RfisuMfi. 253 



it was finally terminated — probably less than 300 years since — by an in- 

 crease in humidity. The present lakes then commenced their existence. 



Throughout its history, Lake Lahontan has been subject to a multi- 

 tude of minor oscillations, as is indicated by the banded and stratified char- 

 acter of the tufa deposits lining the interior of its basin. 



The character of the climatic changes which brought about both the 

 great expansions and contractions of Lake Lahontan; as well as the minor 

 fluctuations to which it was subject, will be indicated, so far as the writer 

 has been able to interpret the records, in the following chapter. 



