One cannot look upon Yosemite or walk beneath its towering walls
without the question arising in his mind, How did all this happen?
What were the agents that brought it about? There has been a great
geologic drama enacted here; who or what were the star actors? There
are two other valleys in this part of the Sierra, Hetch-Hetchy and
King's River, that are almost identical in their main features,
though the Merced Yosemite is the widest of the three. Each of them
is a tremendous chasm in the granite rock, with nearly vertical
walls, domes, El Capitans, and Sentinel and Cathedral Rocks, and
waterfalls--all modeled on the same general plan. I believe there
is nothing just like this trio of Yosemites anywhere else on the
globe.
Guided by one's ordinary sense or judgment alone, one's judgment as
developed and disciplined by the everyday affairs of life and the
everyday course of nature, one would say on beholding Yosemite that
here is the work of exceptional and extraordinary agents or
world-building forces. It is as surprising and exceptional as would
be a cathedral in a village street, or a gigantic sequoia in a grove
of our balsam firs. The approach to it up the Merced River does not
prepare one for any such astonishing spectacle as awaits one. The
rushing, foaming water amid the tumbled confusion of huge granite
rocks and the open V-shaped valley, are nothing very remarkable or
unusual. Then suddenly you are on the threshold of this hall of the
elder gods. Demons and furies might lurk in the valley below, but
here is the abode of the serene, beneficent Olympian deities. All is
so calm, so hushed, so friendly, yet so towering, so stupendous, so
unspeakably beautiful. You are in a mansion carved out of the
granite foundations of the earth, with walls two or three thousand
feet high, hung here and there with snow-white waterfalls, and
supporting the blue sky on domes and pinnacles still higher. Oh, the
calmness and majesty of the scene! the evidence of such tremendous
activity of some force, some agent, and now so tranquil, so
sheltering, so beneficent!
That there should be two or three Yosemites in the Sierra not very
far apart, all with the main features singularly alike, is very
significant--as if this kind of valley was latent in the granite of
that region--some peculiarity of rock structure that lends itself
readily to these formations. The Sierra lies beyond the southern
limit of the great continental ice-sheet of late Tertiary times, but
it nursed and reared many local glaciers, and to the eroding power
of these its Yosemites are partly due. But water was at work here
long before the ice--eating down into the granite and laying open
the mountain for the ice to begin its work. Ice may come, and ice
may go, says the river, but I go on forever. Water tends to make a
V-shaped valley, ice a U-shaped one, though in the Hawaiian Islands,
where water erosion alone has taken place, the prevailing form of
the valleys is that of the U-shaped. Yosemite approximates to this
shape, and ice has certainly played a part in its formation. But the
glacier seems to have stopped at the outlet of the great valley; it
did not travel beyond the gigantic hall it had helped to excavate.
The valley of the Merced from the mouth of Yosemite downward is an
open valley strewn with huge angular granite rocks and shows no
signs of glaciation whatever. The reason of this abruptness is quite
beyond my ken. It is to me a plausible theory that when the granite
that forms the Sierra was lifted or squeezed up by the shrinking of
the earth, large fissures and crevasses may have occurred, and that
Yosemite and kindred valleys may be the result of the action of
water and ice in enlarging these original chasms. Little wonder that
the earlier geologists, such as Whitney, were led to attribute the
exceptional character of these valleys to exceptional and
extraordinary agents--to sudden faulting or dislocation of the
earth's crust. But geologists are becoming more and more loath to
call in the cataclysmal to explain any feature of the topography of
the land. Not to the thunder or the lightning, to earthquake or
volcano, to the forces of upheaval or dislocation, but to the still,
small voice of the rain and the winds, of the frost and the
snow,--the gentle forces now and here active all about us, carving
the valleys and reducing the mountains, and changing the courses of
rivers,--to these, as Lyell taught us, we are to look in nine cases
out of ten, yes, in ninety-nine out of a hundred, to account for the
configuration of the continents.
The geologists of our day, while not agreeing as to the amount of
work done respectively by ice and water, yet agree that to the
latter the larger proportion of the excavation is to be ascribed. At
any rate between them both they have turned out one of the most
beautiful and stupendous pieces of mountain carving to be found upon
the earth.