394 
TURNER. 
in place exposed near them, while the glacial moraines near 
Johnsville are largely of diabase debris. 
Mr. I. C. Russell, in his paper on the Quaternary basin 
of Lake Mono (XVI), states that the inside as well as the 
ends of some of the lateral moraines at Lake Mono are ter¬ 
raced, showing that the highest stage of the lake either fol¬ 
lowed or continued after the retreat of the glaciers, for the 
inside of the lateral moraines must have been filled with ice 
at the period of maximum glaciation. Mr. Russell suggests 
that the melting of the glaciers produced the maximum 
stage of the lake. 
Professor Le Conte (X) considers that the absence of 
terminal moraines can be accounted for on the hypothesis 
that the maximum stage of the glacier and that of the ice 
coincided, for then the loose material that would have 
formed a terminal moraine would be carried away by float¬ 
ing ice. Professor Le Conte accounts for the presence of 
large boulders at certain points about Lake Mono by sup¬ 
posing them to have been transported by icebergs. 
When at Lake Mono, in 1889, in company with Mr. G. F. 
Becker, it was observed that a rough stratification existed in 
the end of the Lundy moraine, the material being well ex¬ 
posed by mining operations; and in the opinion of Mr. 
Becker this would show that the end of the glacier extended 
into the water, the morainal material being roughly strati¬ 
fied as it dropped off. 
The true explanation may be that the high stage of the 
water was both contemporaneous with and continued after 
the retreat of the glaciers. On this hypothesis the internal 
stratification of the moraines, the terraces on their inner 
sides, and the stranded boulders would be explained. 
It was not till after this paper was read before the Society 
that I found that Mr. Gilbert had treated the subject of the 
correlation of glaciers and the Pleistocene lakes of the great 
basin very fully. On page 314 of his monograph (VI) Mr. 
Gilbert says: 
“ With one voice these four localities tell us that Mono 
Lake occupied its maximum level after the glaciers of the 
