lV)i) 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[no. 228. 
3. ROCKS FROM BINGHAM. 
Porphyries collected by J. M. Boutwell, but not yet described. 
Analyses by E. T. Allen, record No. 1985. 
A. From Tribune tunnel, Telegraph mine. Manzonose. 
B, C, D. From British tunnel, Last Chance mine. B, SR. 1 of 
olacase. C, harzose. D, monzonose. 
According- to Boutwell, A is the characteristic Bingham porphyry, 
and is intermediate between diorite-porphyry and monzonite. It con- 
tains chiefly augite, biotite, and plagioclase, with a few grains of 
pyrite. B, C, and 1) are altered forms of this rock. 
Si0 2 
A1 2 3 
Fe 2 3 ---- 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oat_105°.... 
H 2 above 105° 
Ti0 2 
CO, 
PA 
s 
Cr 2 3 
MnO 
BaO 
Less ( >=S 
A. 
57.16 
16. 69 
3.47 
2. 76 
2.47 
5.86 
3.82 
4. 49 
.83 
1.06 
.87 
none 
.41 
.02 
trace 
trace 
.30 
100. 21 
.01 
100. 20 
56.78 
16.90 
6.87 
2.34 
.03 
1. is 
.37 
7.02 
1.32 
2.23 
.81 
.26 
.04 
5. 93 
trace 
trace 
.11 
102. 22 
2.22 
100. 00 
56.17 
15.94 
3.43 
1.92 
1.60 
5.19 
2.48 
4.91 
1.30 
2.95 
.90 
2.01 
.20 
1.03 
trace 
.18 
100. 21 
.39 
99.82 
D. 
58.64 
15.35 
3.25 
2. 54 
3.84 
5.37 
3.60 
4.23 
.86 
1.50 
.83 
none 
.02 
.05 
trace 
trace 
.18 
100. 26 
.02 
100. 24 
4. ROCKS FROM THE LA SAL MOUNTAINS. 
Hitherto unpublished data. Petrographic descriptions by L. M. 
Prindle. Analyses by W. F. Hillebrand, record No. 2032. 
A. Monzonite porphyry, 2 miles west of Mount Peale. Akerose. 
Contains phenocrysts of plagioclase, partly resorbed hornblende, and 
pyroxene in a groundmass of partly striated feldspar. It may contain 
also orthoclase and quartz. P. R. C. 1306. 
B. Aegirite-granite porphyry, about 1.5 miles south of Mount Waas. 
Omeose-liparose. Contains quartz, feldspar, pyroxene, and iron ore. 
The pyroxene is probably for the most part aegirite. P. R. C. 1304 
