82 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
pBULL. 168. 
F. Average gabbro, south quarter post, sec. 35, T. 61 N., R. 12 W. 
Described by Bayley in Journal of Geology, vol. 1, p. 688. Contains 
plagioclase, olivine, pyroxene, and magnetite. Analysis by H. N. 
Stokes, record No. 1267. 
G. Feldspar from preceding gabbro. Analysis b}^ W. F. Hille- 
brand, record No. 1308. 
H. Feldspar from gabbro, east side of North Fowl Lake. Analysis 
by Hillebrand, No 1308. 
I. Feldspar from gabbro, NW. i of SE. ± of sec. 23, T. 62 N., R. 10. 
J. Feldspar from gabbro, center of sec. 25, T. 64 N., R. 8. 
K. Feldspar from gabbro, Duluth and Iron Range Railroad. 
Analyses I, J, and K by Hillebrand, record No. 1115. 
H, I, J, and K analyzed for W. S. Bayley, but analyses hitherto 
unpublished. 
F. 
G. 
H. 
1. 
J. 
K. 
Si0 2 
46.45 
21.30 
.81 
9.57 
7.90 
9.83 
2.14 
.34 
.14 
1.02 
1.19 
.02 
.04 
trace 
51.89 
29.68 
.32 
.37 
.38 
12.62 
3.87 
.50 
.07 
.39 
62.71 
19.20 
1.08 
.93 
.81 
.44 
2.96 
10.41 
.23 
.92 
trace 
52.50 
30.15 
.47 
.15 
.10 
12.82 
3.72 
.53 
| .25 
trace 
52.61 
29.80 
.57 
.23 
.20 
12.25 
3.80 
.53 
| .29 
trace 
53.45 
29.77 
.33 
- .15 
.11 
11. 33 
4.33 
.68 
} .23 
trace 
A1 2 3 
Fe 2 3 
FeO 
MgO 
OaO 
Na 2 
K 2 
H 2 at 100° . . . 
H 2 above 100° 
Ti0 2 
P,(X 
NiO 
MnO 
trace 
trace 
trace 
SrO 
100. 75 
100. 09 
99.69 
100. 69 
100. 28 
100. 38 
