96 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[bull. 168. 
3d. ishawooa intrusives. 
Descriptions, hitherto unpublished, supplied by Arnold Hague and 
T, A. Jaggar, jr. Analyses A and B by H. N. Stokes, record No. 1804; 
C and D by W. F. Hillebrand, No. 1765. 
A. Granite-porphyry, base of Crater Mountain. Contains oligo- 
clase, orthoclase, biotite, and quartz. 
B. Diorite-porphyry, Cabin Creek. Contains plagioclase, ortho- 
clase, quartz, and abundant hornblende. This rock is intermediate 
between granite-porphyry and diorite-porphyry, but nearer to the 
latter. 
C. Diorite, base of Needle Mountain. Contains plagioclase, quartz, 
biotite, with subordinate hornblende and orthoclase. Structure 
granitic. 
D. Diabase, entrance to Shoshone Canyon. Contains plagioclase, 
augite, and chlorite. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 110°... 
H 2 above 110 c 
Ti0 2 
PA 
MO 
MnO 
SrO 
BaO 
Li 2 
C0 2 
CI 
s 
FeS 9 
64.23 
16.34 
1.07 
1.58 
2.47 
3.07 
3.49 
2.59 
.47 
1.76 
.50 
.18 
none 
trace 
.06 
.19 
trace 
.30 
1.61 
99.91 
60.00 
16.37 
2.28 
2.46 
3.81 
4.96 
3.73 
2.70 
.61 
1.42 
.59 
.35 
none 
.05 
.11 
.26 
trace 
.17 
99.87 
63.76 
16.01 
2.22 
1.96 
2.43 
4.55 
3.98 
2.84 
.28 
.57 
.52 
.25 
none 
.09 
.09 
.17 
trace 
.23 
trace 
(?) 
99. 95 
52.18 
18.19 
3.31 
4.36 
4.69 
6.51 
4.58 
1.88 
.75 
2.00 
.99 
.29 
trace 
.14 
.06 
.11 
trace 
none 
trace 
none 
100. 04 
