114 



GRAND CANON DISTRICT. 



A. 





•/. 



The brilliant red sandstones form the long curved slope which descends 

 from the plinth of cross-bedded sandstone to the plain below. 



The walls of the inner gorge have at the summit about 325 feet of hard 

 sandstone of a brown red color. Beneath the sandstone are about 1,800 

 feet of impure limestone in layers of the most massive description. Very 

 few such ponderous beds of limestone are found y & 

 in any part of the world. The color is deep 

 red with a purplish tone, but the brilliancy 

 of the coloring is notably weakened by weath- 

 ering. Still lower are red-brown sandstones r§ 

 again having a dark and strong shade and lying I 8, 

 in very massive beds. The strata forming the -=" 

 walls of the outer chasm from the summit to of 

 the plain below are designated the Aubrey |- 

 group, and this is again subdivided at the base |s. 

 of the cross-bedded plinth into Upper and 1» 

 Lower Aubrey groups. The two subdivisions »£ 

 are believed to be the equivalents, in age, of rs 1 

 the Coal Measures of Pennsylvania and Eng- | © 

 land. The strata disclosed in the inner gorge S& 

 correspond in age to the Lower Carboniferous 3-h 



of those countries 

 Red Wall group. 



and are here termed the 

 Some uncertainty exists 



5 * 



regarding the beds which lie at the base of "i< 

 the conformable series deep downin the chasm, §.f 

 but they are regarded at present as being just g ' 

 what they seem and just what they would nat- Id 

 urally be inferred to be — a part of the Car- P 

 boniferous system. Of the strata at the bot- z> 

 torn of the canon, we shall have more to say \ \ 

 hereafter. They are regarded at present as f ~ 

 being of Lower Silurian or Primordial age. 



The observer who, unfamiliar with plateau 

 scenery, stands for the first time upon the 

 brink of the inner gorge, is almost sure to 

 view his surroundings with commingled feel- 

 ings of disappointment and perplexity. The 

 fame of the chasm of the Colorado is great ; but 

 so indefinite and meager have been the descriptions of it that the imagina- 

 tion is left to its own devices in framing a mental conception of it. And 

 such subjective pictures are of course wide of the truth. When he first 

 visits it the preconceived notion is at once dissipated and the mind is 

 slow to receive a new one. The creations of his own fancy no doubt are 

 clothed with a vague grandeur and beauty, but not with the grandeur and 

 beauty of nature. When the reality is before him the impression bears 

 some analogy to that produced upon the visitor who for the first time 



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