Page:Popular Science Monthly Volume 7.djvu/557
PHYSICAL FEATURES OF COLORADO VALLEY.
course, and runs into a fold, which has a northeast and southwest axis, but its central line is never reached. Before coming to it the river turns again to the west, and runs entirely out of the fold, at the mouth of the Dirty Devil River. It will thus be seen that the dip of the formations under discussion is to the northwest. Going down to the middle of Cataract Cañon, we constantly see rocks of lower geological position appearing at the water's edge; and, still continuing from that point to the foot of Narrow Cañon, the same beds are observed in reverse order; that is, we see at the water's edge rocks of later geological age.
Where the upturned axis of this fold is situated is not known; but, looking away to the southeast, mountains are seen—the Sierra La Sal and Sierra Abajo. Looking over the general surface of the country, it appears that the course of the river is from lower into higher lands and then back again. Observing the present topographic features of the country, it seems strange that it did not find its way directly across from the foot of Labyrinth to the foot of Narrow Cañon, following the low lands. Why should it leave this low region, and run away out into the slope of a system of mountains, and then return? We must remember that the river is older than the mountains and the cliffs. We must not think of a great district of country, over which mountains were piled, or built, or heaved up, and that when rain fell it gathered into streams along the natural depressions of such a country and thus attempt to account for the course of the river; but we must understand that the river cut its way through a region that was slowly rising above the level of the sea, and the rain washed out the valleys, and left rocks and cliffs standing, and the river never turned aside from its original course to seek an easier way, for the progress of uplifting was not greater than that of corrasion. Again we see how slowly the dry land has emerged from the sea; no great convulsion of Nature, but steady progress.
The Orange, Cliffs, which terminate Labyrinth Cañon, extend to the west a few miles, and then change their course to the southwest, running parallel with the axis of the fold we are now discussing, and they cross the Dirty Devil a few miles above its mouth. Thus they are seen, like the other lines of cliffs, to face the axis of a fold. Fig. 2 is a bird's-eye view of this country, showing the course of the river through Stillwater, Cataract, and Narrow Cañons. It represents the cutting of the stream into the slope of a mountain-range, and out of it again, without crossing the range. On the left it shows two lines of cliffs. Here we have a district inclosed within Titanic walls. On the southeast are great mountains, and from the foot of their slope, on the north side, near Grand River, we find a line of cliffs crossing this stream, and extending to the Green, in a westerly direction; then to the southwest, to the Dirty Devil River, and then broken and confused by buttes and cañon-walls, which extend toward the east, until it