202 
ANALYSES OF EOCKS, U. S. GEOLOGICAL SURVEY. 
[no. 228. 
F. Typical hypersthene-andesite, San Francisco Mountains. Lassen- 
ose. Not described. Analysis by T. M. Chatard, record No. 270. 
G. Recent lava, 2 miles south of Mount Trumbull. Camptonose. 
Not described. Analysis by L. G. Eakins, record No. 1024. 
H. Tourmaline hearing alkali-granite, 5 miles northwest of Bisbee. 
Ziparose. Contains microperthitic orthoclase, quartz, oligoclase, 
biotite, tourmaline, muscovite, apatite, zircon, and iron ore. P. R. C. 
1395. 
I. Granite-porphyry, 3i miles north of Waco Junction, Bisbee 
quadrangle. SB. 1 of alaskase. Contains quartz, orthoclase, oligo- 
clase, biotite, muscovite, zircon, and iron ore. P. R. C. 1396. 
Rocks II and I are described by F. L. Ransome in P. P. 21. 
Analyses by George Steiger, record No. 2031. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
Mg( ) 
CaO 
Na 2 
K,0 
H 2 Oat 105°.... 
H,0 above 105° 
Ti0 2 
PA ---.. 
MnO 
82 
27 
48 
56 
85 
89 
05 
<;: 
I'D 
99.78 
15.30 
14.95 
1 . 98 
9.32 
8.29 
8.87 
4.27 
1.27 
.85 
56 
2. 66 
23 
2.23 
20 
trace 
99. 99 
75. 86 
12.17 
. 85 
. 36 
none 
.62 
3.60 
5. 04 
.27 
.72 
.21 
trace 
none 
99.70 
76. 81 
10. 96 
1.18 
.08 
.14 
none 
.26 
8.50 
.48 
1.17 
.13 
trace 
none 
99. 71 
NEVADA. 
1. TONOPAH DISTRICT. 
Rocks A to F, inclusive, represent hornblende-andesite and its 
various alterations. Collected by J. E. Spun*, hitherto unpublished. 
Analyses by George Steiger, record No. 2067. 
A. Hornblende-andesite, California-Ton opah shaft. Pantellerose. 
The freshest obtainable. Contains andesine, pseudomorphs of chlorite 
after hornblende, some quartz, pyrite, and apatite. 
B. Hornblende-andesite, also relatively fresh. No. 2 shaft. Kal- 
lerudose near pantellerose. Contains partly altered, striated feldspars, 
and pseudomorphs of quartz, pyrite, etc., after biotite and hornblende. 
The rock is partly altered to quartz and muscovite. 
