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AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Akt. XX Y. — Notes on the Colorado Canyon District; by 

 W. M. Davis. 



A visit to the district of the Colorado Canyon leaves the 

 traveler with a deepened impression of his indebtedness to the 

 three explorers from whom an understanding of that marvelous 

 region has come. Newberry, crossing the plateaus south of 

 the canyon in 1858, recognized the deep erosion of the funda- 

 mental crystallines before the deposition of the Paleozoic 

 series, and the extensive denudation of the plateau uplands 

 where the retreating escarpments succeed each other in order 

 of age; he made explicit statement that not only the canyon 

 but the escarpments of the plateaus " belong to a vast system 

 of erosion, and are wholly due to the action of water."* 

 Powell's adventurous expedition down the river in 1869, justly 

 classed with the most daring explorations of the continent, 

 added an account of the division of the plateaus into huge 

 blocks by faults and monoclines trending about north and 

 south, in contrast to the cliffs of erosion which in a general 

 way trend east and west ; he clearly stated that " the cliffs of 

 erosion are very irregular in direction, but somewhat constant 

 in vertical outline ; and the cliffs of displacement are some- 

 what regular in direction, but very inconstant in vertical out- 

 line."f Dutton's more elaborate surveys of the canyon and of 

 the plateaus to the' north of it in 1879 and 1880, aided by 

 Holmes' wonderful drawings, have made the canyon district 

 classic ground, the type of all that is gigantic in displacements 

 and denudation, the region to be cited, at home and abroad, as 



* Ives Expedition : Eeport upon the Colorado River of the West, Washington, 

 1861. Part III, Geological Report, 45. 

 f Exploration of the Colorado River of the West, Washington, 1875, 191. 



Am. Jour. Sci.— Fourth Series, Vol X, No. 58. — October, 1900. 

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