18  — = Geology, &c. of the Connecticut. 
once closed up nearly to the general level 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 then 
probably formed islands in this extensive expanse of wa- 
ers. 
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. Sucha 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 
ar very much like similar rocks which now form the 
beds and banks of the Deerfield and Connecticut rivers. In 
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 the rock. One mile west from this spot, anda 
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 in 
depth, leaving no doubt that a current of water once flow- 
edthere. This channel isless than one hundred feet above 
* See Dickinson's View of Massachusetts, p. 33. 
