CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
133 
The six following analyses represent alterations of quartz-monzonite, 
the so-called Butte granite: 
G. Weathered Butte granite. 
H. Altered Butte granite. Decomposed near quartz-pyrite veins. 
Shows opaline silica, with sericite derived from feldspar. Hornblende 
gone; mica recognizable only as sericite masses having the form of 
biotite. 
Analyses G and H by Stokes, record Nos. 1792, 17S7. 
I. Altered Butte granite, 300-foot level, Colusa mine. Derived 
from A. Contains quartz, altered orthoclase and plagioclase, and 
sericite. 
J. Altered Butte granite, wall rock, 1,300-foot level, Parrot mine. 
Derived from A. Contains quartz, sericite, pyrite, bornite, etc. 
K. Altered Butte granite, enargite vein, 1,000-foot level, Leonard 
mine. Contains quartz, kaolin, pyrite, etc. 
L. Altered Butte granite, veinlets in Original mine. Contains 
quartz, sericite, partly altered feldspars, calcite, zinc blende, etc. 
Analyses I, J, by E. T. Allen, record No. 1961; K, L, by W. F. 
Hillebrand, record No. 1971. 
Si0 2 .. 
ALA- 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 0at 110°.... 
H 2 above 110° 
Ti0 2 
CO, 
S 
so 3 
FeS 2 
Cr 2 3 
MnO 
SrO 
BaO 
Li 2 
ZnO 
Fe, total iron 
Cu 
<) 
65. 14 
15. 63 
2.37 
2.13 
1.85 
3.62 
2.63 
4.29 
.37 
.75 
.59 
none 
.16 
05 
trace 
trace 
.10 
trace 
99. 68 
II. 
64.81 
19.44 
1.82 
.16 
.19 
.18 
.21 
5.30 
1.41 
5.25 
.73 
none 
.10 
.31 
trace 
trace 
.10 
trace 
100. 01 
56. 80 
21.02 
3.06 
.90 
1.21 
.35 
.50 
4.78 
2. 88 
7.68 
.60 
none 
.05 
.17 
none 
trace 
trace 
05 
K) 
100. 15 
.06 
100.09 
.1. 
62.09 
15.49 
8.52 
.42 
.20 
.37 
4.34 
1.20 
3.01 
.51 
none 
.13 
5.47 
none 
none 
trace? 
trace 
25 
102. 00 
2.05 
99. 95 
K. 
66. 90 
15. 83 
(?) 
(?) 
trace 
.05 
.08 
.03 
.87 
3.88 
.68 
none 
5.46 
none 
4.37 
present 
98. 15 
L. 
54.30 
13.63 
1.-89 
2.22 
2.13 
7.36 
.16 
4.41 
2.19 
4.09 
.61 
5.50 
.20 
none 
.49 
.71 
trace 
.12 
100.01 
