196 EXPLORATION OF THE CANONS OF THE COLORADO. 
the walls of the Grand Canon of the Colorado, where it divides the twin 
plateaus. 
Having crossed the Western Kaibab Fault, the canon suddenly changes 
in character. The throw of the rocks being more than one thousand five 
hundred feet, we lose the granite, and the bed of the river is in the lemon 
colored rocks, and now for many miles the canon is comparatively straight, 
and the walls are much more regular. At the bottom we have the rusty 
beds, and then the lemon colored beds, and then the marble cliffs, and when 
we reach the summit of this limestone we find the same bench as above, 
under the Kaibab Plateau, but here it is wider, ranging from two or three 
hundred yards to two or three miles. Then comes a sloping, bright red 
terrace, and back of it the cliffs of the cherty limestone, with standing rocks 
on the brink. 
You can stand on the southwestern corner of the Kaibab Plateau, and 
look over this straight stretch of canon for sixty miles. There seems to be 
a valley enclosed with walls one thousand five hundred or two thousand 
feet high, five to ten miles in width, with a narrow, winding gorge down its 
center. 
A few lateral canons come in on either side; so the walls are broken 
here and there, but the general outline is well preserved. 
Just before the river wheels again to the south, in the second great 
bend, it passes the To-ro'-weap Fault, which extends across the canon. The 
rocks have dropped down about eight hundred feet, and let the homogeneous 
limestone nearly down to the water. The fissure of this fault has been the 
channel through which floods of lava have been forced from depths below 
into the upper world. 
Many volcanic cones are seen standing along the line of the fault, or 
on the branches of the fissure. One of these volcanic cones stands on the 
very brink of the canon, and is the one of which mention was made in the 
account of the exploration. 
Passing this, the course of the river is southward, and once more the 
channel enters the granite. At the very apex of this bend, Diamond Creek 
makes its contribution from the south, and it was here that Lieutenant Ives 
and Doctor Newberry came down to the depths of the Grand Canon. 
