PYRAMID LAKE, NEVADA. 5°7 



the streams flowed in the wrong direction and emptied into lakes with- 

 out outlets or into the desert sands. 



As the party (raveled southward into Nevada, they came upon one of 

 the largest and most interesting of the lakes of the Great Basin. Fre- 

 mont says in his journal: "Beyond, a defile between I he mountains 

 descended rapidly about 2,000 feet; and filling all the lower space was a 

 sheet of green water some twenty miles broad. It broke upon our eyes 

 like the ocean. The waves were curling in the breeze and their green 

 color showed it to be a body of deep water. For a long time we sat en- 

 joying the view. It was like a gem in the mountains which from our 

 position seemed to enclose it almost entirely." 'Thus runs (he narrative 

 of the first white man who ever saw this great body of water. Of its 

 source and general relations he knew nothing, but he hoped that it had 

 an outlet and that the stream would lead him westward to California. 



Traveling southward along the eastern shore of the lake, the party 

 came in sight of a great rock rising from it, and camped upon the shore 

 opposite. Fremont says: "It rose according to our estimate 600 feet 

 above the water, and from the point we viewed it, presented a pretty 

 exact outline of the great pyramid of Cheops. This striking feature 

 suggested a name for the lake ami I called it Pyramid Lake." 



The lake thus discovered and named has had an interesting geologi- 

 cal history, and is surrounded by many remarkable scenic features. It 

 occupies the deepest portion of the basin of a much greater lake which 

 once covered much of northwestern Nevada. This extinct lake has 

 been named Lahonton, after an early French explorer. 



It must be understood that the Great Basin, as its name signifies, is 

 an extensive region with no outlet to the ocean. It is made up of in- 

 numerable faulted crust blocks, the elevated ones giving rise to the north 

 and south ranges of mountains and the depressed ones to the desert 

 basins lying between. Each local basin or valley has its own watershed 

 limited by the mountains which surround it, but if for any cause the 

 water supply from these mountains is in excess of the evaporation in the 

 valley, a lake results, and if the supply is sufficient the lake will overflow 

 its own basin and spread into the adjoining basins, rising to a height at 

 which the water lost by evaporation exactly balances the inflow. 



In this manner it was that the great Lake Lahonton spread over the 

 valleys of northwestern Nevada during the glacial period. The Walker, 

 Carson and Truckee rivers, with many smaller ones, all heading in the 

 glacier-covered Sierras, were supplied with a great amount of water dm> 

 ing the heavier precipitation of that period. In addition, the heat was 

 not so great and consequently evaporation was less. 



The ancient boundaries of this lake have been traced and carefully 

 studied, and we know- that during its high-water stage it was second, 

 in size, only to Lake Bonneville, another great lake of the same period 



