y theories have been advanced to account for the origin and the extraordinary features of this valley, especial prominence being given to subsidence, uplift, explosion, with earth

ms. There is much evidence to support this conclusion. The ice theory is championed by John Muir, by Clarence King, and by F. E

places it is composed of fissured rock that was more readily carried away by the ice than t

ned in a marked measure by the rock-structure. That is to say, the dense quality of the rock, the number and the position of the cleavage joints, or their abse

t of the valley. It appears certain that this must have been left when the ice vanished; and apparently it formed a lake that filled the entire valley nearly to the height of the dam. The lake finally filled with sedime

in this wonderland. Polished domes predominate. Much of the rock-surface was dense granite comparatively free from cleavage lines, soft materials, or stratification. The forms made by the ice in t

from fifteen hundred to two thousand feet high, its length is about three miles, its width one half-mile. Its floor, like that of th

ape. The forces of erosion are steadily at work; most of t

is the product of a long and complicated series of events. It has been wrought out by many erosive forces. It probably has been acted

glaciers of the region took on vast proportions. An enormous and deep ice-field accumulated from the snows of Mounts Dana, Lyell, Gibbs, McClure, Conness, and other peaks. Flowing westward, it came in contact with Mount Hoff

it but deeply overflowed the highest points on its walls. Passing out of the lower

er lakes, mostly small. Others have filled with sediment and are hidden and forgotten. Lake Tenaya, the Lake-of-the-Shin