560 E. HUXTiyOTOX SOLAE HYPOTHESIS OF CLIMATIC CHANGES 



which spilled in turn into the deep structural basin now occupied by the 

 Searles '"lake" or salt marsh. The Searles Basin filled to a depth of 600 feet 

 above its present lx>ttom and overflowed into the Panamint Valley to the east- 

 It is believed by Gale * that the Pauamiut also was filled to the ix)int of over- 

 flow and discharged, for a time at least, into Death Valley over a pass about 

 1.0(X> feet above the floor of the tributaiy valley. There existed, therefore, a 

 chain of four lakes — Owens, China. Searles. and Panamint — each of which 

 overflowed, the final overflow being into Death Valley, in which no evidenc-es 

 of lake c-onditions have been found. In the basins of all four of these lakes 

 terrace systems record the earlier conditions. In Owens the highest and best 

 developed terrace is alwut 250 feet alx)ve the present lake level and marks the 

 level of discharge. Below this are fairly well marked strands at approximately 

 20, 30. and 50 feet alx)ve the present lake, and probably one higher terrace, now 

 much eroded, at perhaps alx)ut 150 feet. The basin of China Lake contains 

 similar strands below the level of overflow, but the writer does not know them 

 in detail. In the basin of the Searles .salt marsh the overflow terrace is very 

 weU developed at appi-oximately 600 feet above the present bottom. Below this 

 is a series of many strands, of which the writer has counted 21. at approxi- 

 mately the following elevations in feet above the present l>ortom of the basin : 

 550. 580, 5CM). 490. 475. 430. 385. 350. 310. 265. 240. 220. 195. 105. 90. 75, 65. 45. 

 40. 35. and 20. The 50<>foot strand is pai-ticularly well developed, being almost 

 as deeply cut as is the overflow (600-foot » terrace. In the lower 200 feet of 

 this terrace series very faint strands IS inches to 2 feet apart can .sometimes 

 be traced between the terraces noted. It seems probable that these fainter 

 markings represent annual stages in the retreat of the ancient lake. A terrace 

 system exists in the Panamint Basin, but is not knoAvn to the writer in detail. 



"In addition to the probable overflow from the Oweus-Searles lake chain. 

 Death Valley fomierly received water from the drainage systems of the Amar- 

 gosa and Mohave rivei"s. the foinner of which still flows in part to the sink. 

 Several small basins now undrainetl were once tributary to one or the other 

 of these rivers and contributed their quota to the former flow.^ This means 

 that Death Valley must have received a c-onsiderable drainage quite regardle.ss 

 of the volume of the overflow from the Panamint. Nevertheless, very careful 

 search has failed to disclose any vestige of former lake conditions in Death 

 Valley, this surprising circumstance remaining quite unexplained. 



"There remain eighteen individual uudraiued basins unconnected with any 

 of the three larger groups and which contain unmistakable evidences of the 

 former presence of lakes. In each ca.^se these lakes were individual and hydro- 

 gi-aphically unrelated to one another. In only one case (the Salton) is there 

 probability of drainage by overflow, and in most eases it is c-ertain that over- 

 flow did not oc-cur. These individual ancient lakes, with some description of 

 their terrace systems, are given in the following pages: 



"Abert Lale. Orcffon. — The highest terrace was measured by the writer as 

 approximately 200 feet above the present Abert Lake.^ Below this are at least 



* Personal communication. 



^ In the list of Bulletin 54 these basins are : Ralston Vallev. Stonewall Flat. Sarco- 

 batus Flat. Pahrump Valley, and Mesquite Valley. Nevada : Soda Lake. Rodriguez Lake. 

 Harper Lake. Coyote Lake. Cronese Lake, and Langford Lake. California. 



•'Russell (U. S. Geological Survey. Fourth Annual Report. 1S84, p. 459) reports a 

 terrace 250 to 3«X) feet higher, but the writer was imable to identify it. 



