CLARK E.J 
IGNEOUS AMD CRYSTALLINE ROCKS. 
153 
4:. BUFFALO PEAKS. 
Hypersthene-andesite, described by Cross in Bull. 1. Contains hy- 
persthene, augite, plagioclase, magnetite, and apatite. Sp. gr. 2.742, 
16°. Analyses made by W. F. Hillebrand in the Denver laboratory. 
A. Hypersthene-andesite. P. R. C. 588. 
B, C, D. Hypersthene separated from the rock. Sp. gr. of D, 
3.307, 23°. In B and C alkalies were not tested for. In C and D all 
the iron is given as FeO. 
A. 
B. 
c. 
I). 
Si0 2 
56.19 
16.12 
4.92 
4.43 
4.60 
7.00 
2.96 
2.37 
1.03 
.27 
trace 
trace 
trace 
.02 
51. 70 
1.72 
.30 
18.00 
25.09 
2.87 
51.16 
2.15 
50.04 
2.91 
ALO, 
Fe.,Oo 
FeO 
18. 36 
24. 25 
3.81 
17. 81 
21.74 
6.70 
.27 
MgO 
CaO 
Na 2 
K 2 
H 2 0.. 
P 9 (X 
MnO 
.36 
.36 
.12 
SrO 
BaO.i 
CI 
99.91 
100. 04 
100. 10 
99.59 
