326 J. LeConte—Ancient Glaciers of the Sierras. 
the base of Cathedral Peak, to the Tuolumne Meadows at Soda 
Springs. Here we left the Mono trail and went up the Tuolumne 
meadows to the foot of Mt. Lyell, and climbed this mountain. 
From Mt. Lyell we returned to the Mono trail, and followed it 
over Mono pass, down Bloody Caiion to Lake Mono and the 
extinct volcanoes in that vicinity. From Lake Mono we went 
northward, among the mountain valleys on the east side of the 
crest, to Lake Tahoe; and then by Johnson’s pass and the Pla- 
cerville road to Placerville and Sacramento and so back to Oak- 
and. From the Yosemite to Mt. Lyell I was accompanied by 
Mr. Muir and Mr. Galen Clark, both men of rare intelligence 
and accomplished mountaineers. 
uring my previous visit the route was a little different. 
From Yosemite to Soda Springs I took the Coulterville Mono 
trail, which passes by Mt. Hoffman and Lake Tenaya. On that 
occasion too I ascended Mt. Dana. The whole distance (near 600 
miles) in both cases was accomplished on horseback. I had, 
therefore, good opportunity and leisure for observing. I found 
abundant evidences of ancient glaciers in almost every part of 
the Sierra. Among those observed I will select a few of the 
most interesting. 
I. Tae Yosemire or Mercep GLacter. 
There can be no doubt, I think, that the Yosemite valley was 
once filled to its brim by a great glacier. Whitney, in his Geo- 
logical Survey, distinctly states his belief that a glacier once 
occupied this valley to the depth of 1000 feet; this belief be- 
ing ss founded upon the supposed remains of old moraimes 
liscovered by Mr. King.* But this opinion he subsequently re- 
‘tracted in his Yosemite Guide Book,+ and now thinks there 1s no 
‘sufficient evidence of the former existence of such a glacier. In 
my opinion his first conclusion is undoubtedly the correct one. 
t is true that glaciated surfaces are not made out with cer- 
tainty in the main valley, and the terminal moraines are not 80 
clear as might be desired; but glaciated forms are unmistak- 
ably observable on the walls of the valley in many places, and 
in some places even to the brim. 
n order to understand why there has been so much doubt as 
to the former existence of glaciers in the lower valleys of the 
Sierras, it must be remembered in the first place that the granite 
in this region decomposes very rapidly; and in the secon 
place that an immense period of time separates the epoch of the 
reat glaciers such as that of which we are now speaking, and 
that of the smaller glaciers which occupied only the upper pol 
tion of the higher valleys. It is in these upper valleys only 
that glaciated surfaces are very conspicuous. And yet eve? 
* Vol. 1, p. 422 and seq. + p. 73. 
