THE noosAC S(^nisT. 73 



gneiss, but still filled with the small tortuous quartz veius, and diflfering 

 from the Becket g-neiss below by tlie presence of two micas, the muscovite 

 being the preA-ailing variety. In the village itself, but a few rods farther 

 west, the true Becket gneiss appears and occupies all the region westward 

 with exactly the same strike and the same high dip, and though the exact 

 line of contact is not exposed, there is nothing to suggest unconformity. 

 Everything here points to a gradual passage of the gneiss up into the 

 hydromica-schist. On the other hand, the rocks here all stand vertical side 

 by side and have been subjected to the greatest compression, and the traces 

 of an unconformity of considerable importance may well be masked. 



However, going south from the railroad across Becket, Blandford, and 

 Tolland, along the winding junction line of the two formations, one finds 

 marked evidence of a considerable unconformity, in that while the newer 

 formation conforms in strike to the undulations of the boundar}' Hue, dip- 

 ping away from it to the east, the strike of the older is in all this distance 

 uniformly N. 40° to 45° E., almost at right angles to the boundary, and 

 thus to the strike of the newer rocks. 



I conclude that the unconformity between the two formations is 

 general, and that the feldspathic character of the lower half of this forma- 

 tion is due to its derivation from the older gneisses, against Avhich it rests 

 in the form of a coarser, feldspathic material, while the upper portion was a 

 more arenaceous sediment, largely deprived of its alkaline constituents, and 

 this conclusion seems to me strengthened by the study of the same junction 

 on the east side of the Connecticut. 



THE GRANVILLE AREA. 



This area comprises Blandford, Tolland, and (Iranville, in Hampden 

 County, and Hartlaud and Granbv in Connecticut. 



South of the railroad section given abo\e, along tlie south line of Mid- 

 dlefield, the feldspathic mica-schist continues across Becket in Berkshire 

 C'ounty to its southeast corner, and there it entei-s the Granville quadrangle at 

 its northwest corner, and at the same time Hampden County. Its relations, 

 especially to the Rowe schist above, can best be studied on the road west 

 from Chester, where the pale greeni.sh-gray hydromica-schist (Rowe schist) 

 succeeds the horuldende-schist as one goes west from the Emery mine, 

 and is well exposed at the iron watering trough. Jixst beyond the first 



