142 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
B. Granite-porphyry, Wolf Butte. Toscanose. Phenocrysts of 
quartz, orthoclase, plagioclase, and biotite in a groundmass of quartz 
and alkali feldspar. A little apatite and iron ore, with secondary 
calcite, limonite, chlorite, and white mica. Analysis by Stokes. 
C. Granite-porphyry, top of Barker Mountain. Toscanose. Pheno- 
crysts of orthoclase, oligoclase, biotite, green hornblende, sphene, and 
iron ore, in a groundmass of quartz and alkali feldspar. Also a little 
apatite and some secondary chlorite and limonite. Analysis by Stokes. 
D. Syenite, Wright and Edwards mine, Hughesville, near Barker. 
Toscanose. Very fresh rock. Contains magnetite, ilmenite, horn- 
blende, anorthoclase, albite, subordinate quartz, a little chlorite, cal- 
cite, and limonite, and white mica in traces. Analysis by Stokes. 
E. Syenite, Yogo Peak. Monzonose. Described in Amer. Journ. Sci. , 
3d series, vol. 50, p. 171. Contains apatite, sphene, iron ore, p3^roxene, 
hornblende, biotite, orthoclase, oligoclase, and quartz, with traces of 
chlorite and limonite and a little kaolin. Analysis by Hillebrand. 
F. Syenite-porphyry, dike at head of Sheep Creek. Toscanose. 
Phenocrysts of orthoclase, some plagioclase, and green hornblende, 
in a groundmass of alkali feldspar, with some quartz. Also contains 
a little apatite and iron ore, with some secondary calcite and kaolin. 
Analysis by Hillebrand. 
Si0 2 .. 
A1A- 
Fe 2 3 
FeO.. 
MgO. 
CaO.. 
Na 2 0. 
K 2 0.. 
H 2 above 110° 
Ti0 2 
PA 
OA 
MnO 
SrO.. 
BaO 
Li 2 
co 2 
so 3 
CI 
73.12 
14.27 
.51 
.26 
.24 
1.10 
3.43 
4.90 
.68 
.73 
.08 
.03 
none 
.06 
trace 
trace 
trace 
.77 
100. 18 
15. 
69.68 
14.97 
.79 
.34 
.66 
2.10 
3.38 
4.40 
1.09 
.92 
.28 
.17 
trace 
.06 
.14 
trace 
.88 
trace 
trace 
99.86 
68.60 
16. 13 
2.22 
.44 
.72 
1.36 
4.37 
4.89 
.20 
.58 
.32 
.18 
trace 
.09 
.27 
trace 
trace 
trace 
100. 37 
i>. 
64.64 
16. 27 
2.42 
1.58 
1.27 
2. 65 
4.39 
4.98 
.09 
.27 
.51 
.37 
trace 
.08 
.18 
.37 
trace 
.05 
100. 12 
E. 
61.65 
15. 07 
2.03 
2.25 
3.67 
4.61 
4.35 
4.50 
.26 
.41 
.56 
.33 
trace 
.09 
.10 
.27 
trace 
100. 15 
66. 29 
15.09 
1.37 
1.17 
2.39 
2.38 
3.96 
4.91 
.39 
.60 
.27 
.15 
none 
.06 
.07 
.30 
trace 
.45 
99.85 
