170 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
For the greater part of the range front, the fans that spread forward 
from the ravines are not faulted, but near the junction of the southern 
and middle blocks, subrecent and recent faulting is conspicuous. The 
most interesting locality is near 
ne Som Hollis’s ranch, Figure 18. Here 
lee 2 aang ee several strong bluffs rise rather 
boldly from the plain, forming ter- 
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minal escarpments to spurs whose 
interstream surface, 600 or 800 feet 
over the mountain base, seems to 
have been well graded and reduced 
to small relief before it was cut by 
the streams that are now eroding 
sharp ravines in it; but the same 
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2 streams run forward on aggraded 
DS < gravel fans east of the mountain base 
“4 line. The blufis between the streams 
occasionally show outcropping ledges, 
but most of the bluff face is an even 
slope of slide-rock at an angle near 
35°. Just north of Hollis’s ranch, 
E = the bluff must be nearly 1,000 feet 
Figure 18. high, but it rapidly diminishes in 
Rough map around Hollis’s ranch. The strength north and south; and a mile 
eee belt five or six miles; and a half or two miles from the 
highest part of the bluff, the moun- 
tain base is of the usual gentle expression. The largest stream that cuts 
the bluff has a sharp-cut gorge next north of Hollis’s ranch, whose irri- 
gated fields lie on the fan that the stream has built. Very recent fault- 
ing is indicated by fragments of an older fan, now standing about 150 
or 200 feet above the present fan on either side of the canyon mouth. 
Next north and south there are two “hanging valleys,” 500 or 600 feet 
over the plain, the like of which was not noted elsewhere along the 
Stein mountain front. 
Some of these local features might be explained, independent of fault- 
ing, by the occurrence of a mass of unusually resistant rock at this part 
of the mountain base; but in that case it might be expected that a 
greater number of outcrops would be seen on the bluff faces and in the 
ravine walls. As far as the rock was examined, it seemed to be a 
porphyritic andesite, similar to other lavas of the mountain block. 
. 
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