of Alaska enormous glaciers reach down to the sea.

A glacier worthy of our study may be found upon the Three Sisters,
a group of lofty and picturesque volcanic mountains rising from
the summit of the Cascade Range in central Oregon. There is a deep
depression between two of the peaks, which slopes down to the north
and is thus particularly well adapted to catch and retain the drifting
snows. Consequently the glacier to which it gives rise is of exceptional
size, being nearly three miles long and half a mile wide.

[Illustration: FIG. 16.--THE THREE SISTERS, FROM THE NORTH

Showing snow-fields and glacier. Fields of recent lava appear in
the foreground]

The easiest path to the Three Sisters is by way of the McKenzie
River from Eugene, Oregon. The McKenzie is a noted stream and one
of the most beautiful in the state. The river courses through dense
forests, and its clear, cold water is filled with trout. So tempestuous
is the weather about the Cascade range that July is almost the only
month in which one can visit the Three Sisters without danger of
being caught in severe storms.

The traveller leaves the river a few miles above McKenzie Bridge,
where a small tributary known as Lost Creek joins it. Lost Creek
flows under the lava from a lake near the Three Sisters, while
another stream, coming from the glacier of which we are in search,
flows down the same valley upon the surface of the lava and almost
directly over the hidden stream.

Upon the summit of the Cascade Range the dense forests of the river
valley give place to more open woods interspersed with park-like
meadows. A few miles away to the south rise the volcanic peaks of
the Three Sisters, clear and cold in the mountain air, wrapt about
with a mantle of white except where the slopes are too precipitous
to hold the snow.

An indistinct trail leads through the tamarack forest and over a
field of rugged lava to the base of the peaks. Here we come upon
a swiftly flowing stream of a strange milky color. This appearance
is due to the presence of fine mud, the product of the work of the
glacier at the head of the stream as it slowly and with mighty
power grinds away the surface of the rocks over which it moves.
Wherever one meets a stream of this kind, he will probably be safe
in asserting that it is fed by a glacier upon some distant mountain
peak.

This little stream, the course of which we must follow to reach
the glacier, is choked with sand and pebble