369 



slowly, more highly charged with salts derived from the rocks 

 over and through which the water passed. 



Owens Valley is a depressed floor between high mountain 

 ranges, formed by the faulting of the rocks on either side and 

 the elevation of the mountains. It is a structural valley and 

 not a valley of erosion. Owens River flows across the flat bot- 

 tom of the valley from far north in the mountains. The valley 

 offers a highway for the passage of the waters from the moun- 

 tains. In Pleistocene time the waters of Owens Lake over- 

 flowed southward over the low divide at Haiwee Reservoir. 



Owens Lake at one time stood at a much higher level than 

 now. This is shown by beach ridges and shore marks around 

 the flat basin. Beach lines on the east slope of the Alabama 

 Hills are 220 feet above the present lake level. Distinct gravel- 

 covered beach remnants may be observed just northeast of 

 Swansea, three miles north of Keeler. Old shore lines show also 

 along the valley margin between Swansea and Keeler. The 

 lake was lowered about 30 feet by erosion of its outlet. The 

 water stood at 190 feet above the present lake level when dis- 

 charge by the outlet ceased. Since this time the surface of the 

 water has been lowered by evaporation alone. The area of the 

 lake at this time was about 240 square miles (the present area 

 of the lake is approximately 97 square miles) . The period of 

 desiccation since the lake ceased to overflow, during which time 

 the concentration of salts to the present brine has been going 

 on, is estimated to have been in the neighborhood of 4,000 

 years. Salt in commercial quantities is taken from the desic- 

 cated ancient bottom of the lake at Keeler. 



Mount Whitney, 1 miles west of the highway at Lone Pine, 

 rises 14,501 feet above sea level (highest point in the United 

 States) . At one time in the recent geologic past waters from 

 the crest of the Sierra Nevada, in the vicinity of Mount Whit- 

 ney, moved through Owens Valley to Searles Lake and Pana- 

 mint Lake and probably to Death Valley, the lowest point in 

 the United States. 



