THE CARSON DESERT. 749 



It contains also traces of phosphoric and boracic acid. The insoluble 

 residue consists of fine sand and carbonate of lime. 



Gay-Lussite is constantly forming in the waters, and is deposited in 

 very perfect crystals, both on the small island which rises scarcely 2 feet 

 above the water-level about 25 feet out from the northwest shore, and on 

 small branches and twigs that are thrown into the lake. The branches, 

 becoming saturated with water, sink to the bottom, and upon being brought 

 to the surface are found encrusted with delicate yellowish-white crystals 

 »f Gay-Lussite. They are translucent, quite brittle, and of a characteristic 

 vitreous lustre. An analysis of a crystal, by Professor Allen, gave the 

 following constituents : 



Lime ----.-. - 19.19 



Soda 19.95 



Carbonic acid 29.55 



Water..-- --...-- 31.05 



Sulphuric acid trace 



Chlorine trace 



Insoluble residue 0.20 



99.94 



which, but for the admixture of small quantities of a sulphate and chloride, 

 approaches closely the required theoretical composition. 



The water appears to be wanting in animal life, with the exception of 

 a minute fly, the larva of which is a small worm, accumulating in such 

 large quantities as to form a belt a foot wide along the shore. It is occa- 

 sionally gathered by the Pah-Ute Indians, and, after drying and pulverizing, 

 made into a sort of meal or flour. In the autuinn, when the water becomes 

 somewhat dense, the larvse are completely coated with carbonate of lime, 

 and transformed into an irregular mass of mineralized matter. 



The smaller of the two lakes, in most of its features, bears a close 

 resemblance to the one just described, and from which it is separated by a 

 narrow ridge only an eighth of a mile wide. It has the same crater-shaped 

 basin, but the banks are not more than 60 or 70 feet in height, and the lake, 

 even in spring, is scarcely more than one-fifth of a mile in diameter. There 



