G. Syenite-porphyry. Contains orthoclase, plagioclase, microperthite, hornblende, quartz, augite, magnetite, biotite, apatite, and zircon. H. Granite-porphyry. Composition like D, but with more quartz. I. Basic segregation in H. Contains hornblende, green and brown augite, biotite, quartz, microperthite, magnetite, little apatite, and

zircon.

J. Diorite. Contains hornblende, augite, biotite, plagioclase, titaniferous magnetite, sphene, zircon, and quartz.

M. Basic segregation in diorite. Contains hornblende, augite, biotite, plagioclase, magnetite, apatite, zircon, and a little quartz. N. Diabase. Contains plagioclase, augite, and magnetite.

O. Camptonite. Contains brown hornblende, plagioclase, a little augite, olivine, magnetite, and apatite.

P. Phyllite. Contains quartz, sericite, graphite?, magnetite, pyrite, rare orthoclase, plagioclase, sphene, and rutile.

Q. Microperthite-hornfels. Contains biotite, quartz, red garnet, corundum, magnetite, iolite, microperthite, and rarely pleonaste.

R. Cordierite-hornfels. Contains quartz, biotite, pleonaste, corundum, iolite, magnetite, plagioclase, red garnet, and epidote?.

In these rocks the sulphur is all reckoned as pyrite, although pyrrhotite also is probably present. The carbonic acid represents either dolomite or siderite; not calcite. Traces of lithia and strontia occur in nearly all. Samples H, L, O, and Q contain traces of copper. In there is 0.03 V,O,, a supplementary determination by Hillebrand.

2. MISCELLANEOUS ROCKS.

A. Amphibolite, Guilford. Described by Emerson in Mon. XXIX. Contains hornblende needles, with albite and rutile. Analysis by L. G. Eakins, record No. 1326.

B. Granitoid gneiss, north of Lincoln's.

C. The same, west slope of Little Peco.

D. Chloritic granite, East Clarendon section.

E. Hornblende-granite, East Clarendon section.

Rocks B, C, D, and E collected by C. L. Whittle, but not described. Analyses by H. N. Stokes, record No. 1396.

MASSACHUSETTS.

1. ROCKS OF THE CONNECTICUT VALLEY.

Described by Emerson in Mon. XXIX.

A. Serpentine derived from salite, Osburn's soapstone quarry, Blandford.

B. Dark-green, oily serpentine, center of large Middlefield bed. C. Enstatite, slightly altered, from Granville. For comparison with D.

D. Serpentine derived from enstatite, Granville.

Analyses A, B, and C by W. F. Hillebrand, record No. 1555. Analysis D by Geo. Steiger, No. 1536.

E. Rich, dark-green serpentine, Rowe.

F. Black serpentine containing marmolite, Atwater's quarry, Russell. G. Blackish-green serpentine containing much chromite. From "The Crater," North Blandford.

H. Gray, splintery serpentine, Chester.
Analyses by Steiger, record No. 1536.