CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
143 
G. Syenite-porphyry, intrusive sheet, between Yogo Peak and Big 
Baldy Mountain. Lassenose. Abundant phenocrysts of hornblende 
and orthoclase, with less biotite and plagioclase, in a groundmass of 
alkali feldspar with accessory quartz. Also contains iron ore and 
apatite, with secondary calcite, chlorite, sericite, and kaolin. Analysis 
by Hillebrand. 
H. Granite-syenite-porphyry, north end of Thunder Mountain. 
Woscanose. Phenocrysts of orthoclase, oligoclase, hornblende, and 
biotite, in a groundmass of alkali feldspar and very abundant quartz. 
Also contains a little sphene, iron ore, and apatite, very little second- 
ary chlorite and limonite, and a trace of kaolin. Analysis by Stokes. 
I. Quartz-syenite-porphyry, top of Big Baldy Mountain. Toscanose. 
Phenocrysts of orthoclase, plagioclase, biotite, iron ore, brown horn- 
blende, and sphene, in a groundmass of quartz and alkali feldspar. 
Also contains a little apatite, with traces of chlorite, limonite, and 
kaolin. Analysis by Hillebrand. 
J. Syenite-diorite-porphyry, talus slope on west side of Bear Park. 
W)acose. Phenocrysts of biotite, hornblende, plagioclase, and ortho- 
clase, in a groundmass of quartz and alkali feldspar. Also contains a 
little magnetite, chlorite, white mica, and apatite. Analysis by Stokes. 
K. Diorite-porphyry, Steamboat Mountain. Adamellose. Pheno- 
crysts of orthoclase, plagioclase, hornblende, and biotite, with a little 
iron ore and apatite, in a groundmass of orthoclase, plagioclase, and 
quartz. Analysis by Stokes. 
L. Diorite, Carpenter Creek, near Neihart. Andose. Contains 
green hornblende, biotite, and plagioclase, with some apatite, iron 
ore, calcite, kaolin, and muscovite, and a very little quartz and 
orthoclase. Analysis by Hillebrand. 
G. 
H. 
I. 
J. 
K. 
L. 
Si0 2 
62.58 
16.42 
2.46 
1.96 
1.84 
2.47 
4.57 
3.91 
.38 
1.40 
.40 
.33 
.08 
.10 
.41 
trace 
. 77 
67.44 
15.78 
1.58 
.85 
1.43 
2.38 
4.11 
4.87 
.32 
.70 
.32 
.21 
trace 
.09 
.24 
trace 
67.04 
15.25 
1.69 
1.13 
1.75 
2.17 
4.09 
5.10 
.56 
.51 
.20 
.21 
.05 
.03 
.33 
trace? 
64.95 
15.44 
2.02 
1.60 
2.65 
3.07 
4.25 
3.87 
.26 
.85 
.39 
.25 
trace 
.10 
.35 
62.18 
15.77 
1.83 
2.44 
3.55 
4.13 
3.92 
3.91 
.30 
.70 
.55 
.32 
trace 
.16 
.43 
trace 
55.13 
ALO, 
20 27 
Fe 2 0, 
1.52 
FeO 
4.29 
MgO 
1.80 
CaO 
7.05 
Na 2 
K 2 () 
4.31 
2.84 
1.0 at 110° 
.14 
H 2 above 110° 
.95 
Ti0 2 
.74 
P 2 () 5 
.40 
MnO 
.13 
SrO 
.06 
BaO 
.11 
Li 2 
trace 
C0 2 
.26 
so 3 
trace 
trace 
.02 
.04 
trace 
.04 
CI. 
100. OS 
100. 32 
100. 11 
100.11 
100. 23 
100. 00 
