Exploration of the Colorado River of the West and Its Tributaries Explored in 1869, 1870, 1871, and 1872, Under the Direction of the Secretary of the Smithsonian Institution.

Page 198, Exploration of the Colorado River

198 EXPLORATION OF THE CANONS OF THE COLORADO. who first studied this region, in his report on the geology of the country ^hich he visited, says: "Having this question constantly in raind, and examining, with all possible care, the structure of the great canons which we entered, I everywhere found evidence of the exclusive action of water in their formation. The opposite sides of the deepest chasm showed perfect correspondence of stratification, conforming to the general dip, and nowhere displacement; and the bottom rock, so often dry and bare, was perhaps deeply eroded, but continuous* from side to side, a portion of the yet undivided series lying below." Professor Newberry saw the great canon region which I have described only on its southern border, but where the canon features are developed on the grandest scale. My own observations overlap his, and extend to the north many hundreds of miles; and during the last six years I have explored many thousands of miles of canons, and everywhere the facts observed confirm Professor Newberry's conclusions, as stated above. Though the entire region has been folded and faulted on a grand scale, these displacements have never determined the course of the streams. The canons are seen to cut across them, either directly or obliquely, here and there, and in a few instances, I have observed canons to follow the course of faults for a short distance. They have also been observed to run back and forth across a fault; but such instances are surprisingly rare. In all the canons where the streams are not so large as to cover the bottom, the continuity of the strata below has been apparent; and in the canons traversed by the larger streams, the beds on either side have been found at the same altitude; and if it is supposed that these water-ways were determined by fissures, then such fissures were made without displacement, and did not extend to the depths now reached by the streams. If it is possible to conceive of such fissures, they must have been quite narrow; in fact, the whole supposition is evidently absurd. All the facts concerning the relation of the water-ways of this region to the mountains, hills, canons, and cliffs, lead to the inevitable conclusion that the system of drainage was determined antecedent to the faulting, and folding, and erosion, which are observed, and antecedent, also, to the formation of the eruptive beds and cones.