206 BULLETIN: MUSEUM GF COMPARATIVE ZOOLOGY. 
shaped hill, splitting at its southern end so as to surround a long 
amphitheatre (Plate 2 B). 
In Bellevue ridge, where the series from Aubrey to Kanab are tipped 
up rather steeply with an eastward dip, the Shinarump forms a sharp 
monoclinal ridge or cuesta (see Fig. 3). We climbed this ridge near 
Dry canyon. From the base of the Hurricane, up through the super- 
Aubrey and Moencopie formations, the general slope was never far from 
thirty degrees, though it was broken occasionally by minor ridges and 
hollows, where harder members of the Moencopie showed their edges or 
softer ones had worn away. Toward the top of the shales, however, the 
slope became steeper and more difficult to climb, until on reaching the 
FIGureE 3. 
Bellevue ridge near Dry canyon. 
Shinarump we found a high cliff that could be scaled only in a few 
places. Along the greater part of this Shinarump edge, the hard con- 
glomerate projected out over the shale talus, showing how active was 
the sapping process beneath it. Eastward from the crest there was a 
long back-slope, down the top of the conglomerate, to a longitudinal _ 
valley that had been worn out on the overlying sandy shales. 
The Painted Desert formation is a series of shales, elsewhere chiefly 
clay-shales, but in the Toquerville district more sandy. Although 
varied in color, they are uniformly weak. Along the Vermilion cliffs, 
and particularly in the canyons, where revived erosion is most active, 
the rapid retreat of the shales has induced a general undermining of the 
overlying hard Kanab sandstone, giving a hummocky landslide topog- 
raphy that is quite different from any other surface form in the region. 
