228 
ANALYSES OB' ROCKS, U. S. GEOLOGICAL SURVEY. 
[no. 228. 
G. Wall rock, Federal Loan mine. A siliceous argillite, of sedimen- 
tary origin. Contains quartz, feldspar, biotite, p3 T rrhotite, and a little 
calcite. Analysis by Hillebrand, No. 1478. 
H. Altered wall rock, Providence mine. Derived from granodio- 
rite. Analysis by Hillebrand, No. 1478. 
I. Altered wall rock, Providence mine, back vein. Derived from 
granodiorite and schist. Analysis by Hillebrand, No. 1478. 
J. Altered wall rock, North Star mine. Derived from uralite-dia- 
base. Contains quartz, sericite, calcite, pyrite, and sphene. Analysis 
by Hillebrand, No. 1478. 
K. Altered country rock, Idaho mine. Derived from serpentine. 
Analysis by Hillebrand, No. 1478. 
Si0 2 
A1A 
Fe,0 3 
FeO 
MgO 
CaO 
Na 2 ( ) 
K 2 
H 2 OatllO°... 
H 2 above 110' 
Ti0 2 . 
PA 
MnO 
MO 
SrO 
BaO 
Li 2 
co 2 
FeS 2 
Fe 7 S 8 
Organic C 
73.63 
10.54 
1.87 
1.S4 
2.47 
1.81 
1.89 
.11 
1.07 
.52 
.13 
trace? 
trace 
.12 
trace 
.62 
3.16 
.59 
100. 37 
ii. 
60. 26 
15. 73 
1.25 
2.68 
1.82 
5. 44 
1.92 
3.71 
.33 
2.54 
.42 
.12 
.04 
trace 1 
.07 
trace 
3.99 
.08 
100. 40 
59. 76 
14.45 
1.04 
3.52 
2. 26 
6.09 
1.12 
3.73 
.26 
2.58 
.46 
.16 
.09 
trace? 
.05 
trace 
4.47 
.24 
100. 28 
45. 74 
5.29 
.13 
2.06 
.94 
23.85 
.11 
1.29 
.22 
1.07 
.36 
.07 
.26 
none 
trace 
trace 
18.91 
.49 
100. 79 
36. 19 
4.93 
.•21 
5.36 
22.94 
4.60 
.16 
.06 
.IS 
2.87 
.16 
.05 
.12 
.10 
trace 
trace 
trace 
21.82 
.22 
99.97 
