86 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
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 Checkerboard 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. Kallerudose. Essentially 
glass, inclosing grains of iron ore. P.R.C. 561. 
F. Aplitic granite, dike between Blackhawk and Robinson. Liparose. 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. 
37 1. 66 1.09 80 74 ‘ 
30 1. 02 - 82 82 1.05 - 35 
10 15 .70 | trace 75 -13 
17 1.04 . 67 trace 81 ~25 
4.33 4.22 4.28 5. 36 3.72 4. 46 
4,81 4.88 4.15 3.08 5.03 4. 45, 
83 42 - 92 4.59 1,22 1 
trace | trace | trace | trace 05 trace 
H. Feldspar porphyry, dike below Castle. Zassenose. Contains orthoclase, less 
plagioclase, hornblende, biotite partly altered to chlorite, sometimes allanite, and 
occasional iron ore, apatite, and zircon. P.R.C. 5565. 
I. Rhyolitic tuff, near forks of Checkerboard Creek. Contains fragments of shale, 
quartz, plagioclase, sanidine, and hornblende, in a brownish material carrying pumi- 
ceous glass. Much decomposed, with formation of kaolin. P.R. C. 562. 
J. Syenitic mass included in granite, head of Cottonwood Creek. Akerose. Con- 
tains orthoclase, plagioclase, quartz, hornblende, biotite, apatite, and iron ore. A 
hornblende-mica syenite. P. R. C. 554. 
K. Diorite, between Blackhawk and Robinson. Andose. Contains plagioclase, 
orthoclase, quartz, biotite, diallage, hypersthene, iron ore, apatite, and zircon. P. R.C 
509. 
L. Basalt, Volcano Butte. Kilauose. Contains labradorite, augite, olivine, a little 
serpentine, occasional quartz grains, small patches of glass, iron ore, chiefly ilmenite, 
apatite, a trace of calcite, and a mineral which may be nephelite or analcite, P,R.C. 
565, 
