The right lateral of the tributary, which took its rise between Red and Merced Mountains, measures two hundred and fifty feet in height at its upper extremity, and displays three well-defined terraces, similar to those of the south Lyell Glacier.

The comparative smoothness of the upper-most terrace shows that it is considerably more ancient than the others, many of the boulders of which it is composed having crumbled.

A few miles to the westward, this moraine has an average slope of twenty-seven degrees, and an elevation above the bottom of the channel of six hundred and sixty feet.

Near the middle of the main basin, just where the regularly formed medial and lateral moraines flatten out and disappear, there is a remarkably smooth field of gravel, planted with arctostaphylos, that looks at the distance of a mile like a delightful meadow.

Stream sections show the gravel deposit to be composed of the same material as the moraines, but finer, and more water-worn from the action of converging torrents issuing from the tributary glaciers after the trunk was melted.