88 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
5. ROCKS OF PIGEON POINT, MINNESOTA. 
[no. 228. 
Described b}^ 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. Oli vine-diabase. Hesso.^e. Contains labradorite, olivine, pyrox- 
ene, apatite, and magnetite. Analysis by W. F. Hillebrand, record 
No. 496. P. R. C. 107. 
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. 
Adamellose. Contains red feldspar, quartz, hornblende, chlorite, mag- 
netite, apatite, and rutile. Analysis by W. F. Hillebrand, record No. 
500. P. R. C. 1018. 
A. 
B. 
C. 
Si0 2 
49. 88 
18. 55 
2.03 
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 
ALA 
13.58 
Fe 2 3 
3.11 
FeO 
8.68 
MgO 
2.87 
CaO 
2.01 
Na 2 
3.56 
K 2 
3.44 
H,0 
2.47 
Ti0 2 
1.98 
1.75 
P 2 5 
.29 
Zr0 2 
MnO 
.13 
SrO 
trace 
BaO 
.04 
Li 2 
trace 
CI 
trace 
100. 12 
98.49 
99.91 
