He has seen the snow descending in avalanches, but concludes
this cannot be the work of snow, for he finds it where no avalanches
occur. Nor can water have done it, for he sees this smoothness glowing
on the sides and tops of the highest domes. Only the winds of all the
agents he knows seem capable of flowing in the directions indicated by
the scoring. Indians, usually so little curious about geological
phenomena, have come to me occasionally and asked me, "What makeum the
ground so smooth at Lake Tenaya?" Even horses and dogs gaze wonderingly
at the strange brightness of the ground, and smell the polished spaces
and place their feet cautiously on them when they come to them for the
first time, as if afraid of sinking. The most perfect of the polished
pavements and walls lie at an elevation of from 7000 to 9000 feet above
the sea, where the rock is compact silicious granite. Small dim patches
may be found as low as 3000 feet on the driest and most enduring
portions of sheer walls with a southern exposure, and on compact
swelling bosses partially protected from rain by a covering of large
boulders. On the north half of the range the striated and polished
surfaces are less common, not only because this part of the chain is
lower, but because the surface rocks are chiefly porous lavas subject to
comparatively rapid waste.
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