254 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Ficure 13. 
The canyons of Ash creek, near Toquerville. 
(Fig. 13). Apparently Ash creek cut the latter canyon before the last 
faulting, although possibly after the premonitory upheaval. At the 
time of the faulting the lava sheet was bent and the creek was tipped 
out of its old channel to the recent one. Renewed cliffs are everywhere 
the rule, although the most striking examples are the far-reaching lines 
of the great Pink, White, Vermilion, and Chocolate terraces. 
Of the three processes — namely, the stripping of soft strata, the cutting 
of canyons, and the formation of cliffs — the first and last two are now in 
a state of great, perhaps maximum, efficiency, while the first is already 
almost completed. The combined result of the three is a region of 
strong contrasts, where the three elements — canyons, plains, and cliffs — 
are utterly different, and yet all in their freshness and nakedness bear 
the stamp of newness and of a dry climate. But this is not everywhere 
the case, for in the Colob plateau the ancient mature topography is still 
preserved, and acts as a foil to set off the new. Yet it is the latter that 
is impressive. Old slopes have been revived and steepened ; enormous 
tusks of massive red sandstone have been carved out of the once con- 
tinuous upland (Plate 1 B), and deep canyons marvellously narrow and 
steep have been sawed far into the depths of the plateau. One of these, 
that of LeVerkin creek, is so cleft-like that for several miles, where the 
depth is over fifteen hundred feet, only a narrow strip of sky thirty 
degrees wide can be seen, and sometimes this is reduced to fifteen 
degrees. In many places the walls overhang the tumbling brook at a 
height of several hundred feet, and forever prevent the sun from pene- 
trating to the cool depths, which, after the hot, verdureless glare of the 
lowland desert, seem ideal in their delightful dampness and abundance 
of vegetation. Often the bottom of the canyon is so narrow that pine 
trees, overturned by wind or flood, have not room to fall flat, but lie 
