178 
THE GEAND CAKON DISTEIOT. 
clence, predict the structure of the country many miles away, though no 
geologist has yet visited the locality. 
To the east we can see the chasm of the Little Colorado as it approaches 
its junction with the Marble Canon. Little of it is disclosed. An ordinary 
canon seldom is seen until we are close upon its brink, and the canon of the 
Little Colorado, though of very grand proportions, cannot be traced far, 
though we are more than 2,000 feet above the plain in which it is sunken. 
The place where it opens into the chasm of the Colorado is somewhat arbi- 
trarily chosen as marking the lower end of the Marble Canon and the head 
of the Grrand Canon. Here the Marble Canon descends from the north, and, 
after passing the junction of the Little Colorado, the main chasm begins to 
pass, by a gradual transition, into the features of the Grand Canon. The 
river sweeps around a long curve, changing its course to the westward, and 
enters the rising slope of the East Kaibab monocline. Through a distance 
of about ten miles from the junction the walls steadily rise more than two 
thousand feet higher, the abyss widens greatly, and the buttes, promonto- 
ries, amphitheaters, and side gorges make their appearance. 
The havoc wrought by erosion upon the slope of the monocline is 
extreme. Here the chasm is wider than at any other place, and the terrible 
scoring by side gorges is at its maximum. Owing to the greatly inclined 
attitudes of the strata the resulting forms are no longer beautiful, but shape- 
less and grotesque. The whole Carboniferous system has been cut away 
from the monocline just east of the point, and the lower rocks are laid bare. 
And these lower rocks, from a purely stratigraphic point of view, are extremely 
interesting. To these we now turn our attention. 
THE GEEAT UNCOHFOEMITY. 
The Carboniferous series, 4,000 to 4,500 feet in thickness, is throughout 
this region perfectly conformable, so far as appearances go, from top to 
bottom. The lowest conformable group consists of a series of thinly 
bedded sandstones or quartzites, with a total thickness of about 180 to 200 
feet. They have already been spoken of as exceedingly obdurate in charac- 
