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Show LITHOLOGICAL CHARACTERS OF THE MESOZOIC. 207 ceous. Quite as strongly individualized are the topographical features which have been sculptured out of them. The great marvels of surface sculpture found throughout the lower Plateau Province, the grand cliffs with strange carvings and elaborate ornamentation, the wonderful buttes and towering domes, the numberless shapes which startle us by their grotesqueness owe their peculiarities as much to the nature of the rocks themselves as to the abnormal meteoric conditions under which they were produced. Each formation has its own fashionsâ€"its own school of natural architecture. The Gray Cliffs, the Vermilion Cliffs, the Shinarump (Lower Trias)â€"each has its own topography, and they are as distinctly individualized as the modes of building and ornamentation found among distinct races of men. The uppermost member of the Jurassic series is fossiliferous, and has yielded a fauna which, though not very abundant, is still highly characteristic and sufficient to fix its age with certainty as Upper Jurassic. Immediately below it is the Gray Cliff sandstone, so wonderful for its cross-bedding, for the massiveness and homogeneity of its stratification, and for its persistence without any notable change of character over great areas. This formation has been assigned to the Jurassic solely on the ground of its infra-position to the fossiliferous member just mentioned. The Gray Cliffs have not yielded a solitary fossil hitherto of any kind. Next below is the Vermilion Cliff series, characterized by beds of sandstone built up in many layers, with a tendency towards shaly characters, though seldom or never a true shale. It is as persistent as the Gray Cliffs above, and in color it contrasts powerfully with it. The Gray Cliffs are nearly white, and are merely toned with gray; the Vermilion Cliffs are intensely, gorgeously red. The latter also is destitute of fossils, except a few obscure fish-scales, though great search has been made for them. Beneath lies the Shinarump. It consists of a very remarkable conglomerate above and a series of shales below. The conglomerate is made up chiefly of fragments of silicified wood, cemented by a light-colored matrix of sand, lime, and clay, out of which the woody fragments weather and are scattered over the plains below. The shales below consist of a succession of layers, each a few feet or a very few yards in thickness, preserving that thickness with remarkable |
