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Show 2 INTRODUCTORY. miles If we examine the old War Department maps of the western half of the United States and those maps which have been derived from them, we shall find the Wasatch Mountains laid down as extending southward with an increasing westerly trend until the range reaches a point near the southwestern corner of Utah. This delineation conveys to the eye the general truth that along this belt of country there is a lofty and, in a qualified sense, a mountainous barrier separating the drainage system of the Colorado River from that of the Great Basin of the West. It would be impracticable upon a map of small scale to designate clearly the fact that the Wasatch as a distinct mountain range ends at Mount Nebo, 75 miles south of Great Salt Lake, and that it is here overlapped en echelon by a chain of plateau uplifts which extend southward, gradually swinging around the southeastern rim of the Great Basin. These plateaus are not a part, either structurally or topographically, of the Wasatch, but belong to another age, and are totally different in their forms and geological relations. The extension of the name '•Wasatch Mountains" south of Nebo is a misnomer. The region south of that mountain has nothing in common with the belt to the-north of it, except the mere fact that it carries the boundary line between the two drainage systems; otherwise the two belts constitute one of the most decided of those strong contrasts of topography and geological relations which are sometimes presented in adjacent portions of the Rocky Mountain Region. Those who have studied these plateaus have recognized their distinct character, and it seems necessary to give effect to this recognition to the extent of employing for purposes of geological discussion a distinguishing name. It has seemed to me that for these purposes the belt of country which they occupy would be sufficiently characterized by giving to it the name of the District of the High Plateaus of Utah. These uplifts have certain analogies to mountain ranges, but in most cases are distinguished by their well-marked tabular character. component members of the groups of high plateaus. There are three ranges of plateaus within the district, and each range can be subdivided into individual tables. The westernmost range is made |
