86 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[no. 228. 
E. Feldspar separated from gabbro, southern half of sec. 14, T. 44 
N., R. 4 W., Wisconsin. 
F, G. Feldspars separated from olivine-diabase, NE. i of sec. 13, 
T. 45 N., R. 1 W., Wisconsin. P. R. C. 1003. 
Si0 2 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na. 2 ( ) 
K 2 
H 2 Oatl05°.. 
H 2 above 10 
MnO 
51.99 
29. 32 
1. 23 
.63 
12. 60 
2.91 
.28 
. 03 
.54 
trace 
99. 53 
61.65 
19.91 
2.28 
undet. 
.61 
4.12 
4.74 
5.72 
. 95 
trace 
G. 
56. 15 
26.05 
1.98 
undet. 
.54 
8.70 
4.79 
1.56 
.13 
.64 
.13 
100. 67 
