CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
145 
6. CASTLE MOUNTAIN DISTRICT. 
Rocks described by Weed and Pirsson in Bull. 139. Analyses made 
by Pirsson in the laboratory of the Sheffield Scientific School. 
A. Rhyolite, between Fourmile and Fivemile creeks, near Smith 
River. Liparose. Contains quartz, soda orthoclase, tourmaline, and 
a little iron ore and zircon. P. R. C. 560. 
B. Quartz-tourmaline-porphyry, upper Fourmile Creek. Liparose. 
Contains quartz, orthoclase, plagioclase, tourmaline, fluorite, and a 
little white mica, apatite, and zircon. P. R. C. 558. 
C. Granite, Elk Peak. Liparose. Contains quartz, orthoclase, 
oligoclase, biotite, hornblende, iron ore, apatite, sphene, and zircon. 
The last three minerals are rare. P. R. C. 551. 
D. Quartz-porphyry, sheet or ridge between Fourmile and Checker- 
board creeks. Liparose. Contains quartz, plagioclase, an untwinned 
feldspar and biotite, with occasional grains of iron ore and crystals of 
apatite and zircon. P. R. C. 557. 
E. Rhyolite-pitchstone, forks of Checkerboard Creek. Kallervd- 
ose. Essentially glass, inclosing grains of iron ore. P. R. C. 561. 
F. Aplitic granite, dike between Blackhawk and Robinson. Lipar- 
ose. Contains quartz and unstriated feldspar, some plagioclase, and 
occasional biotite. P. R. C. 553. 
G. Quartz-porphyry, Musselshell Canyon. Liparose. Contains 
quartz, biotite, plagioclase, apatite, iron ore, and zircon. P. R. C. 
556. 
Si0 2 .. 
ALA- 
Fe 2 3 . 
FeO.. 
MgO . 
CaO.. 
Na 2 0. 
H 2 0.. 
Ti0 2 . 
MnO. 
Li 2 . 
Sp.gr 
A. 
74.90 
13.64 
.66 
.50 
trace 
.61 
4.22 
4.64 
.33 
.15 
trace 
trace 
99. 65 
2.61 
B. 
74.82 
13.80 
.37 
.30 
.10 
.17 
4. 33 
4.81 
.83 
.25 
trace 
trace 
99.78 
2.59 
72.48 
13.14 
1.66 
1.02 
.15 
1.04 
4. 22 
4.88 
.42 
.32 
trace 
trace 
99.33 
2.62 
I). 
72.38 
14.71 
1.09 
.82 
.70 
.67 
4.28 
4.15 
.92 
.10 
trace 
trace 
99.82 
2.61 
E. 
72. 56 
12.33 
.80 
.82 
trace 
trace 
5.36 
3.08 
4.59 
.20 
trace 
99.74 
2.37 
72.88 
12.90 
.74 
1.05 
.75 
.81 
3.72 
5.03 
1.22 
.45 
.05 
71.67 
15.82 
1.18 
.35 
.13 
.25 
4.46 
4.45 
1.21 
.10 
trace 
)9.60 
2.64 
99. 62 
2.60 
Bull. 228—04 10 
