J. LeConte—Ancient Glaciers of the Sierra Nevada. 181 
and probably formed icebergs there. In its subsequent retreat 
it seems to have dropped more débris in its path and formed 
a more perfect terminal moraine than did Fallen Leaf Lake 
Glacier. 
Emerald Bay Glacier—Al\ that I have said of Fallen Leaf 
Lake and Caseade Lake apply, almost word for word, to 
Emerald Bay. This beautiful bay, almost a lake, has also 
been formed by a glacier. It also is bounded on either side 
y moraines, which run down to and even project into Lake 
Tahoe, and may be traced up to the rocky points which form 
the mouth of the cafion at the head of the bay. Its eastern 
true moraine matter, i. e., intermingled boulders and sand, 
which may be examined through the exquisitely transparent 
water almost as perfectly as if no water were present. Some 
of the boulders are of large size. 
All that I have described separately and in detail, and much 
ttle lakes : on either side of these, embracing and protecti 
them, stretch out the moraine arms, reaching toward and 
directing the eye to the great lake, which lies, map-like, with 
all Its sinuous outlines perfectly distinct, even to its extreme 
northern end, twenty-five to thirty. miles away. As the eye 
