356 Adventures in Scenery 



Lake into the granitic mountains. The alluvial slopes east of 

 Soda Lake are very sandy, and because of its desolate character 

 (wind-blown sand) the region is called the Devil's Playground. 

 Silver Lake, 151 miles (El. 909 feet); Silurian (Riggs) 

 Lake, 172 miles; Ibex Pass, 193 miles (El. 2,250 feet); Death 

 Valley Jc., 225 miles (El. 2,000 feet). 



Fault Valley of Soda and Silver Lake 



Playas Once Occupied by Lake Mojave 



The character of the mountains and other features suggest 

 that the great trough occupied by Soda Lake and Silver Lake, 

 as well as the valley farther north, had its origin in faulting 

 that is, a segment of the earth's crust that has dropped between 

 blocks on each side. The great trough extends northward a 

 distance of about 50 miles; thence it bends sharply westward 

 about 10 miles and continues northwestward as Death Valley 

 for many miles. Between Soda Lake and Silver Lake a low 

 divide not more than 10 feet high has been cut through by a 

 stream, and in times of flood water flows from Soda Lake to 

 Silver Lake. 



There is unmistakable evidence that at some time in the 

 past a large lake covered both Soda and Silver Lakes, submerg- 

 ing the low divide between them and reaching beyond the 

 borders of the present playas. The ancient lake was for a 

 long time the end of the Mojave River drainage system, and 

 it is therefore referred to as Lake Mojave. Evidences of the 

 existence of the lake are wave-cut cliffs and terraces, beach 

 ridges, and an unmistakable outlet channel toward the north. 

 The clearest evidence consists of wave-cut cliffs and terraces on 

 the west side of Silver Lake, opposite the town of that name, 

 and also at the northeast end of the playa. Beach ridges are 

 also well developed at the north end of Silver Lake. A promi- 

 nent beach ridge which rises nearly 40 feet above the playa 

 extends westward from the railroad to a limestone hill. For a 

 time Lake Mojave had an outlet northward in the great valley 



