41 gives the larger part of it. In the basin there
are also great mountain masses, the fountainheads of the waters which
have carved the canyons. These are Uinta, Zuni, San Francisco, Henry,
Pine Valley, Uinkaret, Beaver Dam, Virgen, Navajo, La Sal, and others,
some reaching an altitude of more than twelve thousand feet. The highest
peaks of these, and of course those of the Continental Divide on the
east, which furnish a large proportion of the water of the Colorado,
and the Wind River Mountains on the extreme north, have snow-banks
throughout the summer. To show how dependent the Colorado is on the high
peaks for its flood-waters, I will mention that it is not till the snows
of these high altitudes are fiercely attacked by the sun in May and June
that the river has its annual great rise. It would take only a slight
lowering of the mean annual temperature now to furnish these peaks with
ice caps. The rainfall in the lower arid regions is from three to ten
inches, increasing northward to fifteen and twenty-five. On the peaks,
of course, it is much greater. Almost any climate can be had, from the
hot arid to the wet frigid. On the lower stretches, from Mohave down,
the thermometer in summer stands around 112 degrees F. a great deal of
the time, and reaches 118 degrees F. Yet Dr. Coues said he felt it no
more than he did the summer heat of New York or Washington.* In winter
the temperature at the bottom of the Grand Canyon is very mild, and
flowers bloom most of the time. One November I descended from the
snow-covered top of the Kaibab to the Grand Canyon at the mouth of the
Kanab, where I was able to bathe in the open air with entire comfort.

* I was at the Needles one summer for a brief time, and the air
seemed very oppressive to me.

There are six chief topographical features, canyons, cliffs, valleys,
mesa plateaus, high plateaus, mountains. There are two grand divisions:
the lowland or desert, below the Virgen, and the plateau, but the
topography of the immediate river course separates itself into four
parts, the Green River Valley, the canyon, the valley-canyon, and the
alluvial. The canyon part is the longest, occupying about two-thirds of
the whole, or about 1200 miles. It is cut mainly through the plateaus.
The last of these southward is the Colorado, a vast upheaval reaching
from the lower end of the Grand Canyon south-east to about where the
34th parallel crosses the western line of New Mexico. Lieuten