46 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
There is evidence of a still stronger transverse fault in the northern 
part of the Sawtooth mass, for after the heavy gray-and-slate colored 
limestones of the Smoothback mass have pitched southward and dis- 
appeared, the next strata farther south, just before the granite is 
reached, are reddish quartzitic beds, which elsewhere were noted only 
beneath the limestones. Unfortunately we had not time to make a 
careful northwest-southeast section across the questionable district, 
by which such a fault could be easily determined. 
The West-jacing Escarpment of the House Range. The range thus 
described is believed to be a tilted and dissected fault block, chiefly 
because its western escarpment and baseline are comparatively con- 
tinuous and of moderate curvature, although they traverse a variety 
of structures; and because a number of rock masses, peculiarly de- 
Fia. 23.— Displaced knob of gray-and-slate limestones, in the notch of the 
northern road; looking northwest; Tule flats and the Deep creek range in 
the distance. 
formed and out of place, occur in the piedmont slope beneath the 
escarpment. The dissection of the fault block has progressed much 
farther than the dissection of the Wasatch range, and about as far 
as that of the Canyon range. 
With regard to the west-facing escarpment, it might, as already 
suggested, be explained in the Swazy mass as the riormasllj retreating 
face of a monoclinal structure w hich once extended much farther 
westward, provided that a series of sufficiently weak strata was found 
along its base. But if this were the true explanation, the escarpment 
should persistently follow the strike of the cliff-making limestones; 
it should turn to the southwest at the southern part of the Smoothback 
mass, where the dip changes from eastward to southeastward. Simi- 
larly, the strata in the strong northeast-southwest escarpment, by 
