50 GEOLOGICAL HISTORY OF LAKE LAHONTAN. 



abundant deposit, consisting principally of common salt and sodium sul- 

 phate, is t'ound At one time these waters were thuught to contain sufficient 

 boracic acid to l^e of economic importance, and an attempt was made to 

 separate it, but the experiment was a failure. There is no evidence to 

 show that this spring was active during the existence of Lake Lahontan. 



A number of small springs, some of which are warm, occur on 

 the west side of Winnemucca Lake. Farther northward small springs of 

 pure cold water have- been found on both sides of the Selenite Range.^" 

 Near the north end of this range, but isolated from it, stands Hot Spring 

 Butte, once a small island in Lake Lahontan. The butte derives its name 

 from a copious sjiring with a temperatui'e of 180° F. which discharges about 

 20 gallons per minute, llie water flows northward for about a mile, and 

 forms a shallow pool in the desert, where it is evaporated. Other hot 

 springs occur northward of Hot Spring Butte, near the southern end of the 

 Jackson Range. 



Numerous copious springs of all temperatures, from the mean of the 

 region up to the boiling point of water, come to the surface along the west- 

 ern border of the Lahontan basin, from Honey Lake Valley to the Oregon 

 boundary. The majority of these have formed circular basins that are 

 tilled with beautifully clear water, and are sometimes of great depth, as in 

 the cas* of Deep Hole, Round Hole, and the group at the east end of 

 Granite Mountain. The bottoms of the basins are usually of flocculent 

 mud, through which the water issues, frequently accompanied by bubbles 

 of gas. In common with very many other hot springs, these basins are lined 

 with deep green confervoid growths. Many of the springs in the belt indi- 

 cated exhale sulphurretted hydrogen, and deposit amorphous, calcareous 

 tufa In one instance silicious sinter is precipitated as the water cools. 

 All the springs in this belt occur either on fault lines that have been 

 disturbed by orographic movement since the withdrawal of the waters of 

 Lake Lahontan, or are very closely related to such lines of displacement. 



'^This range is about 30 miles long aud exteuds from the uortli eud of Wiuuemucea Lake to Hot 

 Springs Butte; it is structurally distiuct from tho Natcliesor TruckeeEaugc, which follows the eastern 

 shore of Winnemucca Lake. I have named it in reference to extensive deposits of crystallized gyp- 

 sum or sclcnito that outcrop along its western border. 



