CALIFORNIA ALKALINE AND BORACIC LAKES. 225 



THE ALKALINE AND BORACIC LAKES OF CALIFORNIA. 



Immediately east of the range of the Sierra Nevada is an extensive 

 region of alkaline lakes and hot springs, of which very large areas are almost 

 totally barren, the only vegetation consisting of wild-sage, yucca, a few 

 cacti, and scanty tufts of bunch-grass. 



This district affords, in its many extensive craters and in its lavas, ba- 

 salts, and obsidians, the most conclusive evidence of its volcanic origin, 

 while its solfataras and boiling sjDrings may be regarded as the last repre- 

 sentatives of active vulcanicity. The region is one of great scientific inter- 

 est, and, as it may eventually become industrially important, it has been 

 thought that a brief description of the district, as well as of that of the 

 borax-lakes, lying on the western side of the Sierra, might not be without 

 general interest. 



The most remarkable of the alkaline lakes of this portion of California 

 are Mono and Owen's Lakes. The former lies in a depression occupying a 

 portion of an elevated plateau of desert land, situated at the eastern base 

 of the Sierra Nevada between the head-waters of Owen's and "Walker's 

 Elvers. The distance from the summit of the range to the lake-shore is 

 about six miles, and the difference of elevation is about 6,000 feet. On all 

 sides, excepting toward the Sierra, this lake is surrounded by a wide belt of 

 desert, the total area of which is from 400 to 500 square miles. 



Mono Lake is about fourteen miles long, from east to west, and nine 

 wide, from north to south; but it was formerly much larger than it is at 

 present; this is indicated by numerous terraces, by means of which the 

 line of its ancient shores may be readily traced. 



The water of this lake, which has a high specific gravity, and is alkaline 

 and extensively saline, is not easily thrown into waves, but is generally 

 smooth and glassy. Near its north shore there are springs which have pro- 

 duced extensive deposits of tufa, some of which rise several feet above 

 the surface in forms resembling gigantic fungi. 



There are numerous islands in this lake, two of which are of consider- 

 able size, the largest being two and a half miles long, from north to south, 

 and the other about half a mile in length, from east to west. These, as 

 well as a group of smaller islets lying to the north, are entirely composed 

 of volcanic materials. 



On the northeastern corner of the larger island are extensive hot springs 

 and steam-jets, covering an area of some thirty acres, and extending into the 

 lake. The escape of steam and hot gases from so many hundreds of vents 

 is attended with much noise, and the sides of the orifices of many of the 

 fumaroles are incrusted with a reddish-brown substance, which is probably 

 chloride of iron. In the neighborhood of these springs there is a slight 

 smell of sulphurous acid, but no free sulphur is deposited. Some of them 

 furnish a copious supply of boiling water, large quantities of which enter the 



3 



