LANDS BEARING POTASH AND RELATED SALINES. 135 



the chances are perhaps greater that potassium-rich saline deposits in 

 this country will vary widely from the German type in the character 

 of the salts and in their mutual associations. It appears, therefore, 

 that a discussion of the geologic occurrence of potash based on the 

 Stassfurt type alone would be inadequate if intended to apply to 

 possible deposits in the United States. 



Potash in its soluble or most useful forms is almost universally 

 associated with other soluble salts. Therefore it is to the natural 

 saline residues and natural or artificial brines and bitterns that atten • 

 tion is directed in an exploration for soluble potash. 



Great deposits of salines, especially those composed of sodium 

 chloride or common salt, occur in many parts of the United States, 

 but so far as known none of the important deposits now worked for 

 salt contain an important percentage of potash salts. Saline beds 

 occur at the surface in the arid regions of the West more abundantly 

 than elsewhere. These occurrences include at least two types of de- 

 posits — the bedded salines included in stratified formations, which 

 have commonly been tilted and otherwise displaced since their depo- 

 sition, and the more recent saline deposits, which are to be found in 

 the undrained playas and salt marshes of the Great Basin region. 



The manner of formation of these more recent saline deposits is 

 clearly revealed by the geologic record of the events that led to their 

 accumulation and deposition. These events are so recent that the 

 changes which are constantly taking place on the earth's surface have 

 not yet obliterated or seriously obscured the evidence. This clearness 

 and completeness of the geologic record justifies confidence in the 

 correctness of the hypotheses concerning the manner of origin of 

 saline deposits of this form. 



Saline deposits in the Great Basin region, as elsewhere, are formed 

 by the accumulation of the water-soluble constituents of the surface 

 rocks of the earth's crust set free by that form of dissolution gen- 

 erally referred to as weathering. These salts thus freed are taken 

 into solution by the rainfall and the ground waters and are gradu- 

 ally removed by the streams from the soils where they originate. 

 Where these streams flow into inclosed basins with no outlet to the 

 ocean, as is the rule in the Great Basin region, the dissolved salts are 

 carried to the lowest part of the drainage area, where they ac- 

 cumulate. In the past, presumably because of greater pre- 

 cipitation than at present, these waters formed large lakes, which 

 have since wholly or in part disappeared, and in the evaporation of 

 these lake waters the salts have been deposited. Examples of saline 

 deposits that have originated in this way in the low parts or so-called 

 sinks of the inclosed drainage areas are common. 

 ■ Saline deposits derived from the wash of continental areas nor- 

 mally contain among other constituents a certain proportion of 



