CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
167 
2. ROCKS FROM THE HENRY MOUNTAINS. 
A. Porphyry. 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. Augi te-porphy rite, dike, north spur of Mount Pennell. Contains 
hornblende, augite, and plagioclase in a feldspathic groundmass. 
C. Hornblende-porphyrite, Mount Hillers. Contains plagioclase, 
hornblende, quartz, and magnetite. 
Analyses B and C by W. F. Hillebrand, record No. 1428. Rocks 
described by Cross in 11th Ann., p. 165. 
Si0 2 
ALA 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 100 c 
H 2 
Ti0 2 
PA 
MnO 
SrO. 
BaO. 
Li 2 
C0 2 . 
SO, . 
63.16 
17. 21 
2.43 
2.30 
1.27 
6.27 
4.70 
1.84 
.69 
.21 
.12 
trace 
trace? 
.09 
trace 
trace 
100. 29 
B. 
60.98 
19.09 
1.76 
1.15 
.65 
3.67 
6.70 
3.53 
.48 
.44 
.36 
.10 
.15 
.28 
.43 
trace 
.52 
100. 29 
62.88 
17. 13 
1.86 
2.58 
1.48 
5. 39 
4.50 
2.25 
.16 
.42 
.51 
.26 
.16 
.12 
.16 
trace 
99. 86 
