.Vol. XX, No. 8 



WASHINGTON 



August, 1909 



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THE COLORADO DESERT* 



By W. C. Mendenhall, of the U. S. Geological Survey 



With Photographs by the Author 



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HE Colorado Desert is not in 

 Colorado nor even near that im- 

 perial State. Instead, it is in the 

 extreme southeastern part of California 

 and adjoining parts of Mexico, and 

 represents one of the geographical and 

 physical extremes for which California 

 is noted. 



This state extends for 1,000 miles 

 north and south along our Pacific shore 

 line, so that it passes from tropical to 

 temperate conditions and from the most 

 arid to one of the most humid sections 

 of the continent. It includes the great 

 Sierra, dominated by Mount Whitney, 

 14,501 feet above the sea, while just east 

 of this culminating peak of the United 

 States lies Death Valley, the lowest point 

 on the continent, 276 feet below sea-level. 

 These physical contrasts are matched by 

 contrasts in vegetation and temperature, 

 so that nearly every type of natural 

 environment under which man exists is 

 represented within the boundaries of the 

 state, and often, as in the case of Death 

 Valley and Mount Whitney, the juxtapo- 

 sition is so immediate as to greatly ac- 

 centuate the contrasts. 



The valley of southern California, 

 with its orange and lemon groves, its 



acacias and palms, its geranium hedges, 

 and its riot of roses, is only 100 miles 

 from the region that is the subject of this 

 sketch, originally one of the most deso- 

 late spots on the globe, a veritable fur- 

 nace in midsummer, with recorded offi- 

 cial temperatures of 130 degrees in a 

 shadeless land, but now destined through 

 the ' agency of man to become a unique 

 agricultural section, in which products 

 not capable of production elsewhere in 

 the United States can be successfully 

 grown. 



This desert derives its name from the 

 Colorado River, its creator and until re- 

 cently the erratic master of its destinies. 

 Now the river is sullenly yielding to man 

 the dominion that it has maintained since 

 the evolution of the desert from sea bot- 

 tom to arid valley. This evolution is a 

 very recent event, in a geologic sense, 

 and is one which the scientist is able to 

 decipher with exceptional and satisfac- 

 tory definiteness. 



The desert valley is a northeastward 

 extension of the depression whose south- 

 ern portion is filled by the Gulf of Cali- 

 fornia. During a time that is not at all 

 remote, geologically speaking, the gulf 

 occupied all of this depression, extending 



* Published by permission of the Director, U. S. Geological Survey. 



