76 
ANALYSES OF ROCKS, IT. S. GEOLOGICAL SURVEY. 
BULL. 168. 
5. ROCKS OF PIGEON POINT, MINNESOTA. 
Described by Bayley in Bull. 109. Also partially in Amer. Journ. 
Sci., 3d series, vol. 37, p. 54. A and B are also described in Bull. 
150, p. 274. 
A. Olivine diabase. Contains labradorite, olivine, pyroxene, apatite, 
and magnetite. Analysis by W. F. Hillebrand, record No. 496. 
B. Diallage separated from diabase. Partial analysis by R. B. Riggs, 
record No. 607. 
C. Rock lying between the diabase and the adjacent red porphyry. 
Contains red feldspar, quartz, hornblende, chlorite, magnetite, apatite, 
and rutile. Analysis by W. F. Hillebrand, record No. 500. P. R. C. 
1018. 
A. 
B. 
c. 
Si0 2 
49.88 
18. 55 
2.06 
8.37 
5.77 
9.72 
2.59 
.68 
1.04 
1.19 
.16 
none 
.09 
trace 
.02 
none 
trace 
48.34 
2.90 
4.68 
14.15 
11.34 
15.10 
57.98 
13.58 
3.11 
8.68 
2.87 
2.01 
3.56 
3.44 
2.47 
1.75 
.29 
A1 2 3 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 
Ti0 2 ! 
1.98 
P 2 5 
Zr0 2 
MnO 
.13 
trace 
.04 
trace 
trace 
SrO 
BaO 
Li 2 
CI 
100. 12 
98.49 
99.91 
