70 GRAND CANON DISTRICT. 



and Tertiary strata which have been spared in the enormous denudation 

 which has eaten out the heart of the Plateau Province. Their presei ra- 

 tion has been largely due to extensive outpours of lavas, which have 

 overspread most of their summits, and the energy of the eroding agencies 

 has there spent itself upon the more obdurate materials of volcanic 

 origin. 



Starting from the right angle and reaching out south-southeast is 

 a rather lofty mass, named the Kaiparowits Plateau. It reaches to 

 the Colorado River, where it is cleft asunder by the mighty gorge of the 

 (ilen Cailon, but resumes its course on the other side, extending into 

 Arizona, where it spreads out. It is composed of Cretaceous strata. Its 

 western Hank forms a part of the eastern boundary of the Grand ( 'anon, 

 or more restrict edly of the Marble Cafion, district. Here again is the 

 same old arrangement — terraces with their marginal dill's rising from 

 the Carboniferous platform step by step to the Middle Cretaceous — the 

 cliffs all looking westward over the great region from which the former 

 extensions of the strata they terminate have been swept away. 



Thus we may note that the northern and eastern boundaries of the 

 Grand Cafion District are cliff-bound terraces. Crossing the district 

 either longitudinally from north to south, or transversely from east to 

 west, we find as we approach the southern or western border that the 

 Carboniferous platform ascends very gradually. There are broad and 

 feebly marked (sometimes well marked) undulations, or ups and downs; 

 but, on the whole, the country gains in altitude as we approach its 

 western and southern limits. At last it terminates in a giant wall 

 plunging down thousands of feet to the platform of a country quite sim- 

 ilar to that of the Great Basin of Nevada. Those who have traveled on 

 the Central Pacific Railway will recall the features of that very desolate 

 region which lies between Great Salt Lake and the Sierra Nevada; and 

 all those features are repeated and their desolation intensified in the 

 dreadful region which lies west and south of the Grand Cafion District. 

 The district may be conveniently divided into parts. The northern- 

 most portion is the area comprising the southern terraces of the High 

 Plateaus. A description of these sufficient for preliminary purposes has 

 already been given. At the foot of these ten aces stretches away to the 

 southward the great Carboniferous platform of the heart of the district. 

 That portion of the platform which lies north of the Colorado River may 

 be subdivided into five distinct plateaus. Naming them in regular 

 order from west to east, they are: 1, the Sheavwits; L>, the Uinkaret; 3, 

 the Kanab; 4, the Kaibab; 5, the Paria. These five plateaus are sepa- 

 rated from each other by natural boundaries, which are for the most 

 part quite distinct. These boundaries are great faults or dislocations of 

 the main platform, which have produced cliffs by hoisting the platform 

 on one side of the fault line or dropping it on the other. To show how 

 these dislocations have affected the topography, the reader is referred 

 to the east and west section delineated in the accompanying dia- 



