590 GEOLOGY OF OLD HAMPSHIEE COUxN^TY, MASS. 



drift hill on the west, while at a much lower level the high terrace of the 

 Connecticut Lake swings round the drift hill on the west and south. This 

 was the last chapter in the history of the stream. This delta was caused 

 by a breaching of the stream at this point by the melting back of the ice to 

 leave a small temporary lake in its course, in the angle in which Dwight's 

 station now lies, for the stream during its earlier stage seems to have flowed 

 across this depression upon the surface of the ice, and its heavy sands are 

 continuous at the proper level along the flank of the Pelham Hills east of 

 Dwiglit's station, across from the delta to the sands of the Belchertown Pass, 

 and a section of them is figured and described in the section on kettle-holes 

 (p. 665). Through the Belchertown Pass it threw down the abundant 

 sands and gravels which stretch from Avail to wall of the pass and extend 

 through its entire length. Their greatest height is 337 feet, though many 

 kettle-holes, some of the largest size, disguise the original level of the 

 sands. The three Belchertown ponds occupy three of these depressions. 



The railroad cuttings showed most confused and tortuous stratification, 

 abrupt alternation from fine sand in great mass to the coarsest gravel, great 

 bodies of fine sand standing with the bedding almost vertical, as if they had 

 been undermined when frozen, and kettle-holes, some partly and some 

 wholly filled up by later sands, as if the ice beneath had melted away while 

 the floods were still in progress. 



We may at this point imagine, for the sake of clearness, the following 

 stages in the retreat of the ice from the Springfield Lake basin, or the 

 Granby basin, which is a part of the former, premising that the ice would 

 disappeai- south of the mountain much earlier than north: (1) When the 

 ice had only melted away from the eastern rim, so as to make a waterway 

 continuous south from the Belchertown notch along the foot of the 

 eastern valley rim ; (2) when the ice had melted away from the south face 

 of the Holyoke range ; (3) when the ice had melted back from the nortli 

 face of the same range for a small distance. We imagine the ice to still fill 

 the whole valley of the Connecticut and to prevail over the western hills, 

 but to have disappeared from the eastern. 



1. In the first case the waters passing through the Belchertown notch 

 would have continued southward, and we find, after a brief iuterraptiou, 

 coarse kettle-holed sands, which commence at P. Chandler's, opposite the 

 lower pond, at 326 feet above sea, and are quite continuous across Granby, 



