222 REPORT ON THE AMERICAN COMMITTEE. 
knobs that rise irregularly in the midst of the " Hudson-Trenton '* 
terrane {Agricidture of Neio York, p. 86). More than this, the 
central and principal body of these mountains has not been ex- 
amined at all — that portion lying in the eastern jmrtof Columbia 
County, N. Y. Again, it is a striking agreement with Dr. 
Emmons's description, restrictiLg the range to a single ridge, ac- 
cording to Mr. Walcott's idea, that the first fauna rocks '•' lie aloyig 
both sides" of that ridge. 
Place in juxtaposition with the foregoing the following state- 
ment of Mr. Walcott (p. 242). " Fossils occur more or less 
abundantly at over one hundred localities as now known to me, 
within the typical Taconic area, and they are distributed at vari- 
ous horizons throughout the 14,000 feet or more of strata referred 
to this terrane.^' That is, primordial fossils are found in over 
one hundred localities in the typical Taconic area, in some of the 
strata of the Taconic system of Dr. Emmons, in a terrane that is 
sub-Potsdam. 
Second Proposition. These facts were known to Mr. Walcott 
prior to November, 1887, as fully as since. 
These minor errors in the method of investigation did not 
affect the correctness of the main result, a result the priority of 
which was approved by Messrs, Billings and Barrande, and ac- 
credited by them to Mr. Emmons. Dr. Emmons also repre- 
sented, as further proof of the unconformity of the Taconic rocks 
with the Champlain, that the blue limestone (Mr. Walcott's 
Trenton-Hudson terrane) is unconformable upon the Taconic, 
and this unconformity Mr. Walcott seems to have accounted 
for by an assumed " faulting in between the Taconic," the fault- 
planes being " inclined to horizontal " (p. 400, Am. J. S., May, 
1888). 
Third Proposition. This argument was as patent to Mr. Wal- 
cott prior to November, 1887, as since. 
On the other hand, Dr. Euimons did call attention to the fact 
that these primordial fossils were unlike any in the Champlain 
division, and, as it was not possible they could be more recent, 
he inferred, both paleontologically and structurally, that they 
belonged below the Potsdam. He distinctly states that he regards 
the black slate as the uppermost member of the Taconic. At 
that date there had been no publication of " a clearly defined geo- 
logic section," containing the primordial fauna. 
