Perry.] 52 [February 28, 
denudation has been a very prominent agency concerned in its form- 
ation. If any one doubt this, let him scrutinize the evidence which 
he will everywhere encounter, as he advances from Long Island 
Sound to the Connecticut Lake. Then, too, at times so late as the 
Permian or the Triassic, probably the older rocks, now forming con- 
siderable portions of the bottom of this valley, were generally to a 
considerable extent solidified ; they were perhaps to such a degree 
hardened as not to bend readily, like plastic material, but rather, 
after somewhat of yielding, to break like a pipe-stem, or any other 
form of baked clay. It is not, moreover, so clear as the language 
used seems to imply, that the Paleozoic age witnessed “ the forma- 
tion of the Connecticut River Valley.” While a beginning was 
certainly made in Paleozoic times, the greater part of the work was 
no doubt accomplished at a far later day.t Again, it is not so eyv- 
dent as the author seems to suppose, that the formation of this val- 
ley actually “took place as a sequel to, or in connection with, the 
crystallization of the granite, gneiss, crystalline schists, and other 
similar rocks, which make the bottom of the valley.”? That the 
rocks referred to received their crystalline structure at so late a day 
is a point which, so far as appears, is simply assumed; a point, in 
confirmation of which I have thus far failed to find any adequate 
evidence; a point, therefore, which seems to need a thorough re- 
investigation, and in respect to which I hope at some future time to 
offer a series of facts accompanied by germane suggestions, pointing 
in an entirely different direction. 
According to Professor Dana, “the first fact of the succeeding age 
[comprising the Triassic, the Jurassic and the Cretaceous], of which 
there is record, is the existence of a Connecticut valley estuary, 
twenty miles or more wide, stretching from New Haven to northern 
Massachusetts, . . . and the commencing deposition in this estu- 
ary of the Red Sandstone formation. The production of this forma- 
tion is believed to have taken the whole of the Triassic period, . .- 
1 Since the above was written, Professor Agassiz, while in conversation on 
this point, said to me. ‘‘I have come to the same conclusion. The Connecticut 
valley is very recent, Post-Tertiary.’’ On his return from a sojourn in the yal- 
ley of the Connecticut and among the White Mountains, where he passed the 
last summer, he in substance added: I have now found evidence that geologists 
have scarcely begun to appreciate the work of denudation effected during the 
Glacial period. 
2 Paper cited, p. 46. 
