198 J. D. Dana on the Glacial and 
ArT. XXIV.—On the Glacial and Champlain eras in New 
England ; by JAMES D. Dana. 
Tue following brief statement of some of. the views | 
have been led to entertain, with regard to the Glacial and Cham- 
plain eras in New England, is here presented to close up a 
contributions on the subject and help forward discussion. 1t 
may also serve a good turn by preventing a waste of energy - 
combating misunderstandings, such as occurred not long since. 
Fuller illustrations with regard to most of the topics, supple- 
mentary to those in my Manual of Geology, will be found in 
my Memoir on the Geology of the New Haven Region, in vol- 
ume ii (1870) of the Transactions of the Connecticut Academy, 
and in papers in the volumes of this Journal for 1871. On 
of the Boston Soc. Nat. Hist., vol. xv, p. 48, 1872. The “strict- 
ures” of the author (read before the B. 8. N. H. in 1870) “on Dana’s Geology of the 
New Haven region” are, for the most part, not on my views but on his unfortunate 
misunderstandings of them. In the commencement of his remarks on the Post-ter- 
tiary, he says that Post-p Lyell ponds t Terrace or Recent | ds 
—the third division of the Post-tertiary ; when, in fact, as my Geology shows, it1s 
very closely equivalent of the Glacial and Champlain eras, or the first two divisions. 
In another place he states that the Champlain era seems to have been, in my View, 
one in which the ocean extended over the most of New England beneath 
1: £ 
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glacier, and the deposits made were chiefly marine :—wh P both 
views in my memoir as well as 1 d have made the era that of the most 
extensive freshwater formations in the world’s geological 
marks th fer to the Te era the terrace deposits of the river valleys 
sea-shores ; when, as I make these preéminently the Champlain deposits, 
Terrace era only the terracing of the Cha’ , and the 
fo: some superfi eposits. The ving m y “Terrace oF 
Recent” era to cover a large of the Champlain era, he institutes for the rest— 
a 
¢ part in his view, which he supposes I wrongly annexed to the Terrace 
era—another grand division of the Post-tertiary and provides it with a name; 
which grand division is essentially identical in its deposits with the whole of my 
“ Terrace or Recent” era. is ‘“ comedy of errors” relates to subdivisions which 
are explained at length in my Geology and adopted in the memoir. : 
Other e: of the misunderstandings that pervade the article might be 
mentioned; but these are enough, 
