Titan of Chasms: The Grand Canyon of ArizonaPowell, John Wesley
History
Titan of Chasms: The Grand Canyon of Arizona
Powell, John Wesley
Grand Canyon (Ariz.)
The whole scene is forever reminding you of mighty architectural
pinnacles and towers and balustrades and arches and columns with lattice
work and delicate carving. All of these architectural features are
sublime by titanic painting in varied hues—pink, red, brown, lavender,
gray, blue, and black. In some lights the saffron prevails, in other
lights vermilion, and yet in other lights the grays and blacks
predominate. At times, and perhaps in rare seasons, clouds and cloudlets
form in the canyon below and wander among the side canyons and float
higher and higher until they are dissolved in the upper air, or perhaps
they accumulate to hide great portions of the landscape. Then through
rifts in the clouds vistas of Wonderland are seen. Such is that portion
of the canyon around the great south bend of the Colorado River past the
point of the Kaibab Plateau.
As Seen by the Geologist
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.
Public-domain text, read in full here on John Shaqi.
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