1872.] 96 [Perry. 
Mountains and these high lands, on their way to Lake Champlain, 
have westerly (and not, as has been affirmed, easterly), striz in _ 
«s 
great abundance. 
In the light of what has been advanced, I am constrained to ques- 
tion another statement of Professor Dana. “In the case of large 
continental valleys,” (the italics are his,) “the glacier followed the 
course of the valley even where this course was east arid west, as is 
shown by the author to have been true of the Mohawk valley.’’+ 
This lancuage is evidently used in regard to the phenomena of the 
Ice period generally, and without any intention of restricting it to’ 
any portion. That what is asserted may have been, to some extent, 
the fact in the lower part of the River St. Lawrence, and thus near 
the Atlantic side of the great ice-sheet, is not denied ; it was perhaps 
actually the case. Indeed, I have found some evidence that, along 
the eastern margin of the ice-region, as in Essex County, Mass., 
(though this instance was perhaps due to another cause), there was, 
as might be naturally expected along the lateral limits of the con- 
tinent, a strong tendency eastward.? This, however, is one thing, 
while the case of the Mohawk valley is quite another. So far as the 
evidence in regard to the latter locality has come to my knowledge, 
the course of the ice-stream, during the Middle Glacial times, was 
southward, and directly across the valley in question. That the ice 
followed the depression now traversed by the Mohawk River, per- 
haps during the opening, and very evidently during the closing por- 
tion of the Glacial period, is of course most cheerfully admitted. 
Another statement may be noticed, not because of its intrinsic im- 
1 Paper cited p. 50. 
2Many, no doubt, in their study of the evidences of the former activity of ice- 
agency in New England, have been surprised that the prevailing direction of the 
striz is so strongly toward the south-east. Since the predominant trend of these 
strie is regarded by some as conclusive evidence of an elevation of the region 
lying to the north-west of New England, from which it is supposed the ice-mass 
descended, a few additional words on this point may bein place. Granting the ex- 
istence, in the northern part of the contineut, of a vast ice-sheet, with a south- 
erly motion, we see at once that other things being equal, the main trend, especially 
in the centre of the continent, would be north-southward. If we grant again, 
that the ice was of great thickness, and that there was an Atlantic basin on the 
east, it is equally evident that the prevailing trend of the mass along the eastern 
margin of the continent would besomewhat toward the southeast. Such would 
be the case, the whole continent remaining at substantially its present height. 
Thus the eastings in New England have a legitimate origin in the conditions that 
no doubt prevailed during the Ice period; they therefore neither prove the 
theory of upheaval, nor require it in order to their natural explanation. 
