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

SHEET No. 7 (click on image for an enlargement in a new window)

In general the canyon grows deeper downstream, and at Escalante siding, milepost 385 (see sheet 7, p. 198), the second member of the Gunnison formation—a hard sandstone—appears near the railroad grade. Within a short distance it rises above the grade, and below it may be seen a dark shale. This shale also rises downstream, and at milepost 388 the top of a brick-red massive sandstone (Triassic) appears beneath it on the opposite side of the valley. Wherever it is exposed this sandstone; on account of its deep and uniform color and its massiveness, is the dominating feature of the canyon. As the rocks dip toward the northeast (see Pl. LXXVI, A) and as the general course of the stream and of the railroad is toward the northwest, the rocks exposed on the two sides of the canyon are not necessarily the same. Even if the stream followed a straight course the beds at the same level on its opposite sides in the same stretch would be different, but the difference is greatly exaggerated because the stream swings from side to side in great meanders. At many places a point on the outermost part of a bend to the left is more than a mile from the outermost part of the next bend to the right. The farther the stream swings to the left the lower or older are the rocks in the canyon walls, and the farther it swings in the opposite direction the higher or younger are the rocks in the walls.

Wherever the brick-red sandstone rises 100 feet or more above the water there is an inner box canyon with vertical walls, but where this sandstone is below the water the canyon walls recede by slopes and terraces. This compound character of the canyon is shown in Plate LXXVI, A. At milepost 400, 2 miles beyond Bridgeport siding, the railroad enters a tunnel that is excavated entirely in the massive brick-red sandstone, which is ideal material in which to drive a tunnel, for the roof needs no timber to support it, and the portals are equally durable. This tunnel is 2,256 feet long—nearly half a mile.

In places the walls of the canyon are about 500 feet high, but they lack both the ruggedness and the regularity that characterize the other great canyons on this route. Finally they begin to decrease in height, until, half a mile beyond milepost 410, the traveler begins to see open country, and soon he finds himself back in the same shale valley that he left a few miles below Delta. A mile farther along the train reaches the station in the small village of Whitewater. Here Grand Mesa looms up on the right as the most conspicuous feature in the landscape. On leaving Whitewater the railroad again enters the canyon, which, however, is nowhere so deep nor so interesting as it is farther up. Its walls are composed entirely of rocks of the Gunnison formation, or of rocks lying above it, and at no place does the brick-red sandstone again make its appearance. The river meanders broadly, swinging first to one side and then to the other in sharp curves which make the mileage of the railroad much more than it would be if the course were fairly straight.

As meanders like those in which the Gunnison flows in this canyon could not have been begun while the river was cutting the canyon they must have been there before the canyon was cut, and as geologists are agreed that such meanders can be formed only by a sluggish stream, the Gunnison of the time when these meanders were young was not so rapid as it is to-day; it was a lazy river that flowed slowly and wound about in the broad valley in which it was flowing. The meanders were therefore formed when this part of the country was essentially a shale plain, above which only here and there mountains lifted their heads. As already stated, such a plain is supposed to have been in existence when the lava that now caps Grand Mesa was poured out, so that the meanders which the traveler sees to-day in the river were probably formed when it was flowing at a level a mile higher than it is now, before any of the sandstones that now form the walls of its canyons were exposed. According to this interpretation the meanders are very old and are simply inherited from the former channel of the river.

Near milepost 420 the Gunnison formation disappears, below the river, and from this point down to the junction of Gunnison River with Colorado River it appears only in places, and the canyon is cut mainly in the sandstone, shale, and coal beds of the lower Mancos. The height of the walls also declines, and finally, after skirting the bluff on the right for a considerable distance, the train passes through a small cut and crosses the bridge spanning Colorado River and is soon at the station in Grand Junction.

Grand Junction is one of the largest towns of western Colorado. It stands at the junction of the main line of the Denver & Rio Grande Western Railroad and the line over Marshall Pass, on the flat plain at the junction of Gunnison and Colorado rivers, and is therefore on the natural route of railroad travel. Colorado River especially carries a large volume of water, and as its fall above Grand Junction is considerable it affords an excellent supply of water for irrigation. Water has been taken from the river for this purpose by many private companies, but generally it has been taken out only a short distance above the land to be irrigated, and consequently it has neither sufficient head nor volume to irrigate all the land adjacent to the town. Recently the United States Reclamation Service has dammed Colorado River 20 miles above Grand Junction and is carrying the water in the High Line canal (see p. 152) to the terrace or bench land back from the river and near the foot of the Book Cliffs.

Grand Junction is the center of a great fruit-growing country that extends up Colorado River nearly to De Beque, up the Gunnison a short distance, and down Colorado River to Fruita and Loma. Apples, pears, and peaches are the principal fruits raised. Views of the orchards and the method of irrigating them are shown in Plate LXXVII, A, B. Besides fruits the valley produces vegetables, principally sugar beets and potatoes. Sugar beets find a ready market at the sugar factory at this place, and many beets are shipped here from other parts of the two valleys.

PLATE LXXVII.A (top). TWO CROPS ON IRRIGATED GROUND. In the irrigated districts land and water are made to do double duty by providing a crop of small fruit or vegetables between the rows of fruit trees. Photograph furnished by the Denver & Rio Grande Western Railroad. B (bottom). METHOD OF IRRIGATING ORCHARDS. Great care and judgment are required in properly irrigating growing fruit trees. This view shows how the water is conducted to all parts of the orchard and controlled in its flow so as to get the best results. Photograph furnished by the Denver & Rio Grande Western Railroad.

The town has broad, well-paved streets, good business houses, and a very attractive residence section, whose streets are well shaded by trees that afford relief from the rays of the sun. These trees, together with the orchards, make this part of the valley look like an oasis in a desert. A description of the scenery along the main line east of this place ends on page 158.