350 Spodumene and its Alterations. 



the crystal sharply defined, but with the termination obliterated. 

 They are more or less intermingled with scales of mica, or cov- 

 ered by it in a thin film, and often are only the continuations 

 of those described under III, of which they are mere varieties. 



Paragexesis of Spodumexe. 



The paragenetic relationships between Spodumene and its 

 original associates in these granite veins, previous to its altera- 

 tion, will be more' fully discussed in another paper ; but the fol- 

 lowing brief statement will have a bearing on the present 

 purpose. 



In the two Goshen veins, they can be only imperfectly studied, 

 from the partially concealed outcrops, though better from the 

 abundant fragments. In the more easterly locality, the vein- 

 stone consists mainly of a coarse aggregate of Albite, Indicolite, 

 Garnet, and Spodumene, whose crowded and imperfectly outlined 

 grains indicate a more rapid crystallization than in the other 

 localities. In the Barrus vein, to the west, the mass of the vein 

 seems to be represented in place by a coarse aggregation of white 

 Quartz, Orthoclase, Muscovite, and occasionally greenish Beryl ; 

 while the scattered boulders of albitic granite appear to be frag- 

 ments of a central band or secondary vein, whose slow crystalli- 

 zation is suggested by the beautiful aggregate of snow-white 

 Cleavelandite and grayish-white Quartz, which forms the matrix 

 of the rarer minerals. Of these, the most abundant are the 

 Spodumene, whose habit has been already described, and Tour- 

 maline, black, green, or blue-black (Indicolite), generally massive, 

 but sometimes in good crystals. Less commonly were found 

 Beryl, green, and white (Goshenite), in grains, or sometimes 

 fairly crystallized with good terminations, Garnet, rose-colored 

 Muscovite, and still more rarely Columbite and Cassiterite in 

 minute crystals. Apparently there has been also, in parts of the 

 vein, a filial deposition of masses of smoky quartz, enveloping 

 smaller crystals of these minerals, but particularly of green Beryl 

 and Indicolite. 



At Macomber's Ledge in Chesterfield, the coarse Orthoclase- 

 granite of the main vein contains films of Margarodite and a 

 few imperfect green Beryls ; while in the secondary vein the 

 succession appears to have been; first, Quartz, Muscovite, granu- 



