192 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
5. SIERRA COUNTY. 
Rocks collected and described by H. W. Turner. See paper in 17th 
Ann. , Part I, p. 521. Additional details, supplied by Turner, are given 
here. Analyses A to H by W. F. Hillebrand, record Nos. 1456 and 
1548. Analysis I by H. N. Stokes, record No. 1514. 
A. Granulite (aplite), Yuba Gap, road east of Sierra Buttes. Con- 
tains orthoclase, microcline, quartz, plagioclase, some shreds of green- 
ish mica, and a little iron ore, chlorite, and apatite. P. R. C. 730. 
B. Granulite (aplite), dike east of Milton. Contains orthoclase, 
quartz, plagioclase, a little microcline, brown mica, and iron ore. P. 
R. C. 734. 
C. Biotite-quartz-monzonite, Indian Valley. Contains plagioclase, 
orthoclase, quartz, brown mica, apatite, and iron ore. P. R. C. 737. 
D. Quartz-diorite-porphyry, dike in Indian Valley granite. Con- 
tains plagioclase, hornblende, biotite, and quartz. P. R. C. 738. 
E. Quartz-mica-diorite, large area east of Milton. Contains plagio- 
clase, a turbid feldspar which is apparently not orthoclase, quartz, 
green hornblende, brown mica, iron ore, and apatite. P. R. C. 732. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na/) 
K 2 
H 2 at 100° . . . . 
H 2 above 110° 
Ti0 2 
PA 
MnO 
SrO 
BaO 
Li 2 
76.03 
13.39 
.48 
.31 
.05 
1.28 
2.98 
5.18 
.15 
.34 
.07 
.03 
trace 
trace 
.04 
none 
100. 33 
B. 
75.97 
13.07 
.61 
.39 
.14 
1.49 
2.51 
5.62 
.14 
.24 
.09 
trace 
trace 
.03 
.14 
trace 
100. 44 
68.65 
16.34 
.93 
1.48 
1.29 
3.07 
4.85 
1.85 
.24 
.62 
.28 
.15 
.08 
.07 
.09 
trace 
99.99 
66.65 
17.61 
.93 
1.67 
1.26 
4.44 
4.59 
1.70 
.03 
.41 
.33 
.18 
.07 
.12 
trace 
99. 
57.26 
16.51 
3.27 
5.19 
3.41 
6.69 
2.65 
2.93 
.20 
.95 
.53 
.30 
.18 
.06 
.10 
trace 
100. 23 
