Minerals in Greenstone. 



435 



also in West Springfield. But it is found on the west side of these 

 ridges ; as at a spot one mile east of the village of Deerfield, and at 

 another about the same distance nearly east of the village of Green- 

 field. No very rich specimens of this mineral, however, are met 

 with in our greenstone. 



Augite of an iron black color and in imperfect crystals or in veins, 

 is sometimes met with in the tufaceous greenstone of the Connecticut 

 valley: as at a spot one mile east of the village of Deerfield. 



Several varieties of the quartz family are found in the greenstone 

 of Massachusetts, principally in that of the Connecticut valley. 

 Limpid crystalized quartz is found frequently in the form of geodes, 

 and sometimes these crystals are amethystine of a delicate though 

 not very deep color. This amethyst has been observed one mile 

 east of the village in Deerfield : on the same range three miles south 

 of this spot and east of the village of Bloody Brook ; on Mount Hol- 

 yoke ; and in West Springfield. At the latter place the crystals are 

 sometimes smoky. (No. 1117.) 



The quartz that occupies the cavities of greenstone, as at a spot a 

 mile east of the village in Deerfield, is sometimes tabular ; and the 

 folia are quite thin and delicate. Sometimes it is radiated, and not 

 unfrequently it contains tabular or prismatic and radiating cavities, 

 once occupied by a mineral. The radiating cavities were perhaps 

 once filled with Thomsonite; at least, they resemble that mineral in 

 form. I have seen them three or four inches in length, and crossing 

 one another from different centers. 



Chalcedony is not an uncommon mineral in the greenstone of the 

 Connecticut valley. So far as I know it is wanting in the greenstone 

 around Boston : and this fact, with the almost entire absence of an 

 amygdaloidal structure, are marks of peculiarity well worthy of no- 

 tice. In the Connecticut valley the chalcedony is usually in small 

 nodules rarely more than one or two inches across. Most frequently 

 its color is milky or smoky gray, and sometimes it appears to be real 

 cacholong. At other times it is of a flesh colour, from the lightest to 

 the deepest shade forming carnelian. Rarely I have seen it yellow- 

 ish, and closely allied to sardonyx. These varieties are most common 

 in the greenstone range passing east of the villages of Greenfield and 

 Deerfield, and on its western face ; but rare on its eastern side. 



All the above varities of the quartz family are sometimes arranged 

 concentrically, so as to form agates. Generally they are small : but 

 some specimens found by Dr, Cooley in the south part of Deerfield, 



