110 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[NO. 228. 
L. Hornblende-mica-andesite-porphyry dike, ridge south of Hurri- 
cane Ridge. Tonalose. Contains plagioclase, hornblende, biotite, 
augite, hypersthene, and magnetite, with a little chlorite or serpen- 
tine. Analysis by Eakins, No. 1087. 
M. Quartz - diorite - porphyry, Hurricane Ridge. Yellowstonose. 
Contains plagioclase, orthoclase, quartz, augite, hypersthene, magnet- 
ite, and a little biotite. Analysis by Melville, No. 1234. 
N. Quartz-mica-diorite, Hurricane Ridge. Adamellose. Contains 
andesine, orthoclase, quartz, biotite, hornblende, magnetite, and a 
little pyroxene. Analysis by Melville, No. 1234. 
O. Quartz-mica-diorite-porphyry, Hurricane Ridge. Toscanose. 
Contains andesine, orthoclase, quartz, and biotite. Analysis by Mel- 
ville, No. 1231. 
P. Aplite dike, Hurricane Ridge. Toscanose. Contains quartz, 
orthoclase, oligoclase, biotite, magnetite, some chlorite, and a little 
hornblende. Analysis by Eakins, No. 1088. 
Si0 2 .. 
A1 2 3 . 
Fe 2 3 
FeO.. 
MgO . 
CaO.. 
K 2 
H 2 Oat 100°.... 
H 2 above 100° 
Ti0 2 
PA 
MnO 
NiO 
CI 
61.16 
16.17 
2.89 
2.18 
3.89 
4.26 
3.87 
3.20 
2.09 
.23 
.13 
trace 
100. 07 
M. 
63.42 
17.16 
3.09 
1.50 
1.64 
4.65 
4.51 
3.04 
.16 
.28 
.35 
.26 
.04 
.19 
100. 29 
N. 
63.97 
15.78 
2.35 
1.87 
2.84 
3.71 
4.36 
4.01 
.09 
.49 
.48 
.40 
.05 
trace 
100. 40 
100. 27 
71.62 
14.99 
1.27 
1.01 
.74 
1.33 
3.62 
4.81 
.41 
.08 
trace 
.17 
trace 
100. 05 
