Its numerous fountains were ranged side by side in three series, at an elevation of from 10,000 to 12,000 feet above the sea.

The first, on the right side of the basin, extended from the Matterhorn to Cathedral Peak; that on the left through the Merced group, and these two parallel series were united by a third that extended around the head of the basin in a direction at right angles to the others.
The three ranges of high peaks and ridges that supplied the snow for these fountains, together with the Clouds' Rest Ridge, nearly inclose a rectangular basin, that was filled with a massive sea of ice, leaving an outlet toward the west through which flowed the main trunk glacier, three-fourths of a mile to a mile and a half wide, fifteen miles long, and from 1000 to 1500 feet deep, and entered Yosemite between the Half Dome and Mount Starr King.
Could we have visited Yosemite Valley at this period of its history, we should have found its ice cascades vastly more glorious than their tiny water representatives of the present day.

One of the grandest of these was formed by that portion of the Nevada Glacier that poured over the shoulder of the Half Dome.
This glacier, as a whole, resembled an oak, with a gnarled swelling base and wide-spreading branches.

Picturesque rocks of every conceivable form adorned its banks, among which glided the numerous tributaries, mottled with black and red and gray boulders, from the fountain peaks, while ever and anon, as the deliberate centuries passed away, dome after dome raised its burnished crown above the ice-flood to enrich the slowly opening landscapes.
The principal moraines occur in short irregular sections along the sides of the canyons, their fragmentary condition being due to interruptions caused by portions of the sides of the canyon walls being too steep for moraine matter to lie on, and to down-sweeping torrents and avalanches.
The left lateral of the trunk may be traced about five miles from the mouth of the first main tributary to the Illilouette Canyon.

The corresponding section of the right lateral, extending from Cathedral tributary to the Half Dome, is more complete because of the more favorable character of the north side of the canyon.