880 J. D. Dana—Note on the Bernardston Helderberg Formation. 
intervened ap the deposition of the hornblendie stratum 
and quartz 
hile nc dissenting from my conclusions, Professor Hitch- 
cock adopts my suggestion that the garnetiferous mica slate 
which overlies the quartzyte and limestone at the pees 
limestone locality is identical with the Cods slate of the 
necticut Valley in all its characters and age, and hence that of 
the former should turn out after all to be Helderberg, the 
Coés formation (which extends up the valley to Canada, accord- 
ing to Professor Hitchcock) is also Helderberg or later Upper 
Silurian. 
These differences of opinion, and the wide bearing of the 
facts on New —— geology have led me to revisit the place 
and examine it an n my former paper I closed by stating 
my intention, afeither season, to study the stratigraphical 
details of the region, aan trace out the limits or ran . 
formations southward along the Connecticut Valley. But 
other geological work in Westerns and Southern New England, 
and on the islands off its southern coast, have since occupied 
such leisure time as I could command. In my recent visit to 
Bernardston I was accompanied by Professor B. K. Emerson, of 
Amherst College; and it is a great sativfaction to know that he 
will give the whole subject a careful and thorough study, and 
connect it with a general geological survey of Central and 
Western Neauantinests <woek for which he is eminently fitted. 
To facilitate explanations I repeat the section of the strata 
at the Bernardston locality before published, with one correc- 
tion. 0. 8, the blocked area, represents the stratum of 
Crinoidal limestone : Nos. 1 and 4, dotted areas, an underlying 
and an overlying stratum of quartzyte; and "Nos. 2 and 5 
tinely lined areas, an underlying and an overlying stratum of 
SE 
Se = TT 
Older cla; 
garnetiferons mica slate. The succession and BER are the 
me as in the section by Professor Hitchcock in the Vermont 
Geological Report, excepting the omission here of a layer of slate 
papas over the limestone. 
conclusions which the facts coe to me to sustain, in 
Spposition to those set forth by Professor C. H. Hitchcock in 
the New Hampshire Report of 1877, Bae mostly in agreement 
with Mr. C. H. Hitchcoek of the Vermont Report* (p. 598) of 
1861—are the following : 
*The Vermont Report makes no — in the oe én the Bernardston 
limestone (p. 447), of the rei nat S, gnei ss, ete., of the adjoining region 
on the east. But on page 598, in an fas of “Section I,” extending across the 
