GEOGRAPHIC FEATURES 227 



Inyo range. Occupying the depressions between these groups of moun- 

 tains are extensive valleys, that between the north end of the Silver Peak 

 range and Lone mountain being known as Big Smoky valley, that between 

 the Silver Peak range and Montezuma mountains as Clayton valley, and 

 that on the west, between the Silver Peak range and the Inyo range, as 

 Fish Lake valley. The lowest portions of each of these valleys form 

 playas, covered with an incrustation of various salts, white in color, ren- 

 dering them a conspicuous feature in the landscape. 



The ranges are nearly all quite complex in character. None of them 

 can be said to represent the typical Basin Eange structure. However, the 

 steep slopes of several of them are clearly the result of uplifts along 

 normal faults. To this extent the Basin Eange structure may be said 

 to be represented. The details of these structure features will be given 

 under a separate heading. 



DRAINAGE 



The drainage system consists of waterways, or "washes," which radiate 

 from the ridges toward the valleys. These waterways are ravines and 

 canyons of the ordinary Basin type. On the slopes between the edge of 

 the mountain ridges and the lowest points of the valleys the "washes" 

 are cut chiefly through the older alluvial fans and through Tertiary lake 

 beds. In such cases the banks are commonly precipitous, with a maxi- 

 mum height of about 250 feet. There is usually a flat bottom to such 

 washes, up which one may drive with a light vehicle for long distances. 

 As previously stated, none of these "washes" contains any permanent 

 stream, with the exception of a single ravine hereafter noted. Even after 

 rains the running water in the "washes" seldom reaches the playas of the 

 valleys, and the thin sheets of water covering these playas after rains 

 represent chiefly the material which has fallen on the playas themselves 

 or on their margin. An exception to this is Fish Lake valley, where 

 floods from the Inyo range frequently spread out over the valley. Nearly 

 all the precipitation within the quadrangle either sinks immediately into 

 the ground or is carried down on to the detrital slopes and there dis- 

 appears, while that in the playas is gradually evaporated. 



WATER SUPPLY 



Within the limits of the quadrangle, except after rains, there is no 

 running water whatever except the stream, less than a mile in length, 

 which issues from the Jeff Davis spring, on the east slope of Silver Peak 

 range. If it were not for the occasional springs scattered over the quad- 

 rangle and the possibility of getting water by sinking wells, the region 



