Nearly all the upper part of the basin of the Tuolumne Glacier is in sight, one of the greatest and most influential of all the Sierra ice-rivers.

Lavishly flooded by many a noble affluent from the ice-laden flanks of Mounts Dana, Lyell, McClure, Gibbs, Conness, it poured its majestic outflowing current full against the end of the Hoffman Range, which divided and deflected it to right and left, just as a river of water is divided against an island in the middle of its channel.

Two distinct glaciers were thus formed, one of which flowed through the great Tuolumne Canyon and Hetch Hetchy Valley, while the other swept upward in a deep current two miles wide across the divide, five hundred feet high between the basins of the Tuolumne and Merced, into the Tenaya Basin, and thence down through the Tenaya Canyon and Yosemite.
The map-like distinctness and freshness of this glacial landscape cannot fail to excite the attention of every beholder, no matter how little of its scientific significance may be recognized.

These bald, westward-leaning rocks, with their rounded backs and shoulders toward the glacier fountains of the summit-mountains, and their split, angular fronts looking in the opposite direction, explain the tremendous grinding force with which the ice-flood passed over them, and also the direction of its flow.

And the mountain peaks around the sides of the upper general Tuolumne Basin, with their sharp unglaciated summits and polished rounded sides, indicate the height to which the glaciers rose; while the numerous moraines, curving and swaying in beautiful lines, mark the boundaries of the main trunk and its tributaries as they existed toward the close of the glacial winter.