LITHOLOGICAL CHARACTERS OF THE MESOZOTC. 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 carving's 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 fashions — its own school of natural 

 architecture. The Gray Cliffs, the Vermilion Cliffs, the Shinarump (Lower 

 Trias) — each has its own topography, and they are as distinctly individu- 

 alized 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 



