142 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[BULL. 
C. Porphyritic granitite, south side of Pikes Peak, ridge between 
Middle and North Beaver creeks. Contains microcline, perthite, 
orthoclase, oligoclase, quartz, biotite, and accessory apatite, fluorite, 
zircon, and magnetite. P. R. C. 602. 
D. Sheared granite, Currant Creek Canyon, north of Twelvemile 
Park. Contains perthitic microcline, quartz, muscovite, and sericitic 
aggregates replacing plagioclase and a part of the microcline. P. R. C. 
604. 
E. Granite, Currant Creek Canyon, north of Twelvemile Park. 
Consists chiefly of perthitic microcline, quartz, greenish biotite, mus- 
covite, and plagioclase altered to a sericitic mass. Also flakes of 
limonite. Accessory minerals rare. P. R. C. 603. 
F. Granitite, Middle Beaver Creek, south side of Pikes Peak. Con- 
tains microcline, orthoclase, perthitic albite, oligoclase, abundant 
quartz, biotite, and a little accessory magnetite, fluorite, and zircon. 
P. R. C. 601. 
G. Granite-gneiss, north of Twin Creek. Contains microcline, 
orthoclase, quartz, biotite, abundant fluorite, and a little sphene and 
apatite. P. R. C. 605. 
SiO,.. 
A1 2 3 - 
Fe 2 3 
FeO.. 
MgO . 
CaO.. 
K 2 
H 9 at 110 c 
Ti0 2 
PA 
MnO 
SrO. 
BaO. 
Li 2 
F... 
C0 2 . 
Less O . 
A. 
77.03 
12.00 
.76 
.86 
.04 
.80 
3.21 
4.92 
.14 
.30 
.13 
trace 
trace 
none 
trace 
trace 
.36 
100. 55 
.15 
100. 40 
B. 
75. 92 
12.96 
.33 
1.40 
trace 
.15 
4.60 
4.15 
.16 
.32 
.05 
trace 
.04 
none 
trace 
trace 
.12 
.03 
100. 23 
.05 
100. 18 
75.17 
12.66 
.23 
1.40 
.05 
.82 
2.88 
5.75 
.16 
.66 
.10 
.03 
trace 
trace ? 
.03 
trace 
.31 
100. 26 
.13 
100. 13 
74.40 
14.43 
.89 
.22 
.07 
.58 
1.76 
6.56 
.15 
.92 
.12 
.22 
trace 
none 
trace 
trace 
.04 
100. 36 
.02 
100. 34 
73.90 
13.65 
.28 
.42 
.14 
.23 
2.53 
7.99 
.16 
.33 
.07 
.05 
trace 
none 
trace 
trace 
none 
99.75 
73.51 
13.28 
.94 
.97 
.05 
1.11 
3.79 
5.22 
.16 
.62 
.18 
trace 
trace 
none 
trace 
trace 
.55 
100. 38 
.22 
100.16 
66.90 
14.86 
.93 
3.41 
.31 
1.23 
5.56 
5.02 
.16 
.31 
.43 
.12 
.15 
none 
.14 
.06 
1.00 
100. 59 
.42 
100.17 
