CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
233 
9. AMADOR COUNTY. 
Rocks collected by H. W. Turner, and analyses published in 14th 
Ann., p. 441, and 17th Ann., Part I, p. 521. Additional data supplied 
by Turner. Analyses by W. F. Hillebrand, record Nos. 1432, 1456, 
and 1597. 
A. Rhyolite, south point of Buena Vista Peak. Magdeburgose. 
Contains sanidine, quartz, and biotite in a glassy groundmass. 
P. R. C. 729. 
B. Quartz-inonzonite, north fork of Mokelumne River. Amiatose. 
Contains plagioclase, microcline, quartz, abundant biotite, iron ore, 
sphene, apatite, and perhaps rutile. P. R. C. 770. 
C. Quartz-nionzonite, north fork of the Mokelumne River. Toscan- 
ose. Like B. P. R. C. 765. 
D. Quartz-porplry rite-schist, 2| miles southeast of Buena Vista 
Peak. Tehamose. Contains porphyritic quartz and hornblende, also 
calcite and other carbonates. See 14th Ann. P. R. C. 723. 
E. Quartz-diorite-gneiss, north fork of Mokelumne River. Tonal- 
fse. Contains plagioclase, hornblende, quartz, brown mica, accessory 
biotite, and iron oxide. P. R. C. 764. 
F. Diorite-porphyry, north fork of Mokelumne River. Andose. 
Contains plagioclase, brown hornblende, epidote, and a little sulphide 
of iron and chlorite. P. R, C. 769. 
Ii0 2 
Al,() :! 
Fe 2 :i 
FeO 
MgO 
CaO 
Na,( ) 
K 2 
k 2 Oatl00°.... 
H 2 above 100° 
Ti0 2 
P.,(Y 
Ni( ) . 
MnO 
SrO . 
BaO. 
Li 2 (). 
bo 2 . 
FeS,. 
A. 
73. 23 
12.73 
.99 
.16 
. 22 
.61 
1.91 
5. 17 
.53 
4.51 
.09 
.02 
trace 
none 
.02 
trace 
100. 19 
B. 
70. 75 
15.13 
.98 
1.43 
.73 
3.09 
3.05 
3.62 
.10 
.51 
.42 
.10 
none 
trace 
.04 
.12 
trace 
none 
.06 
100. 13 
70. 43 
15. 51 
.96 
1.28 
.37 
2.76 
2.75 
5.14 
.08 
.40 
.24 
.11 
(?) 
trace 
.05 
.20 
trace 
none 
trace 
100. 28 
i>. 
70.29 
11. 83 
1. 30 
2.08 
1.24 
2.30 
2. 68 
3. 05 
.10 
1.35 
.29 
.07 
.12 
trace? 
.07 
none 
3.25 
100.02 
57. 41 
17.71 
2.16 
5.01 
3.38 
6.73 
3.12 
1.82 
.20 
1.14 
1.04 
.24 
.02 
.15 
.04 
.09 
trace 
none 
none 
100.26 
55. 18 
17. 35 
2.77 
3. 90 
4.80 
7.98 
3.42 
1.42 
.16 
1.52 
.83 
.20 
.03 
.15 
.06 
.04 
trace 
none 
.28 
100.09 
