form half a hundred rivers beset with cataracts; half a hundred roaring
rivers unite to form the Colorado, which rolls, a mad, turbid stream,
into the Gulf of California.

Consider the action of one of these streams. Its source is in the
mountains, where the snows fall; its course, through the arid plains.
Now, if at the river's flood storms were falling on the plains, its
channel would be cut but little faster than the adjacent country would
be washed, and the general level would thus be preserved; but under the
conditions here mentioned, the river continually deepens its beds; so
all the streams cut deeper and still deeper, until their banks are
towering cliffs of solid rock. These deep, narrow gorges are called
canyons.

For more than a thousand miles along its course the Colorado has cut for
itself such a canyon; but at some few points where lateral streams join
it the canyon is broken, and these narrow, transverse valleys divide it
into a series of canyons.

The Virgen, Kanab, Paria, Escalante, Fremont, San Rafael, Price, and
Uinta on the west, the Grand, White, Yampa, San Juan, and Colorado
Chiquito on the east, have also cut for themselves such narrow winding
gorges, or deep canyons. Every river entering these has cut another
canyon; every lateral creek has cut a canyon; every brook runs in a
canyon; every rill born of a shower and born again of a shower and
living only during these showers has cut for itself a canyon; so that
the whole upper portion of the basin of the Colorado is traversed by a
labyrinth of these deep gorges.

Owing to a great variety of geological conditions, these canyons differ