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NATIONAL GEOGRAPHIC MAGAZINE 



Vol. XI SEPTEMBER, 1900 No. 9 



THE COLORADO DESERT 

 By David P. Barrows 



Tlie Colorado River, its canon valley, and flood-plain constitute a 

 series of physiographic conformations of impressive variet}'. The 

 upper part of its course has been eroded across the great elevated 

 plain of western America, through which it has cut its channel down- 

 ward with so great rapidity that its valley walls, almost unaffected in 

 comparison b}^ weathering, rise sheer upward in the gigantic system 

 of gorges known as the Grand Canon of the Colorado. From the point 

 where it enters California it is no longer a downward eroding stream, 

 but sweeps grandly across the sterile plain of the desert, a dark, 

 sediment-laden current, swinging back and forth across its widening 

 valle3^ As it nears the Gulf of California and the rapidity of its 

 stream lessens, the enormous loads of fine rock material, cut from the 

 valleys through which it has torn its way, are deposited in a great (lood- 

 plain or delta, across which the stream pours south into the gulf. 



As above this delta the low banks are unwatered, except at tlie very 

 margins of tlie river, tlie sterility of the sur;-ounding country is un- 

 affected b}' its immense volume of water. 



From whatever direction you approach the river within California 

 or Arizona, the trail lies across sand}' hill and thirsty plain, where are 

 the dark marks of old volcanic activity, grotesque rock forms, sliajied 

 Ijy wind erosion, and occasional stunted clumps of desert plants, with 

 extremely modified foliage; l)ut nowhere is there suggestion that you 

 are upon the l)anks of tlu; mightiest river of western America, until 

 suddenly the ground drops slightly, and in an instant tluux' conic 

 the dark green (coloring of mescpiite growth, the bright foliage of 

 cottonwixjd and willow, tlir; dazzling gleam of wide waters, (lowing 

 swiftly, and yon are Ixjside the long, shining river of liOpez de Cardmas 

 and Alarcon. 



