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Show 172 GEOLOGY OF THE HIGH PLATEAUS. which reach higher altitudes than any other summits in Utah excepting a few in the Uintas. There are three points which reach above 12,000 feet, viz: Delano, 12,160 feet; Belknap, 12,080 feet, and Baldy, 12,000 ©feet. There is nothing in the aspect of this portion of the Tushar mass to suggest to the eye a plateau structure; on the contrary, the appearance is in a high degree sierra-like, and it is quite possible that this portion of it should be regarded as belonging rather to the basin than to the plateau type of uplift. But so far as the structure depends upon vertical displacement, it is much obscured by the enormous series of volcanic floods which have been poured over it by numberless eruptions. Frequent indications, however, are seen of a general and moderate dip of the whole series to the west, leading to a presumption that the whole Tushar mass has a tilt in that direction. But while the exposures are numerous, there are no extended ones among them. The process of erosion has here wrought out a sculpture differing utterly from that presented by the sedimentaries, and one calculated to conceal the frame-work of the mountains instead of laying it bare. The degradation has here been very great; greater certainly than in some of the other volcanic plateaus. Instead of great cliffs, we find only slopes covered with debris and soil, with here and there a projecting ledge, which is soon lost beneath a talus. The best exposures are seen along the eastern front, facing the Sevier Valley, and in the deep gorges opening into it and heading far back in the heart of the range. These all concur in indicating a general slope of the beds to the westward, which is strongest near the eastern flank and smaller in the central portions and western flank. The northern portion is also deeply scored with grand ravines, well calculated to kindle the enthusiasm of the mountaineer and task his energy. The exposures which they contain, so far as they have been examined, accord with those in the eastern gorges in presenting a westward inclination. It is quite possible that many faults complicating the structure have escaped detection, but it is not probable that any subordinate displacements yet to be discovered will seriously impair the conclusion adopted regarding the general structure. But while the plan of the entire uplift seems to be most nearly allied to the plateau type, it is equally apparent that there is a strong tendency |
