HISTORY OF DERRYFIELD. 4/ 



through Ashburnham and Winchendon, Mass., and thence into 

 the Connecticut. The reality of this line of drainage is evi- 

 denced by the extensive knmes and gravel deposits extending 

 from the Contoocook valley through the towns of Rindge and 

 and Winchendon." 



This evidence is as interesting as the facts are remarkable, but 

 that which follows is to us of more absorbing interest, since it 

 reinforces our assumption of a great water-way, fed from the 

 the same sources, and stretching southward immediately west 

 of the Dunbarton ridge and the Uncanoonucks. Our authority 

 continues : 



'• When the ice had withdrawn a little further north, an outlet 

 was open to the southeast into the Souhegan river, and thence 

 into the Merrimack. The evidence here is also conclusive that, 

 for a period, a stream of water eighty feet deep poured through 

 this piss, and the lake formed in front of the ice was in its great- 

 est extent thirty miles long, and from two hundred to two hun- 

 dred and fifty feet in depth. The evidence of this remains in 

 delta terraces at that level formed at various points where 

 streams came into the lake." 



Here, then, we have high testimony to the existence of other 

 ice-fed streams and lakes nearly at our own door, distinctly cor- 

 roborative of the claims heretofore advanced. We are unable 

 to determine whether any portion of the current of this great 

 water-course contributed to swtll the tremendous torrent which 

 rushed down through the gorge of the Devil's Pulpit. It is cer- 

 tain, however, that the outlet of this lateral valley opened into 

 the great Contoocook lake, finally finding its way into the Mer- 

 rimack ; and it is altogether probable that the enormous water- 

 supply required was derived wholly from the glacial sheet which 

 still hung upon the summit and flanks of the Uncanoonucks. 



We are able to add an additional link to the chain of evidence 

 already presented, in the existence of extensive clay-beds at the 

 site of the lake referred to. Before the day of railroads these 

 deposits were extensively worked, as many as twenty million of 



