CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
139 
I. Quartz-monzonite, Schafer Butte, Boise County. Contains 
quartz, orthoclase, oligoclase, biotite, apatite, titanite, and magnetite. 
To be described in 20th Ann. Analysis by George Steiger, record 
No. 1802. 
J. Granodiorite, Silver Wreath mine, Boise County. Contains 
orthoclase, oligoclase, apatite, biotite, titanite, and magnetite. De- 
scribed in 18th Ann., Part III, p. 642. Sp. gr. 2.714, 23°. 
K. Same as J, but in altered condition. Also described in 18th Ann. 
Contains sericite, quartz, titanite, apatite, and pyrite, with carbonates 
of calcium, magnesium, and iron. Sp. gr. 2.774, 23°. 
Analyses J and K by George Steiger, record No. 1691. 
Si0 2 .. 
ALA. 
Fe 2 3 
FeO.-. 
MgO . 
CaO.. 
Na 2 0. 
KjO.. 
H 2 above 100° 
Ti0 2 
P 2 5 
MnO 
BaO... 
S 
co 2 
Less 0=S 
69.56 
15.29 
.86 
2.06 
.69 
2.81 
3.97 
3.36 
.86 
.55 
.16 
100. 17 
65. 23 
16.94 
1.60 
1.91 
1.31 
3.85 
3.57 
3.02 
.18 
.88 
.66 
.19 
trace 
.19 
none 
.25 
99.78 
66.66 
14.26 
.67 
2.41 
.95 
3.37 
none 
4.19 
.36 
2.16 
.49 
.17 
trace 
none 
.95 
3.67 
100. 31 
.24 
100.07 
