1892. | NEW YORK ACADEMY OF SCIENCES. 129 
biotite, sometimes bleached, green idiomorphic hornblende, a very 
searce augite or two, large zonal plagioclase, and magnetite. The 
ground-mass is glassy. 
No. 6, from near the Kane Springs Mine, is a most excellent 
andalusite hornstone. The little chiastolite crystals, up to a milli- 
meter or two in diameter, exhibit the dark crosses in the greatest 
perfection. There are also the indistinct beginnings of many others 
to be seen. They are set in a matrix which is without doubt an 
altered slate. The rock must have come from an altered zone of 
slate, near the contact with igneous rock. In this country anda- 
lusite in such relations has already been noted in the Willey Notch 
of the White Mountains as described in Hawes’s classic paper,' and 
in less characteristic schists by G. H. Williams from the contacts of 
the Cortlandt series on the Hudson. In large crystals it is well 
known at Lancaster, Mass., but special petrographic descriptions 
remain to be written so far as known to the writer. 
tat. 
On the Granite Quarried at Chester, Mass. Some facts in regard 
to the granite quarried by the Hudson and Chester Granite Co. at 
Chester, Mass , have lately come into my possession, and as they 
have both petrographical and economic bearings, they are here re- 
corded. . The interest attaching to building-stones and all reliable 
data regarding them will make the crushing-tests of value. 
The granite is a very homogeneous, rather finely crystalline stone, 
of a bluish-gray color on polished faces and a much lighter tone on 
hammered ones. It is a true granite, being formed of quartz, ortho- 
clase, green biotite, and muscovite in largest part with plagioclase 
and microline likewise present. There is almost no magnetite what- 
soever, and in the slides no pyrite showed, although a few minute 
points could be found in the rock fragments, but, as the analysis 
shows, itis almost lacking. A sprinkling of titanite is present which 
has been derived from titaniferous magnetite, as a small core is now 
and then recognizable. Epidote, secondary after biotite, is occa- 
sionally met. All these minerals are intermingled in a very com- 
pact, allotriomorphie grouping. 
An analysis which is the mean of two closely agreeing duplicates 
is appended. It was made by Professor L M. Dennis, of Cornell 
University, and the soda is given by difference, because in the 
NH,Cl and CaCO, used in the determination of the alkalies some 
sodium was shown by the spectroscope. 
1 Albany Granite and its Contact Phenomena. A. J.S., Jan. 1881. 
