64 GBULOGICAL HISTOliY OF LAKE LAHONTAN. 



the levi'l of Pyramid Lakr was 3.800 feet above the sea, and of WiiiiieniVTcca about 80 feet lower. 

 Later, owiug to tbe distnrbaiito of the balance between iuflux and evaporation already alluded to as 

 esprossin^ iiselfiu Utah by Ibe rise and expansion of Great Salt Lake, tbe basin of Pyramid Lake was 

 filled up, and a back water overflowed tbe former region of bifurcation, so that now the surplus waters 

 all go down the channel into Wiuuemucca Lake, and that basin is rapidly tilling. 



Between 18()7, the time of my first visit, and 1871, the time of my last visit, the area of Winiiemucca 

 Lake had nearly doubled, and it has risen from its old altitude about 22 feet, Pyramid Lake in the 

 same time having been raised about i) feet. The outlines as given upon our topographical uuips are 

 according to th^' survey of lH(i7, and form interesting data for future comparison. 



The differences in elevation between Pyramid and Winnemucca lakes, 

 as reported by Mr. King, and as determined by the present survey in 

 August, 1882, are as follows: In 1867 Pyramid was 80 feet higher than 

 Winnemucca (U. S. Geol. Expl. 40th Parallel, Vol. I, p. 505); in 1872 Pyra- 

 mid was 67 feet higher than Winnemucca (U S. Geol. Expl. 40th Parallel, 

 Vol I, p. 506); in 1882 P3'ramid was 12 feet higher than Winnemucca, as 

 determined by engineer's level. 



We know of no accurate means of determining how much each lake 

 individually has varied since 1872, but the decrease in the difference of the 

 levels of the two lakes is certainly due in part to the lowering of the waters 

 of Pyramid Lake, as is indicated by recent tufa deposits and lines of bleached 

 sea-weed at an elevation of about 12 feet above. the present surface of the 

 lake. From the data now in hand, providing that all the measurements 

 are correct, it is evident that Winnemucca Lake has risen over 40 feet since 

 1872, and over 50 feet since 1867. 



The history of the fluctuations of these lakes is supplemented and en- 

 larged by the statements of Mr. George Frazier, who has been familiar 

 with the region since 1862 In his judgment Winnemucca Lake has risen 

 about 40 feet in the last twenty years. In 1862, 1>he branch of the Truckee 

 River that supplies Winnemucca Lake was so low that a person could cross 

 it 1)\- stepping from stone to stone, at a point where it is now not less than 

 25 feet deep. The lake was then confined to the northern extremity of its 

 basin, and the stream reached it after meandering through meadow lands 

 that are now 15 or 20 feet luider water. At that time the channel of the 

 stream could be traced along the bottom of the lake for some distance, and 

 dead cottonwood trees were standing in the water, showing that the lake 

 had previously been nuieh lower. Dead trees standing in Pj-ramid Lake, 

 some distance from the shore, bore similar evidence to the rise of that lake 



