446 SIDNEY PAIGE 
In Fig. 2 the northeast and southwest sides of a low mountain 
range are shown with the Pleistocene gravel boundaries. Attention 
is called first to the proximity of the northeastern boundary to the 
crest line of the range, second, to the relatively straight boundary 
of the western gravels along whose entire course there is believed 
to exist a fault. The bench here exposed (though severely dissected 
by sharp canyons) is interpreted as the old floor upon which grave 
| once lay, and here again the gravel has 
N been removed because of its superior 
elevation. An interesting point is the 
narrowness of the mountain remnant if, 
in imagination, we restore the gravel to 
the bench. It shows clearly how nearly 
the mountain range escaped destruction. 
Fig. 3 shows a mountain core and 
gravel-free rock bench which slopes 
outward from the mountains and passes 
beneath a sheet of gravel. The bench 
is a striking physiographic feature. In 
this case special attention is called to 
the southeastern portion 
where the gravel has been 
cleanly swept from a por- 
eee tion of the bench. Al- 
ae though straight boundaries 
“<< between gravel-covered 
mene and gravel-free portions of 
Fic: 4 : the bench are not observed, 
there are geologic reasons 
for believing that there has been uplift, a movement sufficient to 
initiate removal of the gravel sheet and dissection of the bench. 
Fig. 4 shows a mountain mass with its surrounding gravel sheet. 
Note the straight fault contact on the southeastern side. The 
figure is somewhat analogous to Fig. 2 but the remains of any bench 
that may have existed is nearly or quite obliterated by recent 
cutting. The figure serves, however, to show, because of the fault, 
L2MILES | 
