196 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[BULL. 168. 
L. Bleached country rock, next to vein, Osborne Hill mine. Derived 
from sandstone. Analysis by George Steiger, record No. 1541. 
M. Altered wall rock, Empire mine. Derived from granodiorite. 
Analysis by Steiger, No. 1541. Sp. gr., 2.782, 20°. 
N. Altered wall rock, Ebaugh tunnel. Derived from granodiorite. 
Mainly quartz and sericite, with pyrite, apatite, sphene, and carbonates. 
Analysis by Steiger, No. 1541. Sp. gr., 2.747, 20°. 
O. Altered wall rock, Federal Loan mine. Derived from siliceous 
argillite. Analysis by Steiger, No. 1541. 
Si0 2 
ALA 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl00°... 
H 2 above 100 
Ti0 2 
PA 
MnO 
BaO 
so 3 
co 2 
FeS 2 
L. 
71.97 
15. 75 
.77 
.45 
.80 
.80 
.33 
4.88 
.30 
2.16 
.88 
.15 
none 
trace 
trace 
.38 
.56 
100. 18 
M. 
58.43 
17.40 
.77 
2.19 
1.50 
5.25 
1.76 
4.03 
.30 
2.61 
none 
.13 
none 
none 
none 
4.04 
1.59 
100. 00 
56. 25 
17.65 
.76 
2.64 
1.69 
4.46 
.30 
6.01 
.30 
2.36 
.25 
.21 
none 
.03 
none 
4.82 
2.87 
100. 60 
34.91 
15. 55 
.17 
4.96 
4.58 
11.10 
.19 
4.28 
.30 
1.86 
1.65 
.82 
none 
none 
none 
15.57 
4.20 
100. 14 
