622 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



that starts at the mouth of Fall River Valley, in the Bernardstou i)ienic 

 o-rove, runs south, risinj? over a col between two drumlins east of the 

 road to Greentield, at a much higher level than the jilain to the west, here 

 described as the old course of Fall River, which was at that time still filled 

 with ice. It can be seen further from this section that the alnnidant flow 

 continued after the waters had ceased to flow from the main cliannel 

 through the Bernardston Pass. An inspection of the map will make it clear 

 that the deep Fall River Valley must for a long time have been a main 

 artery of drainage. 



When the waters went through the Bernardston Pass the ice had most! 3^ 

 • melted far north up the main valley ; but a remnant was submerged beneath 

 the sands along the border of the stream in West Northfield, causing the 

 kettle-holes of the western border of the Bennetts Brook plain (see p. 617), 

 and through the pass the waters spread their gra-v^els over a, considerable 

 but gradually diminishing body of ice. At the same time the great volume 

 of water which came down the valley of Fall River also flowed over ice, 

 and thus were formed the esker ridges of argillite pebbles which project 

 out from this valley and blend with the gneiss gravel brought through the 

 pass from the main valley. A great mass of ice filled the basin of Gill, and 

 thus completed the walls of the pass and prevented the flood from filling 

 this basin, as they naturally would have done. 



When the flood had so far receded that the waters of the main stream 

 no longer went through the pass, the waters of Fall River continued to 

 flow into the Greenfield basin, carrying a large volume of the kame sands 

 southward into this area and smoothing out the broad plain which still 

 extends between the two, until, by the sinking of the ice, its southeastern 

 border was breached and it found exit across the kame gravels south into 

 the drift region of Gill by way, apparently, of its reopened 2)i"e-Glacial 

 bed. 



THE BENCH ON THE EAST SIDE OF THE RIVER IN NORTHFIELD AND ERVING. 



The hills are set back on the east side of the valley at about the same 

 place as on the west side, and the high sands expand eastward across Hins- 

 dale and the corner of Winchester, in New Hampshire, up the valley of 

 the large Perchee Brook and continue southward with a width of 200 to 

 400 rods across Northfield and Erving. The rock surface is everywhere 



