J. W. Powell—Types of Orographie Structure. 421 
displacement in a horizontal position ; but every block is tilted 
more or less, and often a valley appears at the foot of the slope, 
and the streams which head on the opposite brink of the pla- 
teau have excavated valleys, leaving intervening ridges which 
project into the valley, having an effect somewhat like that 
described as one of the concomitant forms of the Uinta structure. 
6. Cliffs of Hrosion.—An inclined plateau may be bounded 
on the upheaved side by an escarpment of erosion, and such an 
escarpment is gradually carried back by an undermining pro- 
cess irom the line of greatest upheaval. The drainage of such 
a plateau is usually from the brink of this escarpment toward 
the valley on the opposite side; yet a minor drainage is found 
which carves out deep gulches, and the cliffs of erosion have 
deep reéntrant and sharp salient angles. 
7. uttes.—Sometimes the gulches which form the deep, 
reentrant angles of a line of cliffs have lateral gulches, which 
by continued erosion coalesce, and the salient angles are grad- 
ually cut off from the escarpment, which is ever retreating. In 
this manner buttes are formed as outliers of cliffs. 
- Cameo Mountains.—W herever considerable areas of hori- 
zontal or nearly horizontal strata are found sufficiently elevated 
great beauty. This is especially the case where the beds are of 
different texture and color, when the mountains will be ter- 
taced and buttressed in beautiful regularity, and banded with 
the colors which are characteristic of the several beds of which 
they are composed. ‘ 
few miles north of the Uinta Mountains, on the west side 
of the Green River, a group of such mountains is found, to 
which T have given the name Cameo Mountains, and I call this 
the Cameo structure. 
V. Basin Range Structure. 
When the blocks into which a district of country has been 
broken by faults are greatly tilted so that the strata dip at high 
