IGNEOUS AND CRYSTALLINE ROCKS. 51 
E. Feldspar separated from gabbro, sec. 14, T. 44 N., R. 4 W., Wisconsin. 
F, G. Feldspars separated from olivine diabase, NE. } sec. 13, T. 45 N., R. 1 W., 
Wisconsin. P. R. C. 1003. 
E. F, G. 
The following analyses, by W. F. Hillebrand, of separations from the gabbro of 
Ashland County, Wis., were made for the late R. D. Irving, but were never published 
by him: 
H. Magnetite, record No. 687. Partial analysis. 
I. Feldspar, record No. 688. 
J. Diallage, record No. 686. 
For convenience I also include here, although it is decidedly out of classification— 
K. Graywacke, Hurley, Wis. Described by Bayley in Bull. 150, p. 84. Analysis 
by H. N. Stokes, record No. 1314. Contains quartz, feldspars, iron oxides, and 
probably kaolin. In the cement are chlorite, quartz, magnetite, pyrite, rutile, occa- 
sionally biotite, and either muscovite or kaolin. P. R. C. 20. 
89.46 | 100.14 | 100.41 | 100.18 
6. PIGEON POINT, MINNESOTA. 
Described by Bayley in Bull. 109. Also partly in Am. Jour. Sci., 3d ser., vol. 37, 
p. 54. A and B are also described in Bull. 150, p. 274. 
A. Olivine diabase. Hessose. Contains labradorite, olivine, pyroxene, apatite, 
and magnetite. Analysis by W. F. Hillebrand, record No. 496. P. R. C. 107. 
B. Diallageseparated 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, magnetite, apatite, and rutile. 
Analysis by W. F. Hillebrand, record No. 500. P. R. ©. 1018. 
