DAVIS: THE WASATCH, CANYON, AND HOUSE RANGES. 21 
are determined by the stronger and weaker strata run oblique to the 
well maintained north-south trend of the range as a whole. ‘This 
relation is roughly shown in figure 4, sketched near Mona, looking 
eastward. The lowest members of the series, A, A, form the base 
of the range on the left (north); these were taken to be the same 
beds that are mentioned above as appearing locally at the base of the 
range along the slightly convex base line between Spring Lake and 
Santaquin. Next comes a strong ridge, B, B, somewhat dissected by 
obsequent ravines on its outcrop face, and ending in small, slightly 
facetted spurs along the base line: this was taken to be made of the 
same series of darker strata which rose to the crest of the range next 
north of Santaquin. It is most significant to note the manner in 
which this ridge is obliquely cut off where it descends to the base 
line, so that it ends accordantly with the weaker strata that lie, strati- 
Fig. 4.— The oblique monocline of the Wasatch range, looking east from Mona: 
Mt. Nebo on the right; a landslide on the base line below. 
graphically, below and above it; instead of projecting farther forward 
into the plain, as it certainly should do if the mountain were not a 
fault block, moderately consumed by post-faulting erosion, but were 
the residual of a once much greater mass that had been worn back 
without any aid from faulting. Back of the oblique ridge is an 
oblique subsequent valley eroded along the strike of a belt of weaker 
strata, C, C, which thus determines location of a rather low pass in the 
range. The most curious feature about these weak strata is the 
small landslide of recent date, in which their incoherent materials 
have sprawled forth on the piedmont slope; it is the only case of 
the kind that has come under my observation on the Wasatch 
front, and it indicates that an uplift of the mountain block has here 
occurred so recently and so suddenly as still to be marked by the 
