714 ALLEN DAVID HOLE 
ated channel of the stream for three-fourths of a mile above the 
highest of the deposits. 
WEST OF THE SOUTH BRANCH OF TURKEY CREEK 
On the southern end of the 1o,100-foot hill west of the south 
branch of Turkey Creek, glacial débris extends from 10,100 feet 
elevation down to the stream on the east. The surface here con- 
sists of arkose soil with numerous bowlders, some rounded and some 
angular. On the south side at about 10,000 feet elevation a 
bowlder of Potosi rhyolite, 18 feet in diameter, has distinct glacial 
striae on a part of its surface where it has been measurably pro- 
tected from weathering. Other Potosi rhyolite bowlders are found, 
one as much as 12 feet in diameter. 
About one mile east of south from this hill on a southwestward- 
facing slope an exposure of drift occurs at elevation about 10,100 
feet; the soil here also is arkose containing bowlders in variety, a 
few of which are striated. This area is continuous over the top of 
the ridge to the northeast, down to elevation about 10,000 feet. 
These deposits are classed as older drift because of (1) their 
topographical position, 300 feet above the edge of drift of the more 
recent epoch; (2) their composition, including large bowlders of 
Potosi rhyolite which is unknown in the more recent drift except in 
small fragments; and (3) the weathered character of the material 
as shown by the arkose soil. 
DIAMOND HILL, AND OTHER ADJACENT POINTS 
Deposits classed as older drift are found on Diamond Hill (Fig. 
15) and on other elevated points on the mesa between Big Bear 
Creek and Bilk Creek, as shown on the map (see Part I). The 
deposits in all these places so closely resemble each other in com- 
position and general appearance that it would be impossible to 
distinguish one from the other if all were transferred to one place. 
The one most noticeable characteristic common to all is the presence 
of rather irregular bowlders of Potosi rhyolite from 4 to 1o feet in 
diameter, the larger size being the more frequent. Besides the 
Potosi rhyolite, other varieties of rock commonly present are basalt, 
diorite, diorite-monzonite, Telluride, quartzite, feldspar porphyry, 
