I must now make haste to give some nearer views of representative specimens lying at different elevations on the main lake-belt, confining myself to descriptions of the features most characteristic of each.

SHADOW LAKE

This is a fine specimen of the oldest and lowest of the existing lakes.  It lies about eight miles above Yosemite Valley, on the main branch of the Merced, at an elevation of about 7350 feet above the sea; and is everywhere so securely cliff-bound that without artificial trails only wild animals can get down to its rocky shores from any direction.  Its original length was about a mile and a half; now it is only half a mile in length by about a fourth of a mile in width, and over the lowest portion of the basin ninety-eight feet deep.  Its crystal waters are clasped around on the north and south by majestic granite walls sculptured in true Yosemitic style into domes, gables, and battlemented headlands, which on the south come plunging down sheer into deep water, from a height of from 1500 to 2000 feet.  The South Lyell glacier eroded this magnificent basin out of solid porphyritic granite while forcing its way westward from the summit fountains toward Yosemite, and the exposed rocks around the shores, and the projecting bosses of the walls, ground and burnished beneath the vast ice-flood, still glow with silvery radiance, notwithstanding the innumerable corroding storms that have fallen upon them.  The general conformation of the basin, as well as the moraines laid along the top of the walls, and the grooves and scratches on the bottom and sides, indicate in the most unmistakable manner the direction pursued by this mighty ice-river, its great depth, and the tremendous energy it exerted in thrusting itself into and out of the basin; bearing down with superior pressure upon this portion of its channel, because of the greater declivity, consequently eroding it deeper than the other portions about it, and producing the lake-bowl as the necessary result.

With these magnificent ice-characters so vividly before us it is not easy to realize that the old glacier that made them vanished tens of centuries ago; for, excepting the vegetation that has sprung up, and the changes effected by an earthquake that hurled rock-avalanches from the weaker headlands, the basin as a whole presents the same appearance that it did when first brought to light.  The lake itself, however, has undergone marked changes; one sees at a glance that it is growing old.  More than two thirds of its original area is now dry land, covered with meadow-grasses and groves of pine and fir, and the level bed of alluvium stretching across from wall to wall at the head is evidently growing out all along its lakeward margin, and will at length close the lake forever.