Prof. Beck on Igneous Action, as exhibited in New York. 335 



stone, &c. ; nor can their occurrence be often accounted for by 

 any supposition of their having formed part of more ancient rocks, 

 which by disintegration yielded them to the watery currents con- 

 cerned in accumulating the primary strata; for they are in gen- 

 eral, perfectly crystallized among fragmentary scales of mica, and 

 worn and broken feldspar and quartz, or granular aggregates of 

 those substances, scarcely diifering in arrangement or aspect of the 

 parts from particular sandstones and coarse argillaceous slates."* 



In the gneiss of New York and Westchester counties, which 

 often abuts the dolomitic beds, garnets frequently occur, but they 

 are seldom perfectly crystallized, being more or less rounded, either 

 by attrition or fusion. This is strikingly exhibited in the vicinity 

 of Yonkers, in Westchester, where these rounded garnets are very 

 abundant in the gneiss, and are from one fourth to three fourths 

 of an inch in diameter. Here too, large masses of garnet have 

 been found ; in one instance nearly a foot in diameter, and firmly 

 attached to the rock on all sides. In the more crystalline parts of 

 this formation, as at West Farms and New Rochelle, the garnets, 

 much less abundant, however, do not exhibit this peculiarity in 

 so decided a manner, but they are seldom well crystallized. 



In the vein of coarse granite in the town of Greenfield, Sara- 

 toga County, celebrated for the occurrence of chrysoberyl and 

 other minerals, the garnets have a trapezoidal form, but perfect 

 crystals are almost unknown. And the same remark will apply 

 to the small pink garnets found in the gneiss of the Noses, in 

 Montgomery County. Indeed, although I have seen a great 

 number of specimens from all the preceding localities, I do not 

 recollect ever to have met with a perfect crystal. 



Garnet, in almost every variety of color, is abundant at several 

 localities in Essex County ; as Rogers' Rock, Lewis and Wills- 

 borough. But crystalline forms are exceedingly rare, and are 

 found only in the rifts and fissures of the rock. 



I think myself warranted in the assertion, that throughout the 

 state of New York, when garnets occur in gneiss or in granitic 

 veins, they are imperfectly crystallized ; and in many, if not most 

 cases, they present the appearance of having undergone some 

 change through the influence of heat or otherwise, subsequently 

 to their original crystallization. 



* Treatise on Geology, II, 103. 



