It appears, therefore, that shadows in great part determine not only the
forms of lofty ice mountains, but also those of the snow banners that
the wild winds hang upon them.
Earthquake Storms
The avalanche taluses, leaning against the walls at intervals of a mile
or two, are among the most striking and interesting of the secondary
features of the Valley. They are from about three to five hundred feet
high, made up of huge, angular, well-preserved, unshifting boulders, and
instead of being slowly weathered from the cliffs like ordinary taluses,
they were all formed suddenly and simultaneously by a great earthquake
that occurred at least three centuries ago. And though thus hurled into
existence in a few seconds or minutes, they are the least changeable of
all the Sierra soil-beds. Excepting those which were launched directly
into the channels of swift rivers, scarcely one of their wedged and
interlacing boulders has moved since the day of their creation; and
though mostly made up of huge blocks of granite, many of them from ten
to fifty feet cube, weighing thousands of tons with only a few small
chips, trees and shrubs make out to live and thrive on them and even
delicate herbaceous plants--draperia, collomia, zauschneria, etc.,
soothing and coloring their wild rugged slopes with gardens and groves.
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