THE BBLCHERTOWN LAKE. 577 



We have been following up a tributary of the lielchertown Lake to 

 this place, and we find here that the ground drops away more than 150 feet 

 below its level. Looking north through the pass formed by the east end 

 of the Holyoke range and the continuation of the Belchertown ridge on 

 our right, we see that the latter ridge, just north of the pass and above 

 Dwight's station, runs behind (east of) a new ridge (the ridges stand en 

 dchelon in reference to the valley of the Connecticut, having, as they run 

 north, a little more easting than it). Between these ridges is a high valley, 

 in which is the continuation northward of the stream bottom we are follow- 

 ing, the two parts facing each other across the low pass of the Belchertown 

 ponds like the broken ends of a Roman aqueduct. A mountain brook has 

 now cut a deep gorge in this valley in till, which is almost as compact as 

 rock, but this is only a central notch in a flat-bottomed valley which ends 

 southwardly quite abruptly above Dwight's station, and which is, in fact, 

 the point in the eastern lobe just described (p. 576), where the breaching of 

 the channel deflected the outflow down the west of the ridge to our place 

 of observation. This channel is water-molded and covered with bars and 

 sand flats, exactly as is its southern portion in Belchertown, and one may 

 follow it up past the asbestos mine, east of which the rocky ridges are 

 smoothed into reefs and covered by gravel bars, until it merges into the 

 second great ten-ace (1 p, PL XXXV, C) of the Pelham basin. Standing 

 here, or, better, on the east end of the Holyoke range, one can see that the 

 ice must have still filled the valley of the Connecticut both north and south 

 of the Holyoke range, and must have rested with a depth of above 150 feet 

 in the low pass of the Belchertown ponds, so that the stream draining the 

 Pelham basin ran between the point where its bed breaks down suddenly 

 above Dwight's station to where it begins again in Belchertown, with its 

 eastern bank the Belchertown ridge, its bottom and western bank of ice. 



It is clear, finally, that the melting of the ice back across the low 

 western ranges which bounded the lake in Belchertown at last gave this 

 body of water a new way of exit through the course of Broad Brook, which 

 nms down through the middle of these ranges and joins the Chicopee where 

 it turns south in the same longitudinal valley as that of the brook itself, 

 and that the fm-ther retreat of the ice let the waters pass outside (west of) 

 these ranges entirely 



MON XXIX 37 



