62 



BULLETIN 61, V. S. DEPARTMENT OF AGEICULTUEE. 



nitude. Each of these lakes on evaporation must have left deposits of salines. It ia 

 not improbable that in some cases several separate deposits were left. The Black 

 Rock Desert is at present a comparatively level plain. As far as known, no notable 

 quantities of salines have been discovered. That they exist in some places beneath 

 tne desert sand or absorbed within the muds is probable. The great area of this 

 desert (1,600 square miles approximately within the 4,000-foot contour) and its 

 extreme flatness would render the search for these deposits difficult. Pyramid 

 Lake, the deepest of the present lakes, is 360 feet deep. This basin must have been 



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Fig. 7. — Profiles of Pyramid, Winnemucca, Mono, and Walker Lakes. 



the deepest of the Quaternary basins. It is an open question whether the waters of 

 Black Rock Desert or those of Carson Lake drained into this basin. Present topo- 

 graphic conditions jvould indicate no particular drainage from either place. In fact, 

 if we consider that Pyramid Lake receives the largest stream we would conclude 

 that the overflow from this lake during the intermediate stages of evaporation would 

 have been into the Black Rock Desert and into the Carson. Topographic conditions 

 seem to indicate that Walker Lake did not drain in the direction of Carson Lake. 

 The lowest pass Vjetween Carson and Pyramid Lakes is at Ragtown, and at an elevation 

 of 4,100 feet. If we assume that the Carson and Truckee Rivers had flows relatively 

 the same as at present, we should expect Pyramid Lake to discharge some of its con- 

 tents into the Carson. There are no present evidences as to the direction of flow from 



