318 Spodumene and its Alterations. 



XXVIII. — On Spodumene and its Alterations, from, the granite- 

 veins of Hampshire Count//, Mass. 



BY ALEXIS A. Jl'LIEN. 

 Read June 10th and November 18tb, 1878. 



The mineral Spodumene is one of rather scanty occurrence, in 

 regard both to abundance and to the number of its known 

 localities. In Europe, it has been reported from only a half- 

 dozen places in Scotland, Ireland, Sweden and the Tyrol ; in 

 this country, in only four localities outside of Massachusetts ; 

 but, in the eastern part of that State, it occurs at Sterling, and 

 in crystals of remarkable size and perfection, at six localities, 

 within Hampshire County in the western part. Here, as usual, 

 it was found in coarse granite veins — huge lenticular masses of 

 that rock, with sometimes great extension but little thickness — 

 succeeding each other at intervals of several miles, along the 

 strike and enclosed between the highly-tilted beds of the stratum 

 of Staurolitic mica-schist. This is one of the lowest members of 

 the group of crystalline schists of that region, consisting in de- 

 scending order of the following series : 



1 — Chloritic, Hornblende, and Talc Schists, enclosing layer- 

 veins of Magnetite. Rhodonite, Entile, Zoisite, Emery (at 

 Chester), Margarite, Diaspore, etc. 



2 — Micaceous grits, often slaty, fine-grained, siliceous, and 

 arenaceous, with quartz-veins, mostly barren of minerals. 



3 — Ottrelitic Clay-slate, the well-known Phyllite of western 

 Massachusetts : frequently intersected by heavy veins of milky- 

 white quartz, of which the smaller sometimes carry blue Kyanite, 

 Graphite, Cummingtonite, etc. 



4 — Staurolitic Mica-schist, rich in Garnets and more rarely 

 Kyanite : everywhere marked by the intercalated layer-veins of 

 coarse Orthoclase-granite. with Beryl. Several of these embrace 

 secondary veins of albitic granite, containing a large variety of 

 interesting minerals afterwards enumerated. 



5 — Granitoid gneiss, generally in heavy-bedded, coarse masses, 

 rich in Orthoclase. 



