THE MOUXT TOBY CONGLOMERATE, 3G3 



hill, a hundred rods north, are a coarse, jjebbly sandstone, derived almost 

 wholly from this peculiar rock. 



All around the south border of the gneiss the outcrops of the junction 

 are very fine, and one can see the ledge undisturl)ed, passing gradually 

 through the stages described above at Whitmores Ferry until, at a distanc^e 

 of a few rods, a coarse conglomerate is formed, in Avhicli I measured one 

 egg-shaped block 47 inches long; and in the whole hill to the south for 

 miles the large glacial bowlders of this rock are so abundant that I 

 searched specially for an outcrop of the older rock, and found it here. 

 The conglomerates are thrown off" in all directions from this mass, and in 

 the brook dip 30° E., away from the hill. The gneiss bowlders weather 

 more rapidly than the fine paste, and form great holes in the conglomerate. 



At the most northern point in the south wood road, on Mount Tobv, 

 is probal)ly another similar outcrop, as pebbles 40 to 45 inches occur, and 

 3 rods east of the east end of this road is another outcro]) of a fine granite 

 protruded through the conglomerate. 



Breccia at North Amherst — Just east of the North Amherst railroad 

 station, in a pasture a few rods southeast of the point where the road turns 

 south, and at the Golden Gate dam, a half mile east, occurs a coarse, rust\- 

 breccia of gneiss pebbles and quartz and feldspar grains. 



In one slide a large pebble of an even-bedded Ijiotite-gneiss is embedded 

 in finer material. In another many rounded grains of a fine-grained gneiss, 

 often cracked and distorted, appear in a clastic paste. This has in manv 

 places the appearance of a coarse conglomerate distorted by 2:)ressure, and 

 I was at one time inclined to consider it a portion of the mica-schist, gneiss, 

 and gi'anite crashed in place, recemented, and much weathered. In places 

 it is shot through with calcite veins. 



As soon as I had studied the contact of the Triassic conglomerate on 

 the gneiss at the exposure west of Montague Center, I was struck by the 

 similarity of the two, as well as by the resemblance of this occurrence to 

 that at the Williams farm, at Bernardston. It seems, then, to be the contact 

 layer of the Triassic conglomerate on the granite. 



ACTION OF ICE IN THE TRIAS. 



All these contacts present peculiarities which strongly suggest the 

 presence of ice during the formation of the coarse breccias, especially the 

 Whitmores Fen-y beds. It is very hard to understand how the large 



