CLIFFS OF DISPLACEMENT AND EEOSION. 191 
or, if we are to consider the displacement as caused by upheaval, the blocks 
uplifted have their lines of cliffs set farther back to the north; and the 
amount of this .backward or forward displacement is in direct ratio to the 
amount of vertical displacement in the fault or monoclinal fold. The higher 
region has suffered a greater amount of erosion, and as erosion progresses 
chiefly by undermining, as I have explained in the discussion of the Terrace 
Canons, the cliffs of the higher blocks stand farther back from the axis of 
upheaval than those of the lower blocks. 
The general line of these cliffs is broken in another way. Streams, 
heading on the high plateaus to the north, run southward into the Grand 
Canon, and have carved out canons through the cliffs, and turned the escarp 
ment far back into the several benches, so that instead of four unbroken 
walls facing the south, and having an easterly and westerly direction, we 
have, in fact, a series of salients and re-entering angles. 
Entering this country from the east or west, it is necessary to climb 
great benches, due to displacements along faults, and crossing it from south 
to north, it is necessary to climb great benches, but these are due to erosion; 
so we have two systems of cliffs cliffs of displacement, having a northerly 
and southerly trend, and cliffs of erosion, having an easterly and westerly 
trend. 
The first cliffs of displacement are of two classes: those facing the 
west, where the throw of the beds is on the western side of the fracture, and 
those facing the east, where the throw of the beds is on the eastern side of 
the fracture. 
The cliffs of erosion are very irregular in direction, but somewhat con 
stant in vertical outline; and the cliffs of displacement are somewhat regular 
in direction, but very inconstant in vertical outline. This inconstancy is 
due to the frequent changes in the character of the faults, which I have 
previously described. 
In the Echo Cliffs, east of Marble Canon, a line of cliffs, due to ero 
sion, and a slope due to displacement, have come together, back to back. 
The position of the slope is essentially unchangeable, as it is due to a 
flexure; but the escarpment, due to erosion, has doubtless been carried back 
from Marble Canon to the east, until it has just reached this .slope. Figure 
