176 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
CALIFORNIA. 
1. MOUNT SHASTA. 
Description of rocks furnished by J. S. Diller, who also describes 
A, B, and C in Bull. 150, pp. 221, 227. 
A. Hornblende-andesite, Black Butte, west base of Shasta. Con- 
tains plagioclase and hornblende in a microlitic groundinass. The lat- 
ter carries hypersthene, magnetite, and amorphous matter. Analysis 
by W. H. Melville, record No. 1346. P. R. C. 84. 
B. Hypersthene-andesite, older flow, west base of Shasta. Contains 
plagioclase, hypersthene, magnetite, and glass. Analysis by Melville, 
No. 1346. 
C. Hypersthene-»andesite, like B, same locality, later flow. Analysis 
by Melville, No. 1346. P. R. C. 87. 
D. Hornblende-andesite, late flow, eastern side of Shasta. Contains 
small crystals of plagioclase and hornblende in a dark groundmass. 
Thin section not examined. Analysis by H. N. Stokes, record No. 1532. 
E. Ophitic basalt from near the McCloud River, south of Mount 
Shasta. A gray cellular rock. Thin section not examined. Analysis 
by Stokes, No. 1532. 
F. Andesite basalt, Delta, Shasta County. Much plagioclase and a 
few hypersthene crystals in a groundmass chiefly of feldspar, pyroxene, 
magnetite, and trace of olivine. Analysis by Melville, No. 1346. 
A. 
B. 
c. 
D. 
E. 
F. 
Si 2 
A1 2 3 
64.48 
19.28 
1.40 
1.78 
1.64 
5.06 
4.41 
1.12 
\ .06 
undet. 
64.52 
18. 31 
.90 
2.51 
2.35 
5.11 
4.64 
1.25 
\ .20 
undet. 
63. 03 
17.72 
2.27 
1.92 
3. 63 
5.97 
3.92 
1.06 
\ .44 
undet. 
61. 58 
16. 96 
1.75 
2.85 
3.67 
6.28 
3.94 
1.28 
.24 
1.06 
.49 
.22 
trace 
trace 
.03 
trace 
47.94 
18.90 
2.21 
8.59 
8.21 
9.86 
2.81 
.29 
.39 
.74 
.57 
.15 
h-ace 
none 
none 
trace 
55. 08 
18.93 
2.02 
5.56 
5.17 
8.40 
4.23 
.74 
| .29 
trace 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oat 110°... 
H 2 above 110° 
Ti0 2 
P 2 5 
MnO 
SrO 
BaO 
Li 2 
99.23 
99.79 
99.96 
100. 35 
100. 66 
100. 42 
