114 GEOLOGY OF OLD HAMPSHIEE COUNTY, MASS. 



22. Ensfatite-serpentine. — Westfield. Prolonging' the line of the Atwater 

 bed in Russell southward, it is found that many large bowlders occur where 

 it crosses the road to Grranville, and farther south an immense block lies in 

 the woods on the hill back of S. Drake's house, in the west parish of 

 Westfield, which is made up of very large enstatite crystals in every stage 

 of change to bastite, and the whole mass is exactly like that described 

 above at J. Downey's, in West Granville. 



Farther south, along Munn's brook, where it cuts a deep gorge in 

 Sodom Mountain, at the head of the gorge, near the house of H. H. Pur- 

 chase, and at the mouth of the same, are many great bowlders of a similar 

 black serpentine with large crystals of enstatite changing or changed into 

 bastite or white talc. All these occurrences, to this last by Munn's brook, 

 are so similar that a single description of slides cut from the great bowlder 

 at H. H. Purchase's, Granville, may serve for them all, and this occun-ence 

 is so like that near J. Downey's, in West Granville, that the description can 

 be brief, as I shall note only the important differences. 



Slides of the freshest enstatite show a reddish-yellow color and polarize 

 brilliantly. Some of them contain very abundantly the stout, straight 

 black rods ; in others they are as rare as in the former locality. Magnesite 

 in rounded grains and distinct rhombohedra is found abundantly in the 

 freshest enstatite, apparently as a primary constituent, A qualitative 

 examination determined the absence of calcium. With cold hydrochloric 

 acid fragments of the serpentine presented no change; with boiling acid 

 there was a long-continued effervescence, and there remained an interlaced 

 mass of altered enstative crystals. 



23. "Dia/Jarje in serpentine. — Sodom Moimtain." XIII, No. 48, Massa- 

 chusetts Survey Collection. The specimen is wanting in the collection at 

 Amherst, but it must have come from one of the latter localities along the 

 gorge of Munn's brook, through Sodom Mountain, and must have been an 

 enstatite and not a diallage rock, the latter mineral not occurring in the 

 serpentine range. 



In the long line of outcrops from Zoar to North Blandford the serpen- 

 tine is characterized by deep oil-green colors, marked translucence, and 

 freedom from secondary magnetite. It is composed of fine serpentine blades 

 mingled with softly irised films of talc, and still contains the scattered grains 



