In the last chapter of my book entitled “The Canyons of the Colorado” I
have described the Grand Canyon in the following terms:
The Grand Canyon is a gorge 217 miles in length, through which flows a
great river with many storm-born tributaries. It has a winding way, as
rivers are wont to have. Its banks are vast structures of adamant, piled
up in forms rarely seen in the mountains.
Down by the river the walls are composed of black gneiss, slates, and
schists, all greatly implicated and traversed by dikes of granite. Let
this formation be called the black gneiss. It is usually about 800 feet
in thickness.
Then over the black gneiss are found 800 feet of quartzites, usually in
very thin beds of many colors, but exceedingly hard, and ringing under
the hammer like phonolite. These beds are dipping and unconformable with
the rocks above. While they make but 800 feet of the wall or less they
have a geologic thickness of 12,000 feet. Set up a row of books aslant;
it is ten inches from the shelf to the top of the line of books, but
there may be three feet of the books measured directly through the
leaves. So these quartzites are aslant, and though of great geologic
thickness they make but 800 feet of the wall. Your books may have
many-colored bindings and differ greatly in their contents; so these
quartzites vary greatly from place to place along the wall, and in many
places they entirely disappear. Let us call this formation the
variegated quartzite.
Above the quartzites there are 500 feet of sandstones. They are of a
greenish hue, but are mottled with spots of brown and black by iron
stains. They usually stand in a bold cliff, weathered in alcoves. Let
this formation be called the cliff sandstone.
Above the cliff sandstone there are 700 feet of bedded sandstones and
limestones, which are massive sometimes and sometimes broken into thin
strata. These rocks are often weathered in deep alcoves. Let this
formation be called the alcove sandstone.
Over the alcove sandstone there are 1,600 feet of limestone, in many
places a beautiful marble, as in Marble Canyon. As it appears along the
Grand Canyon it is always stained a brilliant red, for immediately over
it there are thin seams of iron, and the storms have painted these
limestones with pigments from above. Altogether this is the red-wall
group. It is chiefly limestone. Let it be called the red-wall limestone.
Above the red wall there are 800 feet of gray and bright red sandstone,
alternating in beds that look like vast ribbons of landscape. Let it be
called the banded sandstone.
And over all, at the top of the wall, is the Aubrey limestone, 1,000
feet in thickness. This Aubrey has much gypsum in it, great beds of
alabaster that are pure white in comparison with the great body of
limestone below. In the same limestone there are enormous beds of chert,
agates, and carnelians. This limestone is especially remarkable for its
pinnacles and towers. Let it be called the tower limestone.
These are the elements with which the walls are constructed, from black
buttress below to alabaster tower above. All of these elements weather
in different forms and are painted in different colors, so that the wall
presents a highly complex façade. A wall of homogeneous granite, like
that in the Yosemite, is but a naked wall, whether it be 1,000 or 5,000
feet high. Hundreds and thousands of feet mean nothing to the eye when
they stand in a meaningless front. A mountain covered by pure snow
10,000 feet high has but little more effect on the imagination than a
mountain of snow 1,000 feet high—it is but more of the same thing—but a
façade of seven systems of rock has its sublimity multiplied sevenfold.
[Illustration: A Panoramic View of the Canyon.]
Consider next the horizontal elements of the Grand Canyon. The river
meanders in great curves, which are themselves broken into curves of
smaller magnitude. The streams that head far back in the plateau on
either side come down in gorges and break the wall into sections. Each
lateral canyon has a secondary system of laterals, and the secondary
canyons are broken by tertiary canyons; so the crags are forever
branching, like the limbs of an oak. That which has been described as a
wall is such only in its grand effect. In detail it is a series of
structures separated by a ramification of canyons, each having its own
walls. Thus, in passing down the canyon it seems to be inclosed by
walls, but oftener by salients—towering structures that stand between
canyons that run back into the plateau. Sometimes gorges of the second
or third order have met before reaching the brink of the Grand Canyon,
and then great salients are cut off from the wall and stand out as
buttes—huge pavilions in the architecture of the canyon. The scenic
elements thus described are fused and combined in very different ways.