238 



D. T. MaeDougal — The Salton Sea. 



The species of higher plants in the Sink number something 

 less than a hundred and fifty, yet in places the mesquite (Pro- 

 sqpis gradulosa) and the screw-bean (P. pubescens) and a half- 

 dozen small trees and shrubs made open forests over consider- 

 able areas which had been covered, and the emergence of these 

 was expected to furnish evidence of value in the interpretation 

 of the earlier stages of fossilization of woody tissues. 



The greater part of the inflow from the Colorado river 

 having been cut off, the phase of the history of the Salton sea 

 or lake with which this discussion is concerned began, and the 

 greater part of the facts of interest are results of the recession 

 of the water level. The factors which would tend to lower the 



Fig. 2. 



Fig. 2. Salt deposit at bottom of sink, February, 1903. 



level of the lake include the evaporation, which would amount 

 to about 116 inches yearly, and the seepage of which no esti- 

 mate could be made. Some supply of water would be contrib- 

 uted by the uncapped artesian wells in the northwestern part of 

 the Sink, by numerous saline and brackish springs, by the 

 underflow from the mountains which bound the Basin, by the 

 run-off from the infrequent rains, and by the wastage and 

 seepage which continued to find its way down the inflow chan- 

 nels of the Alamo and New rivers, and from the tailings of 

 power plants and irrigation systems. The variation in the 

 level of the water from the beginning of the inflow until July, 

 1912, is shown by the tracing in fig. 3, which is reproduced by 

 permission of Mr. H. T. Cory. It was found that the recession 

 from 1907 to 1912 amounted to 40 to 59 inches 'annually, the 

 maximum occurring in 1910. 



