DENVER & RIO GRANDE WESTERN ROUTE. 199 
Beyond Cisco the railroad curves here and there over the shale 
upland, steadily approaching the foot of the Book Cliffs, (See 
sheet 8, p. 210.) As it nears the cliffs it seems to be lost in a maze of 
smal] shale hills, as shown in Plate LXXXII, B, but in places one 
may catch glimpses through them of the ragged front of the cliffs. 
Viewed from a distance the Book Cliffs look like a regular mountain 
front, but viewed near by they are seen to be made up of a series of 
terraces or benches, each bench being formed by some hard bed of 
sandstone more resistant to erosion than the beds above or below. 
Each bench is cut by streams into a number of salients, or teeth, 
which project far beyond the main mass of the cliffs. Behind and 
above the lowest row of salients there may be a second row, formed 
Ficurn 53.—Mountains carved from a laccolith. The block at the rear ee ; euuaailat 
position of the sedimentary beds after they were forced upward by the in 
the Java. 
by a similar hard bed, and in places there is a still higher row of 
salients, formed by a third hard bed. The resulting cliffs pete 
® front that is very irregular in detail but very regular when view f 
from a distance. A view along the front, showing the lower tier o 
salients, is given in figure 54. The lowest bench of the pits Is 
formed by the lowest sandstone in the coal-bearing Mesaver * This 
mation, and the slope below is composed of Mancos shale. ae 
le is very homogeneous in composition, and therefore oaakR of 
Slopes it has been cut by many minute ravines, with a wea 
: ” ; one cist . Lac- 
the hardened lava is more resistant , lith”), meaning st ai i. the 
t 
On 
of formation Gilbert p fo | 
them the name “ laccolite” (which | has been carved from a laccolith is rep- 
was afterward changed to “lacco- | resented in figure 53. 
