22 
THE GRAND CAStON DISTRICT. 
be affirmed that none of any importance exist. They would not have 
escaped observation if they were present. 
In the course of the present work much use will be made of the drain- 
age system in the task of unraveling the geological history of the region, 
and a brief sketch of that system is deemed necessary here. The trunk of 
the drainage tree is the Colorado. This marvelous river, after traversing 
the heart of the Plateau Province for hundreds of miles, and nearly all the 
way in profound chasms, at length reaches the escarpment of the Echo 
Cliffs. Here it emerges for a moment from between opposing walls of im- 
pressive magnitude into a comparatively open space. But it is for a moment 
only. At once it begins to sink in the Carboniferous platform another 
chasm, termed the Marble Canon. The course of the river as it leaves 
the Echo Cliffs is southwest, and gradually it bends to due south. As its 
bed descends the strata slowly rise, and at the distance of 65 miles (as the 
river runs) from the Echo Cliffs the abyss attains a depth of 3,600 feet. At 
this point the Little Colorado, a tributary coming from the south, enters it 
through a canon of equal depth. Three or four miles from the confluence 
the main stream, hitherto flowing southward, suddenly changes its course 
to the west and enters the upward slope of the East Kaibab monocline. 
Rapidly the chasm deepens to about 6,000 feet — the increase of depth being 
mainly due to the fact that it penetrates a much higher country while the 
descent of the river meantime is immaterially small. Here begins the Grand 
Canon. On the north is the Kaibab Plateau, and on the south is the con- 
tinuation of the same platform as the Kaibab, at an altitude which is only 
three or four hundred feet lower — a difference which is very small in com- 
parison with the depth of the chasm. Through this lofty plateau — 8,000 
to 9,000 feet high — the chasm extends for a distance of about 60 miles, 
gradually changing its direction to the northwest. This portion of the 
canon will, for convenience of discussion, be called the Kaibab division of 
the Grand Canon. It is the sublimest portion of the chasm, being nearly a 
thousand feet deeper than any other. But the greater depth is by no means 
the chief reason for this superior grandeur, since the relative difference 
between 5,000 and 6,000 feet is not so very great. But the Kaibab division 
is far more diversified and complex than the others and is adorned with a 
