POTASH SALTS AND OTHER SALINES IN THE GREAT BASIN REGION. 59 
extremely difficult to locate these beds. Until proved otherwise by a number of 
bores, Railroad Valley must be looked upon as a possible source of buried salines. 
The question as to whether these salines will be characterized by a high potassium 
content is an open one. The finding of surface crusts and brines of relatively high 
potassium content proves nothing as far as we know at present about the buried salines 
and brines. A possible explanation of the high potassium content in the surface salines 
and brines may be found in the fact that there are a number of hot springs in this 
area, and these may have been responsible for the surface salines. Until analyses of 
the waters of these springs are available this is only conjecture. 
SAND SPRINGS FLAT. 
Sand Springs Flat areais described on the United States Topographic Sheet as ' ' Eight- 
mile Flat" and "Fourmile Flat." It was called "Alkali Valley" in Russell's Mono- 
graph on Lahontan Lake. It lies 11 miles southeast of Fallon, in Churchill County, 
Nev. The area is about 37 square miles. It has a peculiar interest in that a bay of 
Lake Lahontan once occupied the area. The highest level of Lake Lahontan was 439 
feet above the present flat, elevation 3,961. The desiccation of Lake Lahontan would 
have left a shallow lake upon the flat, and this, on evaporation, would have left a bed 
of salines. Russell states that the salt bed is from 3 to 5 inches thick near the margin 
and in the central portion is not less than 3 feet thick. Rain water has collected the 
salines in the southeast end of the flat. Russell x states that after rains a shallow 
brine lake of several inches depth and about 15 square miles in area occupies this 
portion. No notable amounts of potassium have been reported from the salines of 
this area. 
SEVIER LAKE. 
Sevier Lake is in we6t-central Utah, Millard County. It is of some interest in that 
it was formerly a part of Lake Bonneville and for a long time was occupied by a shallow 
lake, which in recent times has dried up. Gilbert 2 describes the history of this lake. 
From his account I take the following: 
Sections of the saline beds in the central and marginal portions of the dried lake. 
Central. 
Marginal. 
1. Top. Sodium sulphate, 2 inches 
2. Sodium sulphate with some sodium chloride, 1 
inch. 
3. Sodium sulphate, 2 inches 
4. Gray clay containing woody fiber, 2 inches 
5. Fine sand containing fresh water shells, 6 
inches. 
6. Gray clay 
1. Top. Sodium chloride crust, \ inch. 
2. Sodium chloride with sodium sulphate and mag- 
nesium sulphate— free crystals mingled with water, 
1J inch. 
3. Sodium sulphate with sodium chloride, a crust of 
coherent crystals, i inch. 
4. Sodium chloride with sodium sulphate; incoherent 
crystals mingled with water, 1J inches. 
5. Sodium chloride, with sodium sulphate, chemically 
identical with No. 2, but fine-grained and with the 
consistence of an ooze; color white above, with oc- 
casional passages of pink and green beneath, \ inch. 
6. Dark-gray mud, 2 feet. 
The analyses upon these from the same reference are given in the succeeding table: 
Constituent. 
Center. 
Margin. 
Brine. 
Sodium sulphate 
Per cent. 
84.6 
.4 
7.0 
Per cent. 
14.3 
Per cent. 
15.5 
Sodium carbonate 
Sodium chloride 
80.62 
72.1 
Calcium sulphate 
Magnesium sulphate 
5.5 
Magnesium chloride 
11.9 
Potassium sulphate 
.7 
3.6 
.1 
Water 
Insoluble 
100.00 
100.00 
100.00 
Monograph No. 11, U. S. Geol. Survey, p. 235. 2 Monograph No. 1, TJ. S. Geol. Survey, p. 244. 
