THE CHESTER AMPHIBOLITE AND SEHPENTINES. 81 



amphibolite 6 rods wide and 10 rods of swampy ground, probably in 

 whole or part underlain by steatite (bed No. 3). Then comes the dark- 

 green serpentine, which is here 35 rods wide, and it is followed immedi- 

 ately by black, thin-fissile amphibolite. This is so clearly a repetition of 

 the series at the soapstone quarry given above that a fault, substantially 

 as shown on the map, is quite certainly present. 



Where the beds cross the road to the sov;th they are covered, and 

 continue so as far south as I could penetrate in this wilderness. 



At latitude 42° 35§', longitude 72° 55f ', the amphibolite appears again, 

 and the line of boundary is drawn approximately from the strike between 

 these points, as the amphibolite could not be found and the sericite-schists 

 above and below the amphibolite are hardly distinguishable. Indeed, at 

 the cross-roads a mile north of the last locality the sericite-schist is 

 almost continuously exposed, but careful search failed to disclose any 

 amphibolite. 



From the last locality the amphibohte makes a bend to the east and 

 cuts across the shai-p curve in the road next south. On entering the 

 Chesterfield quadi'angle, the amphibolite, where it crosses the road near 

 Swift River, in Windsor, is changed to steatite (bed No. 4), and at Jordans- 

 ville the schist is well exposed in the brook southwest of the \'illage. 



HAMPSHIRE COUNTY. 

 THE MIDDLEFIELD SEKPENTINE. 



Reentering the county, the amphibolite appears just west of the village 

 of West Worthington, and can be traced thence southward. At H. Smith's, 

 in the northwest of Middlefield, it has on the east a fine dejjosit of seii:)en- 

 tine (bed No. 5), bordered on the east by talc. Along the east side of a 

 band of the common amphibolite rests a mass of dark-green serpentine, and 

 next east a great mass of steatite, often can-ying large nodules of the finest 

 dolomite suirounded by delicate-green talc, and on the east sericite-schist 

 folds around the great boss of steatite, as if it had been present — or, rather, 

 as if the rock of which it has been formed had been present — as a foreign 

 and resistant body during the compression of the schists. The steatite is 

 here 66 feet wide, and it furnishes the best material in its upper half. It 

 is opened in a quany 41 feet wide and 82 feet long, and is separated from 

 the amphibolite opposite the quan-y by only 16 feet of covered space; so 



MON XXIX (i 



