V.) (3g '!•' BULLETIN 61, U. S. DEPAKTMENT OF AGKICULTUEE. 



-:>.., !.. - I i Q^otjp II. — Basins in which there are no evidences of Quaternary lalces. 



--• 'wn*!' Square miles. 



' ■ A", Death Vallev, includes Amargosa drainage and basin 23, 160 



B. Silver Peak." 550 



io' ' Rhodes Marsh 540 



vl.o.i Teels 320 



• noil- AH other basins in which the playa contains notable quantities of brine 



'V/! and in which the brines are close to, or at, the surface. 



'i > 'C. All other desert basins and playas not included in the above groups. 



The order given in each main group is the order of relative importance. In each 

 subgroup the order given is the order of areal importance. Groups A and B of each 

 main group are believed to be the most favorable areas for exploration work. Group 

 II is of very much less importance than Group I. 



Of the basins enumerated above, Searles is the only one in which the investigation 

 has shown sufficient concentration of potassium salts in the residual brines to be of 

 probable commercial importance. The salines associated with the potassium salts and 

 the possibility of producing several products predict success in the exploitation of this 

 area. The chemical problem of separating the several salines is a difficult one, and 

 upon its solution hinges the success of the enterprise. The presence of brines of mod- 

 erate concentration is shown in Death Valley and Silver Peak.^ It is a matter of 

 some doubt whether these brines can be worked. The investigation of the Carson 

 Sink, Railroad Valley, and Columbus Marsh is inconclusive. Until the possibilities 

 of the areas considered most favorable have been exhaustively studied, it is inadvisable 

 to attempt exploration of the other areas. 



1 The potassium in the surface brines of the smooth salt area of Death Valley is equivalent to 1.72 per cent 

 potassium chloride; in the brines from the Survey's bores in Death Valley it is equivalent to 0.94 per cent 

 and la the brines of Silver Peak Marsh 1.50 per cent. But comparatively little concentration would be 

 required in these brines to produce a brine of the same content of potassium chloride as the Searles brine. 

 The Death Valley surface brine would have to be concentrated one-half, the deeper brines one-fourth, and 

 the Silver Peak brine somewhat less. than one-half. In Death Valley the summer evaporation rate for a 

 brine is said to be from 24 to 30 inches per month- The cost of evaporatins: a brine under such conditions 

 would be almost nothing. The amount of bTine available for pumping and the practicability of construct- 

 ing vats upon the smooth salt area would have to be determined by detailed examination and experimenta- 

 tion. In my opinion the experiment of producing potassium salts by evaporating the Death Valley brine 

 is well worth carrying out, presupposing that the detailed examination shows a sufficient quantity of 

 brine. 



