The number of glaciers in the Alps, according to the Schlagintweit
brothers, is 1100, of which 100 may be regarded as primary, and the
total area of ice, snow, and _névé_ is estimated at 1177 square
miles, or an average for each glacier of little more than one square
mile. On the same authority, the average height above sea-level at which
they melt is about 7414 feet. The Grindelwald glacier descends below
4000 feet, and one of the Mont Blanc glaciers reaches nearly as low a
point. One of the largest of the Himalaya glaciers on the head waters of
the Ganges does not, according to Captain Hodgson, descend below 12,914
feet. The largest of the Sierra glaciers on Mount Shasta descends to
within 9500 feet of the level of the sea, which, as far as I have
observed, is the lowest point reached by any glacier within the bounds
of California, the average height of all being not far from 11,000 feet.

The changes that have taken place in the glacial conditions of the
Sierra from the time of greatest extension is well illustrated by the
series of glaciers of every size and form extending along the mountains
of the coast to Alaska. A general exploration of this instructive region
shows that to the north of California, through Oregon and Washington,
groups of active glaciers still exist on all the high volcanic cones of
the Cascade Range,--Mount Pitt, the Three Sisters, Mounts Jefferson,
Hood, St. Helens, Adams, Rainier, Baker, and others,--some of them of
considerable size, though none of them approach the sea. Of these
mountains Rainier, in Washington, is the highest and iciest. Its
dome-like summit, between 14,000 and 15,000 feet high, is capped with
ice, and eight glaciers, seven to twelve miles long, radiate from it as
a center, and form the sources of the principal streams of the State.
The lowest-descending of this fine group flows through beautiful forests
to within 3500 feet of the sea-level, and sends forth a river laden with
glacier mud and sand. On through British Columbia and southeastern