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Show 144 GEOLOGY OF THE HIGH PLATEACTS composed almost wholly of Carboniferous strata, bent and faulted after the manner peculiar to the Basin Ranges. Although yielding characteristic fossils, none of these Carboniferous exposures present sufficient materials for special study. The great fields of Carboniferous rocks are found in the Kaibabs to the southward and in the basin to the westward. THE SHINARUMP. Resting everywhere upon the Carboniferous of the Plateau Country is a series of sandy shales, which in some respects are the most extraordinary group of strata in the West, and perhaps the most extraordinary in the world. To the eye they are a never-failing source of wonder. There are especially three characteristics, either one of which would render them in the highest degree conspicuous, curious, and entertaining. First may be mentioned the constancy with which the component members of the series preserve their characters throughout the entire province. Wherever their proper horizon is exposed they are always disclosed, and the same well-known features are presented in Southwestern Utah, in Central Utah, around the junction of the Grand and Green, in the San Rafael Swell, and at the base of the Uinta Mountains. As we pass from one of these localities to another, not a line seems to have disappeared nor a color to have deepened or paled. So strongly emphasized are the superficial aspects of the beds and so persistently are they maintained, that only careful measurement and inspection of each constituent seam can impair the prima facie conviction that these widely-separated exposures are absolutely identical. Detailed examination, however, does show some variation in thickness and slight changes in the constituent members; but, on the whole, the constancy is, so far as known to me, without a parallel in any formation in any other region. The sculptured cliffs of the Shinarump reveal the edges of the component layers as rigorously parallel as if a skillful stonemason had laid them down, and narrow bands can be followed for miles without any visible change in their aspect. A second striking feature is the powerful coloring of some of the beds. With the exception of the dark, iron-gray shales of the Cretaceous, the tints of the other formations are usually bright, lively, and often extremely deli- |