GLACIAL DRIFT. 215 
The phenomena agree best with the theory that the south-east course 
originally covered both the valley and the adjacent borders for scores of 
miles, but that, after the ice ceased to be furnished abundantly from the 
St. Lawrence, the residue followed its natural way down the several river 
depressions to the sea, and, being of considerable thickness, was able to 
leave abundant evidences of its passage. 
Prof, J. D. Dana was the first to insist upon the existence of a Con- 
necticut glacier separate from the general mass of drift. My father was 
the first of American geologists to point out the fact in any publication 
of the existence of local glaciers radiating from high ridges.* He was 
led to this conclusion from a comparison of the ancient glacial drift in 
Wales and Switzerland with the drift generally, and with the local exam- 
ples seen by him in western Massachusetts and Vermont. As the 
common phenomena of the drift seemed to him best explicable upon the 
iceberg theory, his ready recognition of the real glacial markings in the 
Westfield and Deerfield River valleys shows how ready he was to accept 
truth, even against his judgment of the proper interpretation of the 
phenomena of nature. His suggestion of a movement down the Con- 
necticut valley is not to be regarded as a claim that he understood the 
whole depression to be scored like the few examples he had seen.t The 
fact established clearly by him was, that the Hoosac and Green Moun- 
tains supported the mer de glace in the last part of the ice period, from 
which local glaciers flowed down, both towards the Connecticut on the 
east, and to the Champlain valley on the west. We can now extend this 
deduction eastwardly, and say that there was a Connecticut Valley gla- 
cier in the latter part of the ice period, with branches both from the 
west and the east. 
The branch glaciers on the west that have been described are these: 
Upon Westfield river, with its tributaries, especially Little river ; Deer- 
field river, both in Massachusetts and Vermont; West river, joining the 
* Report Geology of Massachusetts, 1853. Smithsonian Contributions, vol. ix. 
+ The following is the passage referred to (Smithsonian Contributions, vol. ix, p. 136): On examination, I did 
find, on the west side of the Connecticut valley, that what I called drift striz, instead of running north and aide 
as they usually do, turn southerly south of South Hampton as much, in some places, as S. 65° W. I Saspected 
at first, either that these markings were produced by the [Westfield] glacier, after it reached the Connecticut val- 
ley, or that the supposed glacier scratches were the result of drift agency operating up hill. But when I found 
that the stoss of the glacier striz was the west side, and that of the drift strize was the north-east, both these su 
positions were shown to be untenable ; aud I accounted for the south-west direction of the drift striz by he 
expansion to the right of the Connecticut valley south of South Hampton. I think this the ri i 
i e right i 
of the facts, but I could wish to give them further examination. i i 
