SPRINGS OF THE LAOONTAN BASIN. 



53 



a deep basin and becomes ponded before spreading out over the desert and 

 evapoi-ating. Many of the basins in this group are lined with amorphous 

 calcareous tufa ; and one, filled vvith boiling water, is depositing both silica 

 and tufa. The siliceous sinter precipitated from these waters is gelatinous 

 at first, but soon hardens and forms mushroom-shaped scollops whicli fringe 

 the sides of the basin and the margins of the channel of discharge. The 

 deposition of silica takes place quite rapidly as the water cools, and in some 

 instances imprisons insects that have been killed by venturing into the boil- 

 ing waters. 



An analysis by Dr. T. M. Chatard of one of the most typical of the 

 springs in the group described briefly above, from which calcareous tufa is 

 being deposited, is given below: 



Probable com- 

 biD.atiou (in 

 grammes per 



"iter). 



Silica (SiOa) 



Calcinm (Ca) 



Maunpsiara (Mg) .. 



Socliuiii (Na) 



Potassium (K) 



Lifliium (Li) 



Chlorine (CI) 



Sulphuiic acid (SO4) 



Oxygen* (O) 



Carbonic acid (CO3) 



Total 



0. 1136 

 0. 0367 

 0. 0034 

 0. S.i.M 

 0. 0191 



Trace. 

 0. 2396 

 0. 3901 

 0. 0255 



Trace. 



1. 1834 



9.60 



3.10 



0,29 



:iO. 03 



1.61 



Trace. 



20.95 



32.97 



2.15 



Trace. 



100. 00 



Silica (SiO;.) 



Sodium silicate (N02Si03) 



Calcinm aiilpbate (CaSOa) 



Ma^esinm sulphate (M<;S(>4) 



Sodium sulphate (Na^SOj) 



Potassiixm chloride (KCl) 



Sodium chloride (NaCl) 



Total (99.43 perct. accounted ibr) 



1. 1834 



* Oxygen necessarily added to form Na?Si03. 



Hot springs of considerable volume occur in groups near the southern 

 end of Black Rock Point and along both the eastern and western borders 

 of the Black Rock Range, and also on the borders of the desert at the east- 

 ern base of the Pine Forest Range. Continuing northward, the belt of hot 

 springs we have been tracing is represented in Pueblo Valley by two steam- 

 ing caldrons, and at the eastern base of Stein Mountain other outlets of a 

 similar nature have been examined. Nearly every spring throughout the 

 entire region between Honey Lake Valley, California, and Alvord Valley, 

 Oregon, a distance of over 200 miles, has been observed to occur on a line 

 of recent displacement. 



