xlii INTEODUCTION. 



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Colorado at two points on tlie route. Dr. IS'ewberry was the 

 geologist of this expedition, an account of which was published 

 by authority of Congress in 1861. This volume gives the 

 most perfect account of an exploration scientifically conducted 

 that I have ever met with; but, like many other valuable 

 documents published by authority of the United States Senate, 

 it is not for sale, but, having been distributed promiscuously 

 when published to members of the Legislatiu-e, whether 

 interested in the subject or not, it can now only be obtaine' 

 here and there, at second-hand book-stalls, or at librar 

 auctions in the States. 



The geologists of oiu* parties. Dr. Le Conte and Dr. Parry. 

 fully endorse the conclusions given to the public by Dr 

 Newberry in his Heport, while many of the predictions of that jl 

 distinguished geologist have since been verified. 



The entire Colorado Basin consists of a series of table- 

 lands, piled up one above the other, and covering the whole 

 country. In elevation they vary from 4,000 to 7,000 feet, 

 and reach, in some places, a height of 8,000 feet above the 

 sea. They succeed each other in a series of steps, whii^l* 

 generally present abrupt and wall-like edges, the more recent 







stratum occupying the highest portion of the plateau. 



Complete barrenness is the rule, fertility the rare except 

 scarcely any vegetation, save the Artemisian scrub, is t 

 foimd between the 36th and 42nd parallels ; the earth 

 the most nart, is bare and naked, showinjr the wear and 



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of the nrimeval ocean, and the cracks an 



fissures of the more 



Whence, we may ask, did the material come from, of whic" 



com 



To what cause is due the Mesa, or Table-land featui'e ot 

 this country ? 



