1892.] NEW YOEK ACADEMY OF SCIENCES. 129 



biotite, sometimes bleached, green idiomorphic hornblende, a very 

 scarce aug-ite 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. 



III. 



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 lateiy 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, it is 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, allotriomorphic grou})ing. 



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 CaCOg used in the determination of the alkalies some 

 sodium was shown by the spectroscope. 



> Albany Granite and its Contact Phenomena. A. J. S., Jan. 1881. 



