232 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



soon merges into the coarser, less graphitic, rust}', garnetiferous schists 

 common farther north. 



Ai-ound New Salem Center it is greatly cut by granite and carries 

 several bauds of ami^hibolite, and bowlders of a pyroxene-garnet rock 

 occur, which indicate the former presence of limestone. All this area of 

 the schist, except as mentioned above, lies to the west of the line akeady 

 given as the boundary of the occurrence of fibrolite, and this mineral was 

 not observed at all in New Salem; but the band of mica-schist which runs 

 down from New Salem village carries this mineral soon after it passes over 

 into Prescott. 



Structure. — An inspection of the map will show that the band crosses 

 the north line of New Salem, after disengaging itself from the Walnut Hill 

 anticline, as a simple syncline, and continues thus to the middle of the 

 town, where an upfolding of the whetstone-schists (e) separates the mica- 

 schists (/) into two parts, and a little farther south this upfolding brings 

 up also the amphibolite (f/), which runs down to the east of the large 

 diorite area and seems to end upon an eastward prolongation of the great 

 Pelham cross-fault, and I have so represented it. 



The western and broader portion into which the mica-schist (/) is thus 

 divided contracts rapidly and sends a nari-ow lobe down west of the dio- 

 rite mass into Prescott, where it ends. All these irregularities stand in 

 relation to this great mass of diorite, as appears jjlainly from an inspection 

 of the map, and prove that it was present passively dm-ing the upfolding of 

 the rocks, preventing the continuance southward of the regular syncline 

 in New Salem already described. Indeed, a further irregularity appears 

 east of the north end of this diorite mass, in that the three lower members 

 of the series disappear, and the mica-schists can be for a long distance seen 

 resting directly upon the g-neiss to the east. 



PRESCOTT AND ENFIELD. 

 STRUCTURE. 



Across Prescott the band continues unchanged. It is bordered on the 

 east and the west by faults which separate it from the Monson gneiss (a) 

 and conceal the two lower beds. The surface is thus mostly occupied by 

 the whetstone-schists (e — Savoy schist), the amphibolite {d) coming up 



