144 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
M. Minette, intrusive sheet, head of Sheep Creek. Monzonose. 
Chiefly biotite, augite, and orthoclase, with accessory apatite, plagio- 
clase, quartz, and iron ore, and some secondary calcite, chlorite, and 
kaolin. Analysis by Hillebrand. 
N. Monzonite, Yogo Peak. Monzonoxe. Described in Amer. Journ. 
Sci., 3d series, vol. 50, p. 473, and 4th series, vol. 1, p. 356. Contains 
apatite, sphene, iron ore, pyroxene, hornblende, biotite, orthoclase, 
and oligoclase, and a little secondary kaolin. Analysis by Hillebrand. 
O. Monchiquite, dike on Big Baldy Mountain. Monchlquose. Con- 
tains much pyroxene, a few serpentinized olivines, iron ore, and apatite 
in a colorless base of analcite. Analysis by Hillebrand. 
P. Monchiquite, dike on Bandbox Mountain. Near Wyoming ose. 
Contains olivine, augite, biotite, analcite, and apatite, with traces of 
serpentine and chlorite. Analysis by Stokes. 
Q. Shonkinite, Yogo Peak. Shonkinose. Described in Amer. Journ. 
Sci., 3d series, vol. 50, p. 474. Chiefly augite and orthoclase, with a 
considerable amount of accessory biotite, iron ore, and andesine, less 
apatite and olivine, and a trace of kaolin. Analysis by Hillebrand. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oat 110°... 
H 2 above 11 C 
Ti0 2 
PA 
CrA--- 
NiO 
MnO 
SrO 
BaO. 
S0 3 
CI.. 
co 2 
F . 
52.26 
13.96 
2.76 
4.45 
8.21 
7.06 
2.80 
3.87 
1.53 
1.34 
.58 
.52 
trace 
.14 
.05 
.23 
trace 
.49 
100. 25 
54.42 
14.28 
3.32 
4.13 
6.12 
7.72 
3.44 
4.22 
.22 
.38 
.80 
.59 
trace 
.10 
.13 
.32 
trace 
100. 19 
48. 35 
13.27 
4.38 
3.23 
8.36 
9.94 
3.35 
3.01 
.90 
2. 89 
.52 
.40 
trace 
.04 
.19 
.09 
.54 
trace 
.30 
.25 
100. 01 
r. 
48.39 
11.64 
4.09 
3.57 
12.55 
7.64 
4.14 
3.24 
.28 
2.56 
.73 
.45 
.07 
trace 
.15 
.32 
trace 
.08 
trace 
99. 90 
Q. 
48.98 
12.29 
2.88 
5.77 
9.19 
9.65 
2.22 
4.96 
.26 
.56 
1.44 
.98 
trace 
.08 
.08 
.43 
trace 
.22 
99. 99 
