CHAPTER II
THE GRAND CANYON OF THE COLORADO
Nowhere else on the face of the globe is one so vividly impressed by the vastness of the work of corrasion as in the northwestern part of Arizona. Here the mutilated breast of Mother Earth discloses a chasm from three thousand feet to seven thousand feet deep, cut through horizontal strata of sandstone, shale, limestone, and granite, chiefly by the agency of water.
This stupendous chasm is the Grand Canyon of the Colorado River. It is more than two hundred miles long; and from rim to rim its walls measure in places twenty miles across. It is not a clean-cut open channel from wall to wall, but, on the contrary, it is filled with castellated peaks, buttes, pinnacles, ridges, seams, and lesser canyons. Down deep in its lowest part, hurrying onward with impetuous speed, is the river itself.
Geologists tell us that this stream was an ancient river before the Mississippi was born and that it formerly watered a valley as fertile.
Ages ago when Time was young the river found its channel closed by an obstruction—just how, or where, or by what, no one knows. So it spread out into a great lake, or, perhaps, into an inland sea several thousand feet deep. The rock waste carried into its basin hardened into sandstone—red, pink, and white of many shades.
After this great inland sea had become dry the Colorado River was born—just how, or when, or because of what, one can only guess. But when it was born it began to undo what its predecessor had done. It cut a channel in the surface of the sandstone and then began business in earnest. It loosened little pieces of sharp flint from the sandstone and swept them along with such force that each became a tiny mallet and chisel combined to cut and carry away other rock. And so it kept on until it had carved a passage not only to the original granite bed rock but in places a thousand feet or more into it. A few localities excepted, the canyon does not form a single gash; nor has it the usual V-shape of canyons in regions of plentiful rainfall. On the contrary, its cross-section takes the form of a succession of steps and terraces, as though the river cut the channels successively in decreasing widths. And because the region through which it flows is one of very slight rainfall, all the landscape outlines are bold and sharply angular.
All told, an area comprising two hundred thousand square miles has been denuded to the depth of six hundred feet, and the material borne southward by the Colorado and its tributaries, while the land through which they flow has been literally drained to death. Even the tributaries have formed deep lateral canyons that meet the level of the main stream. It staggers the mind to try to grasp the time expressed in countless eons since the youth of this now senile river.