THE CHESTER AMPHIBOLITE AND SERPENTINES. 95 



The soapstoue has been worked by the Indians. Half-made pots are 

 still to be seen on the surface, and an Indian an-ow was found, on blasting, 

 12 feet down in a narrow crevice in the limestone. 



To the north of the quarry the l)ed of granite cuts oiF the serpentine 

 band, but it reappears after an interruption of a rod. 



Followed a few rods south, the western contact of the bed is exposed 

 by digging. It is a thick bed of rich-green, coarse-radiuted actinolite mixed 

 with biotite, and the wall on the left is granite with some jilagioclastic fringe 

 rock containing biotite and tourmaline. Nearly the whole thickness of the 

 bed here is black serpentine, but Professor Crosby pointed out to me a 

 continuous valley, generally quite swampy, which may be occupied by the 

 limestone and caused by its solution. 



At the southern outcrop mentioned above (and at several other places) 

 a black, flat amphibolite accompanies the serpentine on the east, but does not 

 seem to be in great force. Here the radiated tremolitic character of the 

 soapstone is specially manifest. It forms a heavy bed on the east, followed 

 westerly by a thin-foliated verd antique, made of bands of blackish-green 

 serpentine and white marble, with about 20 feet of the black serpentine to 

 the west before the schist is reached. 



Farther south the rock crops out in the bed of Westfield Little River 

 (bed No. 19), and in Westfield (bed No. 20) nox-th of the Granville road, 

 near the west border of the New Red sandsone;^ south of this road it crops 

 out in the hill back of S. Drake's house (bed No. 21), where it is very coarse- 

 grained, exactly like the East Granville locality, and from the weathering 

 out of the calcite, which fills the interstices, it is very rough-sm-faced; and, 

 finally, it is seen in the bottom (bed No. 22) of Munn's brook, near the line 

 between Granville and Southwick. It is in place where the brook emerges 

 from its gorge in the hills. The prevailing rock is a black enstatite-serpen- 

 tine; amphibolite is subordinate. The line of strike then carries the bed 

 beneath the sands of the Westfield plain and it is not seen farther south. 



FAULTS AND SERPENTINIZATION. 



The great Hoosac fault displaces the rocks a mile on either side of the 

 Deerfield River, below its bend at the mouth of the Hoosac Tunnel. It seems 

 possible that this fault plane had a determining influence in the great devel- 



• Hitchcock, Geology of Mass., 1841, p. 159. 



