P. Red granitic rock resembling D, but with more dark spots, found in contact with the purplish slate, N. Liparose. Consists mainly of red feldspar, quartz, and chlorite. Analysis by J. E. Whitfield, record No. 519. Dried at 104°. P. R. C. 1014.

Q. Groundmass of red mottled quartzite. Analysis by W. F. Hillebrand, record No. 499. P. R. C. 1022.

R. Green mottlings from Q.

by Hillebrand, record No. 498.

Mostly quartz and sericite. Analysis

S. Another sample of the green mottlings, selected with especial care. Analysis by L. G. Eakins, record No. 1058.

T. Brilliantly red vitreous quartzite. Analysis by R. B. Riggs, record No. 574. Dried at 105°. P. R. C. 1008.

6. MESABI DISTRICT, MINNESOTA.

The following rocks, described by Leith in Mon. XLIII, do not fall legitimately within this section of the present bulletin. There seems, however, to be no other convenient place for them, and so the niceties of classification have been ignored for reasons of expediency.

A. Greenalite rock, test pit, Cincinnati mine. Contains green and brown transparent granules, with opaque brown to black ones, in a matrix of chert.

B. Greenalite rock, same locality as A. Contains greenish yellow granules, slightly altered to amphibole in a matrix of amphibole with subordinate chert.

C. Greenalite rock, near W. quarter post, sec. 35, T. 59 N., R. 15 W. Resembles A.

D. Greenalite rock, near SE. corner of sec. 22, T. 59 N., R. 15 W. Contains yellowish-brown, transparent, and dark-brown to black and opaque granules in a matrix which is mainly amphibole, possibly actinolite. All four rocks contain oxides of iron, either limonite or magnetite.

Analyses by George Steiger, record Nos. 1931 and 1992. In three of the rocks the portions soluble and insoluble in hydrochloric acid were analyzed separately.

E. Ferruginous chert, sec. 28, T. 58 N., R. 17 W.

F. Ferruginous chert, horizon of ore deposits, Oliver mine.
G. Amphibolitic chert, Old Chicago mine.

H. Amphibolitic chert, one-half mile southwest of Virginia.
I. Amphibolitic chert, Donora mine.

G, H, and I are largely amphibole in a matrix of chert. Analyses by George Steiger, record Nos. 1931, 1948.

7. MISCELLANEOUS ROCKS FROM MINNESOTA.

A. Granulitic hypersthene-gabbro, from SE. ‡ of sec. 20, T. 65 N., R. 4 W. Cookose. Described by Bayley, Journal of Geology, vol. 3, p. 1. Contains hypersthene, biotite, diallage, magnetite, and plagioclase. Analysis by H. N. Stokes, record No. 1267.

B. Hypersthene from A. Analysis by E. A. Schneider, record No. 1358.

C. Granulitic diallage-gabbro, SE. of NW. of sec. 26, T. 64 N., R. 8 W. Auvergnose. Described by Bayley, Journal of Geology, vol. 3, p. 1. Contains diallage, hypersthene, magnetite, and plagioclase. Analysis by W. H. Melville, record No. 1403.

D. Olivine-gabbro, west side of Birch Lake, SE. of sec. 19, T. 63 N., R. 4 W. Auvergnose. Described by Bayley, Journal of Geology, vol. 1, p. 688. Contains a large proportion of diallage and olivine. Analysis by Stokes, No. 1267.

E. Olivine from D. Analysis by W. F. Hillebrand, record No. 1308.

F. Average gabbro, S. quarter post, sec. 35, T. 61 N., R. 12 W. Hessose. 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 by W. F. Hillebrand, record No. 1308.

H. Feldspar, from gabbro east side of North Fowl Lake. Analysis by Hillebrand, No. 1308.

I. Feldspar, from gabbro, NW. of SE. of sec. 23, T. 62 N., R. 10 W.
J. Feldspar, from gabbro, center of sec. 25, T. 64 N., R. 8 W.
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.