Toward the middle of the afternoon I came to another valley, strikingly wild and original in all its features, and perhaps never before touched by human foot.

As regards area of level bottom-land, it is one of the very smallest of the Yosemite type, but its walls are sublime, rising to a height of from 2000 to 4000 feet above the river.

At the head of the valley the main canon forks, as is found to be the case in all yosemites.

The formation of this one is due chiefly to the action of two great glaciers, whose fountains lay to the eastward, on the flanks of Mounts Humphrey and Emerson and a cluster of nameless peaks farther south.
[Illustration: HEAD OF ROCKY MOUNTAIN WILD SHEEP.] The gray, boulder-chafed river was singing loudly through the valley, but above its massy roar I heard the booming of a waterfall, which drew me eagerly on; and just as I emerged from the tangled groves and brier-thickets at the head of the valley, the main fork of the river came in sight, falling fresh from its glacier fountains in a snowy cascade, between granite walls 2000 feet high.

The steep incline down which the glad waters thundered seemed to bar all farther progress.