18 Geology., fyc. of the Connecticut. 



once closed up nearly to the generallevel of the neighbour- 

 ing mountains, it must have thrown back the waters of the 

 Connecticut over the whole of the secondary tract marked 

 on the map, with the exception of some of the highest 

 ridges and peaks of greenstone and sandstone, which thea 

 probably formed islands in this extensive expanse of wa- 

 ters. 



At the outlet of the Connecticut through the mountains 

 below Middletown, a little south of the Chatham cobalt 

 mine, and six or seven hundred feet above the present bed 

 of the river, I saw rounded masses of old red sandstone, 

 several inches in diameter, mixed with the fragments of the 

 rocks in place. Such a fact I never noticed at any other 

 place in the primitive region along the river : certainly not 

 on the east side of it. And I was led irresistibly to the con- 

 clusion, that they were conveyed thither by the ice of the 

 ancient lake, which would be floated to the ocean through 

 this outlet. 



In the northern part of the tract supposed to have been 

 covered by this lake, other evidences of its existence pre- 

 sent themselves. In the southern part of Deerfield, the 

 sandstone cliffs of Sugar Loaf, four hundred feet above 

 the present level of the Connecticut, bear evident marks of 

 having been worn and undermined by water : — that is, they 

 appear very much like similar rocks which now form the 

 beds and banks of the Deerfield and Connecticut rivers. Is 

 the north part of Deerfield, at the west foot of the green- 

 stone ridge, and two hundred feet at least above the Con- 

 necticut, is the channel of a stream ten or twelve rods wide, 

 that once ran southerly^ as appears from the little eminences 

 of greenstone that were exposed to its action, which pre- 

 sent a perpendicular front on the north side, while the south 

 side is sloping and presents an accumulation of broken 

 pieces of ihe rock. One mile west from this spot, and a 

 few rods south of the village of Greenfield, appears the 

 bed of a smaller stream which there formed a cataract,* of a 

 few feet over a ledge of red sandstone rocks. In this rock 

 are numerous spheroidal excavations of two or three feet ia 

 depth, leaving no doubt that a current of water once flow- 

 ed there. This channel is less than one hundred feet above 



•* See Dii'kiuscn's View of Massachusetts, p. 33. 



