point 3 miles above Texas Creek swings abruptly to the right, following Arkansas River, which here leaves the broad valley in which it has been flowing, and in a short distance it again enters a canyon, some parts of which are steep and narrow. If the traveler looks to the left as the turn is made he will see that the broad valley continues directly toward the high mountain peaks but is occupied only by Oak Creek, a stream not at all commensurate in size with that of the valley which it occupies. The meaning of these differences in the character of the canyon of the Arkansas is not yet understood, but it could probably be satisfactorily explained if the history of the river were thoroughly known.

PLATE XLIII. HOWARD AND THE SANGRE DE CRISTO MOUNTAINS. From Howard there is a magnificent view of the Sangre de Cristo Range, especially when the mountain tops are covered with snow. The highest point in this part of the range is Hunts Peak, 12,440 feet above sea level, which shows at the right of the picture. The valley was once deeply filled with gravel from the mountains, remnants of which can be seen in the long terrace on the farther side of the river. Photograph by Henry R. Hay, Salida.

Above the mouth of Oak Creek the canyon of the Arkansas for some distance is irregular in width and the sides are low, indicating considerable age, though it is generally narrow, and farther on it becomes more precipitous, until in the vicinity of Cotopaxi it is a veritable canyon, though it is wider than the part of the canyon below Texas Creek.