THE ORANGE CLIFFS. 173 
lilac colored rocks, very distinctly stratified. The dark red rocks are very 
hard, the chocolate and lilac are very soft, so below we have terraced and 
buttressed walls and huge blocks scattered about, which have fallen from 
the upper part of the escarpment. The homogeneous sandstone above is 
slowly undermined so slowly that, as the unsupported rocks yield to the 
force of gravity, fissures are fornied parallel to the face of the cliff. Trans 
verse vertical fissures are also formed, and thus the wall has a columnar 
appearance, like an escarpment of basalt, but on a giant scale; and it is 
these columns that tumble over at last, and break athwart into the huge 
blocks which are strewn over the lower terraces. 
The drainage of an inclined terrace is usually from the brink of the 
cliff toward the foot of the terrace above, i. e., in the direction of the dip 
of the strata. As the channels of these intermittent streams approach the 
upper escarpment, they turn and run along its foot until they meet with 
larger and more permanent streams, which run against the dip of the rock 
in a direction opposite the course of the smaller channels, and these latter 
usually cut either quite through the folds, or at least through the harder 
series of rocks which form the cliffs. 
In some places the waters run down the face of the escarpment, and cut 
narrow canons, or gorges, back for a greater or less distance into the cliffs, 
until what would, otherwise, be nearly a straight wall, is cut into a very 
irregular line, with salients and deep re-entering angles. 
These canons which cut into the walls also have their lateral canons 
and gorges, and sometimes it occurs that a lateral canon from each of two 
adjacent main canons will coalesce at their heads, and gradually cut off the 
salient cliff from the ever retreating line. In this way buttes are formed. 
The sides of these buttresses have the same structural characteristics as the 
cliffs from which they have been cut. So the buttes on the plains below the 
Orange Cliffs are terraced and buttressed below, and fluted and columned 
above. Often the upper parts of these buttes are but groups of giant 
columns. 
The three lines of cliffs, which I have thus described, have been traced 
to the east but a few miles back from the river. The way in which they 
terminate is not known ; but, from a general knowledge obtained from a 
