STUDIES ON SOME LAKES IN THE ROCKY AND 
SIERRA NEVADA MOUNTAINS. 
CHANCEY JTTDAY. 
(With Plates XLVIII-L). 
Many beautiful bodies of water which vary in size from 
mere pools or tarns to bodies of considerable size, are found in 
the higher portions of the R-ocky mountains in Colorado and 
of the Sierra Nevada mountains in California. From some 
high vantage point, a dozen or more of these mountain “gems” 
may often be seen dotting the landscape below. The climatic 
conditions to which these lakes and lakelets are subject make 
them very interesting objects for study from a biological stand¬ 
point. During the summers of 1902, 1903 and 1904, some in¬ 
vestigations were made on a few of these lakes for the United 
States Bureau of Fisheries, It is the purpose to present here 
a brief account of some of the results of the investigation, 
TWIN LAKES,, COLORADO. 
These two beautiful sheets of water are situated in the 
southern part of Lake county^ Colorado, on the west side of 
the valley of the Arkansas river. They lie in the highest part 
of the Rocky mountains of Colorado. A short distance to the 
west of them are three mountain peaks whose altitudes range 
from 4,371 to 4,395 meters, while the lakes themselves are 
2,800 meters above sea level. They lie a short distance below 
the mouth of Lake Creek canyon, and the basins which they 
occupy were doubtless scooped out by the glacier which at one 
time flowed down this canyon. As the glacier receded, two 
