THE GREAT CENTRAL SYXCLINE. 233 



through these near their western border, and a broad band of the mica- 

 schists (/) separating them from the gneiss on the east. 



As they pass into Enfiehl both these faults become less effective On 

 the west the Monson gneiss is no longer brought up to form the western 

 border of the band of schists, but these are permitted to come into normal 

 relations with the Pelham band beneath the sands of the West Branch, the 

 two forming a double syncline of much regularity. The fault, however, 

 seems to continue due south across the whetstone-schists, directly toward 

 Enfield village, and it is mai'ked noi'th of this village by a line of crushed 

 rock full of comby quartz, which runs down west of the amphibolite and 

 between the two roads running north from the village, near the house of 

 J Tha^^er. On the east the amphibolite (d) appears again, and toward 

 the southern part of Enfield the Rowe two-mica-gneiss (b) also comes up 

 from below the latter. 



At this point the band comes under the infliience of the Belchertown 

 tonalite and passes down its eastern border, through Ware and Palmer, 

 greatly faulted and metamorphosed, so that its description is connected with 

 the discussion of the contact metamorphism effected by the tonalite (p. 243). 



South of this it becomes the West Monson syncline, which is more 

 naturally associated with the other bands east and west of it and is discussed 

 in a later section of this chapter (p. 24:9). 



PETROGRAPHICAL DESCRIPTION.S. 



The basal bed of the series (Rowe) is wanting through nearly the 

 whole area. Where it reappears, in the south part of Enfield and Ware, it 

 is a coarse musco-vite-gneiss, as in Pelham. The amphibolite requires no 

 special description. The whetstone-schist (Savoy), usually a gray whet- 

 stone, becomes in North Prescott, near H. Stetson's, a flat-fissile sericite- 

 schist with large garnets (15-20""°), which change externally into coarse 

 chlorite. It coi-responds exactly with the same rock west of the river — the 

 typical Savoy sericite-schist — with which it is here paralleled. Farther 

 south, near A. Gilbert's, it becomes a snow-white quartzite divided by very 

 broad, whitish (sericite) films. 



In Enfield, north of School No. 4, it is the same as above, but very 

 greatly contorted. In the south of Enfield, on the east flank of Quabin 

 Mountain, it appears in great force as a snow-white, granular quartzite, 



