a centre for explosive eruptions, which
were extremely violent at one time. The islands which rise in the
lake are shattered, while Black Point, upon the northern shore,
has been uplifted by an explosion from beneath, which split the
rocks apart and formed deep fissures.

It is an interesting fact that in the Cordilleran region the mountains
have been increasing in height in very recent years. We might almost
say that they are growing to-day. In this region, then, we can
actually see how mountains are made; we do not have to depend upon
descriptions of the manner in which they are supposed to have been
made thousands of years ago.

[Illustration: FIG. 22.--BLUFF FORMED BY AN EARTHQUAKE

At the foot of the Wasatch Range, Utah]

Any good map will show that the mountains of the Cordilleran region
have in general a north and south direction. Their direction was
determined by fissures formed long ago in the crust of the earth.
Movements have continued to take place along many of these fissures
up to the present time, and probably will continue for some time
to come.

In order to become better acquainted with these remarkable mountains,
let us examine some of them, taking first the Wasatch Range in
eastern Utah. The range has an elevation of nearly eleven thousand
feet, rising gradually upon the eastern side, but presenting a bold
and picturesque front upon the west, toward the plain of Great
Salt Lake. A short drive from Salt Lake City brings us to the foot
of the range, at the mouth of Little Cottonwood Canon.

A peculiar bluff which extends for a number of miles along the
base of the mountains at once attracts our attention. The steep
face of the bluff, which is from fifty to seventy-five feet high,
appears to have been formed by a rising of the land upon the side
next the mountains, or a dropping upon the valley side. There are
reasons for believing that the formation of the bluff was due to
the occurrence of an earthquake some time within the last century.
The bluff is closely related to the mighty mountains behind it. It
was formed by the last of a series of movements in the earth which
raised the great block known as the Wasatch Range to an elevation
of six thousand feet above the plains at its base. Is it to be
wondered at that disturbances of the earth which result in the
erection of mountains of such height are frequently so severe as
to destroy the strongest buildings?

Now let us go westward across the