Z ERYTHEA. 



I have prepared the following synopsis of the winter temperature 

 of the valley from data f urn is lied by the Honey Lake Land and Water 

 Co., and taken by Mr. L. H. Taylor, C. E. These readings were 

 taken thrice daily, viz.: at 7 A. M., 12 M. and 7 P. M., only during 

 the 63 days from December 25, 1890, to February 25, 1891 : — 



Mean temperature of the period (F.) 33° 



Mean temperature of the warmest day, Feb. 22 48.3° 



Mean temperature of the coldest day, Jan. 10 19.3° 



Maximum temperature, Dee. 25 60° 



Minimum temperature, Jan. 12 7° 



Range 53° 



Greatest daily variation, Dec. 25 and Jan. 9 33° 



Least daily variation, Jan. 7 3° 



Mean daily range of temperature 19.6° 



Mean lowest temperature of the period 24.4° 



Mean highest temperature of the period 44.1° 



The valley floor consists of a deep deposit of alluvial soil of a 

 light yellowish color, largely charged with salts, of which sodium 

 carbonate apparently forms a very considerable proportion. As in 

 other parts of California, the "alkali" salts are not uniformly dis- 

 tributed through the soil, but occur in patches, often of large extent, 

 and sometimes, but by no means always, efflorescing at the surface. 

 A "hard pan" of concentrated salts occurs, usually between 2 and 3 

 feet below the surface, especially where Greasewood, Snrcobatus ver- 

 miculatus, grows. 



The mountains to the south and southwest are granitic; those to 

 the north and northeast form part of the great lava deposit which 

 covers almost the whole of northeastern California. Several springs, 

 at least eight in number, throw up hot, sulphurous water, in geyser 

 fashion, several inches above ground, accompanied by much steam. 

 Springs and streams of water are otherwise scarce on the north and 

 east sides of the valley. 



At the extreme west end of the lake a delta of rich, blackish, 

 alluvial soil has been deposited by the joint waters of Susan River 

 and Willow Creek. Its sloughs and the shallower parts of the lake 

 abound with "tules" (Scirpus lacustris occidentalis), from which the 

 delta has acquired the name of "The Tules" or "The Tule Confed- 

 eracy." It is well watered from the many sloughs by which the river 

 empties itself into the lake, and produces a flora entirely different 

 from that of the arid north and northeast portions of the valley. 



