Kneeland. ] 36 [February 21, 
ON THE GLACIERS OF THE YOSEMITE VALLEY. By DR. 
SAMUEL KNEELAND. 
There have lately come into my possession some interesting, and 
I think, conclusive observations as to the former great extent of the 
clacier system of the Sierra Nevada Mountains, in the neighborhood 
of the Yosemite Valley. They seem'to throw light upon the.causes - 
which formed the valley, or rather, by way of exclusion, upon the 
forces which did not form it. Before calling your attention to these 
observations, which have recently been made by Mr. John Muir, a gen- 
_ tleman who has made the region of Yosemite his study for years, and 
who records thus his personal examinations, it may be well to say a 
few words on the physical configuration of the region, that the force 
of his remarks may be better appreciated. The maps of the Geo- 
logical Survey of the State will furnish all the explanation required. 
In all this immense region, with a radius of fifteen miles at least, 
there are now no proper glaciers, though there are large accumula- 
tions of snow upon the higher crests and in their valleys, whose melt- 
ing in the summer gives rise to the magnificent cataracts of the Yo- 
semite Valley. The rocks, as every traveller there knows, are 
smoothed and polished to the very edge of the valley, showing the 
former existence of an immense sheet of ice. What ordinary travel- 
lers saw on a limited scale, Mr. Muir has examined on a very large 
scale, having traversed the upper Sierra in all directions, and ascer- 
tained the existence of a glacier system, frequently alluded to in the 
“ Geology of California” published by the State, whose size and 
direction had previously been rather guessed at than determined. 
That there are no glaciers there, as in the Alps, and comparatively 
little snow remaining till summer, is accounted for by the rapid evap- 
oration in the very’ dry air of these high ranges. Not only are 
grooved polishings found, but well marked moraines in the higher 
part of the range; but they do not exist to any great extent in the 
valley proper, though they are traced far down the three great 
cafions at the eastern end, the Tenaya, Merced or Nevada, and IIli- 
louette or South cafions. There is a well marked median moraine 
from the union of the Nevada and Tenaya glaciers, on the north 
side of the Merced river, near the hotels — well rounded, and now 
overgrown with large trees. The markings indicate a former gla- 
cier extending from Mt. Dana and Mt. Lyell, 13,000 feet hich, fifteen 
miles in length and more than a mile thick to the edge of the valley; 
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