at the foot
of the mountains on the east and the west high on their flanks,
7000-10,000 ft. above the sea. Between 36 deg. 20' and 38 deg. the
lowest gap of any kind is above 9000 ft., and the average height of
those actually used is probably not less than 11,000 ft. The Kearsarge,
most used of all, is still higher. Very few in the entire Sierra are
passable by vehicles. Some forty peaks are catalogued between 5000 and
8000 ft., and there are eleven above 14,000. The highest portion of the
system is between the parallels of 36 deg. 30' and 37 deg. 30'; here the
passes are about 12,000 ft. in elevation, and the peaks range from
13,000 ft. upward, Mount Whitney, 14,502 ft., being the highest summit
of the United States, excluding Alaska. From this peak northward there
is a gradual decline, until at the point where the Central Pacific
crosses in lat. 39 deg. 20' the elevation is only 7000 ft.

Of the mountain scenery the granite pinnacles and domes of the highest
Sierra opposite Owen's Lake, where there is a drop eastward into the
valley of about 10,000 ft. in 10 m.; the snowy volcanic cone of Mt
Shasta, rising 10,000 ft. above the adjacent plains; and the lovely
valleys of the Coast Range, and the south fork of the King river--all
these have their charms; but most beautiful of all is the unique scenery
of the Yosemite Valley (q.v.). Much of the ruggedness and beauty of the
mountains is due to the erosive action of many alpine glaciers that once
existed on the higher summits, and which have left behind their
evidences in valleys and amphitheatres with towering walls, polished
rock-expanses, glacial lakes and meadows and tumbling waterfalls.
Remnants of these glaciers are still to be seen,--as notably on Mt.
Shasta,--though shrunk to small dimensions. Glacial action may be
studied well as far south as 36 deg. The canyons are largely the work of
rivers, modified by glaciers that ran through them after the rivers had
formed them. All of the Sierra lakes and ponds are of glacial origin and
there are some thousands of them. The lower lake line is about 8000 ft.;
it is lower to the north than to the south, owing to the different
climate, and the different period of glacial retrogression. Of these
lakes some are fresh, and some--as those of the north-east
counties--alkali. The finest of all is Tahoe, 6225 ft. above the sea,
lying between the true Sierras and the Basin Ranges, with peaks on
several sides rising 4000-5000 ft. above