Beyond this wood we found the Mirror Lake. It is a small pool, but exquisitely cradled in the very midst of stern granite giants, which stand all around as sentinels, guarding its placid sleep. Willows, already covered with downy tufts, and now just bursting into slender leaflets, fringe its shores, and tall cedars and pines overshadow its waters, and are therein reflected in the stillness of early dawn, when even the granite crags far overhead also find themselves mirrored in the calm lakelet. But with the dawn comes a whispering breeze; and just as the sun’s first gleam kisses the waters, the illusion vanishes, and there remains only a somewhat muddy and troubled pool.
It lies just at the base of that extraordinary Half-Dome of which I told you yesterday—a gigantic crest of granite, which rises above the lake almost precipitously to a height of 4,737 feet. Only think of it!—nearly a mile! Of this the upper 2,000 feet is a sheer face of granite crag, absolutely vertical, except that the extreme summit actually projects somewhat; otherwise it is as clean cut as if the mighty Dome had been cloven with a sword. A few dark streaks near the summit (due, I believe, to a microscopic fungus or lichen) alone relieve the unbroken expanse of glistening, creamy white.
The lower half slopes at a very slight incline, and is likewise a solid mass of granite—not made up of broken fragments, of which there are a wonderfully small proportion anywhere in the valley. So the inference is, that in the tremendous convulsion this mighty chasm was created, the great South Dome was split from the base to the summit, and that half of it slid down into the yawning gulf: thus the gently rounded base, between the precipice and the lake, was doubtless originally the summit of the missing half mountain.
I believe that geologists are now satisfied that this strange valley, with its clean-cut, vertical walls, was produced by what is called in geology “a fault,”—namely, that some of the earth’s ribs having given away internally, a portion of the outer crust has subsided, leaving an unoccupied space. That such was the case in Yo-semité, is proved by much scientific reasoning. It is shown that the two sides of the valley in no way correspond, so the idea of a mere gigantic fissure cannot be entertained. Besides, as the valley is as wide at the base as at the summit, the vertical walls must have moved apart bodily,—a theory which would involve a movement of the whole chain of the Sierras for a distance of a half a mile.
There is not trace of any glacier having passed through the valley, so that the Ice-giants have had no share in making it. Neither can it have been excavated by the long-continued action of rushing torrents, such as have carved great canyons in many parts of the Sierra Nevada. These never have vertical walls; and besides, the smoothest faces of granite in Yo-semité are turned towards the lower end of the valley, proving at once that they were never produced by forces moving downward.
So it is simply supposed that a strip of the Sierras caved in, and that in time the melting snows and streams formed a great deep lake, which filled up the whole space now occupied by the valley. In the course of ages the débris of the hills continually falling into the lake, must have filled up the chasm to a level with the canyon, which is the present outlet from the valley; and as the glaciers on the upper Sierras disappeared, and the water-supply grew less, the lake must have gradually dried up (and that in comparatively recent times), and its bed of white granite sand, mingled with vegetable mould, was transformed into a green meadow, through which the quiet river now glides peacefully.
This evening the sun set in a flood of crimson and gold—such a glorious glow as would have dazzled an eagle. It paled to a soft primrose, then ethereal green. Later, the pearly-grey clouds were rose-flushed by an afterglow more vivid than the sunset itself—a rich full carmine, which quickly faded away to the cold, intense blue of a Californian night. It was inexpressibly lovely.
Then the fitful wind rose in gusts—a melancholy, moaning wail, vibrating among rocks, forests, and waters, with a low, surging sound—a wild mountain melody.
No wonder the Indians reverence the beautiful Yo-semité Falls. Even the white settlers in the valley cannot resist their influence, but speak of them with an admiration that amounts to love. Some of them have spent the winter here, and seem almost to have enjoyed it.
They say that if I could see the falls in their winter robes, all fringed with icicles, I should gain a glimpse of fairyland. At the base of the great fall the fairies build a real ice-palace, something more than a hundred feet high. It is formed by the ever falling, freezing spray; and the bright sun gleams on this glittering palace of crystal, and the falling water, striking upon it, shoots off in showers like myriad opals and diamonds.