by the wearing away of
its shores, is well known, but in these icy regions of Alaska, and even
as far south as Vancouver Island, the coast rocks have been so short a
time exposed to wave-action they are but little wasted as yet. In these
regions the extension of the sea effected by its own action in
post-glacial time is scarcely appreciable as compared with that effected
by ice-action.

Traces of the vanished glaciers made during the period of greater
extension abound on the Sierra as far south as latitude 36 deg.. Even the
polished rock surfaces, the most evanescent of glacial records, are
still found in a wonderfully perfect state of preservation on the upper
half of the middle portion of the range, and form the most striking of
all the glacial phenomena. They occur in large irregular patches in the
summit and middle regions, and though they have been subjected to the
action of the weather with its corroding storms for thousands of years,
their mechanical excellence is such that they still reflect the sunbeams
like glass, and attract the attention of every observer. The attention
of the mountaineer is seldom arrested by moraines, however regular and
high they may be, or by canons, however deep, or by rocks, however noble
in form and sculpture; but he stoops and rubs his hands admiringly on
the shining surfaces and trios hard to account for their mysterious
smoothness. 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 protect