CHAPTER XII. 
THE PHYSICAL FEATURES OF THE VALLEY OF THE COLORADO, CONTINUED. 
In the previous chapter, I have made frequent mention of long lines of 
cliffs, or escarpments, extending across the Colorado, far back into the 
country on either side. I have attempted to explain the origin of these 
cliffs, as well as the origin of canons, as due to the erosion of greater or 
smaller folds of the stony formations, or beds of rock. To explain the chief 
characteristics of the Grand Canon, and the adjacent country, it is neces 
sary to describe other lines of cliffs, due to other causes. 
CLIFFS AND SLOPES OF DISPLACEMENT. 
The geological formations, or beds of rock, exposed in the Grand Cailon 
and the tributary gorges, have been fractured, or folded, on an extensive 
scale. These great fractures, or folds, extend across the canon in a northerly 
and southerly direction, and can be traced for scores of miles on either side 
not as huge cracks, or chasms, for they are observable only to the eye of 
the geologist, and are traced by the high steps and great displacements seen 
along their courses. Along these fractures we find what geologists call 
faults, i. e., the beds have fallen down on one side of each crack. This dis 
placement, or throw of the fault, as it is technically called, is from one or two 
hundred to two or three thousand feet, and is always noticed to be quite 
variable along any particular fault which may be studied. 
Let us try to obtain a well defined conception of such a fault. Sup 
pose that a fracture should be formed, extending from the shore of Lake 
Erie, in the northwest corner of Pennsylvania, diagonally through the State 
to the head of Delaware Bay a great crack, through the underlying rocks, 
to unknown depths below and that the country on the southwestern side 
