CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
189 
2. ROCKS FROM HENRY MOUNTAINS. 
A. Porphyry. Tonalose. Not hitherto published. Reported by 
J. S. Diller as containing prominent plagioclase with some augite and 
hornblende in a crystalline groundmass of quartz and orthoclase. 
Analysis by R. B. Riggs, record No. 728. 
B. Angite-porphyrite, dike, north spur of Mount Pennell. Laur- 
vikose. Contains hornblende, augite, and plagioclase in a feldspathic 
groundmass. 
C. Hornblende-porphyrite, Mount Hillers. Tonalose. Contains 
plagioclase, hornblende, quartz, and magnetite. 
Analyses B and C by W. F. Hillebrand, record No. 1128. Rocks 
described by Cross in 14th Ann., p. 165. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO.. 
MgO 
CaO 
Na.,0 
K/> 
Ii 2 ( ) at 100° . . . 
II 2 () above 100° 
Ti() 2 
P.O. 
r 
MnO 
SrO. 
BaO. 
LLO 
co 2 . 
so 3 . 
63. 16 
17.21 
2.43 
2.30 
1.27 
6.27 
4.70 
1.84 
.60 
.21 
.12 
trace 
trace ? 
.00 
trace 
trace 
100. 20 
60.08 
10.09 
1. 76 
1.15 
.65 
3.67 
6.70 
3. 53 
.48 
.44 
.36 
.10 
.15 
.28 
.43 
trace 
.52 
100. 20 
62.88 
17. 13 
l.si) 
2. 58 
1.48 
5.39 
4.50 
2.25 
.16 
.42 
.51 
.26 
.16 
.12 
.16 
t race, 
99.86 
