60 



BULLETIN 61, V. S. DEPARTMENT OF AGRICULTUEE. 



The accumulation of sodium sulphate in the center is of interest. The absence of 

 potassium compounds in the brine and the low content in the marginal deposits are 

 conspicuous. The accumulations in Sevier Lake are undoubtedly due to compara- 

 tive recent action. Deeper bores would have revealed more of the history of the 

 basin and perhaps beds of salines characteristic of the Bonneville period would have 

 been discovered. 



BLACK ROCK DESERT. NEVADA. 



The Black Rock and Smoke Creek Deserts are of notable extent. The northern 

 extension of Lake Lahontan occupied this area, but no surface deposits of salines have 

 been discovered. Some saline crusts can be found, but these are of little importance. 

 A 500-foot well was put down at Sulphur, on the line of the Western Pacific Railroad 

 and on the edge of the mud flat, but neither oil nor salines were found. West of 

 Gerlach, salt is produced in small quantities by the evaporation of brines obtained from 

 shallow wells. 



But few data of a chemical nature are available for this area. In the vicinity of 

 Gerlach samples of mud were obtained from a shallow auger hole. From the same 

 vicinity water samples were also obtained. The analytical results are given below. 

 The muds show a high content of salines, and these consist of chlorides and sulphates, 

 together with small quantities of carbonates. The potassium content is about what 

 would be expected. The mud is a tenacious clay. The waters are somewhat similar 

 in composition to the salines contained in the clays. 



Analyses of saline crust and muds from the Black Rock Desert, Nevada. 



Sample and depth. 



Percentage of total soluble salts. 



Total solu- 



Ca. 



Mg. 



Na. 



K. 



CO3. 



HCO3. 



SO4. 



CI. 



ble salts. 



Surface crust 



P.ct. 

 1.56 



.78 

 .71 

 .63 

 .68 



P.ct. 

 ■0.02 



.02 

 .03 

 .02 

 .03 



P.ct. 



34.41 



35.90 

 36.09 

 36.32 

 36.48 



P.ct. 

 1.12 



2.32 

 2.06 

 2.28 

 2.33 



P.ct. 

 0.06 



.16 



Tr. 











P.ct. 

 0.10 



.33 

 .66 

 .49 

 .35 



P.ct. 

 21.36 



6.85 

 7.84 

 4.97 

 4.07 



P.ct. 

 40.99 



53.63 

 52.57 

 55.37 

 56.03 



P.ct. 

 59.68 



Muds: 1 



0-1.25 feet 



18.31 



1.25-2.5 feet 



23.19 



2.5-3.75 feet 



24.83 



3 . 75-5 feet 



34.47 







I Average ratio Na to K in muds is 16. 

 Analyses of waters from the Black Rock Desert, Nevada. 



Sample. 





Percentage of total solids 



Dn evaporation 





Ca. 



Mg. 



Na. 



K. 



CO,. 



HCO3. 



SO4. 



CI. 



P.ct. 



P.ct. 



P.ct. 



P.ct. 



p.ct. 



P.ct. 



P. ct. 



P.ct. 



0. 48 0. 08 



36.03 



1.49 



0.10 



0.46 



4.64 



55.11 



2.11 .06 



32. OS 



2.73 



.19 



2.97 



8.13 



47.57 



2.48 



Tr. 



32.63 



2.70 







1.35 



11.25 



47.93 



Solids on 

 evapora- 

 tion. 



Water from surface trench 



Average, 4 springs 



Boiling hot spring 



Parts per 



100.000. 



5,209 



428.4 



444 



[Saline clays and crust from point 1.5 miles northeast of Gerlach, Nev. Watei from surface trench from 

 same place. Samples by W. S. Palmer; analj'ses by J. A. Cullen.] 



The waters from the "four springs averaged were taken 0.25 mile from Gerlach. The temperature of 

 these springs ranged from 16.1° to 32.2° C. Samples by \V. S. Palmer: analyses by S. C. Dinsmore. 



The boiling spring was three-fourths mile northwest of Gerlach. Sample by W. S. Palmer: analyses 

 by J. A. CuUen. 



BURIED DEPOSITS OF SALINES. 



The deposits resulting from the desiccation of Searles Lake are exposed on the 

 surface and their discovery was a simple matter. Geological reasoning indicates 

 that the conditions exemplified by Searles must have been repeated at other places 

 in the Great Basin. Evidences of Quaternary lakes are to be found in a number of 

 places, but not in all places do we find the expected saline deposits. The largest 

 Quaternary lake basin, excepting Bonneville, is Lahontan, and it is now occupied 

 by Pyramid, Walker, Humboldt, Carson, and Winnemucca Lakes. Unlike Mono, 



