Marcou.] 
56 
[Nov. 7, 
The printing had reached p. 224, when Barrande and Marcou’s 
paper was issued. An alteration was an absolute necessity, and 
although the “Quebec group” was allowed to follow the “Utica apd 
Hudson formation” and consequently above it, as it has always 
been placed by Logan, he explains the new position which he in- 
tends to give to that group in the following words : “although from 
their geographical position apparently superior to the Hudson river 
formation, these rocks belong in reality to an older group, which is 
developed to a great extent in eastern Canada, and presents some- 
what different characters in the various parts of its distribution. 
The rocks of this series are still under examination, and the de- 
scriptions now given may hereafter require to be somewhat modi- 
fied” (Geology of Canada, p. 225, 1863). 
So in the volume, the Quebec group is placed above the Lorraine 
shales (Hudson river group) and directly below the Oneida and 
Medina sandstone (called Anticosti group by Logan). In the in- 
troduction on p. 20 (which has been reprinted with alterations), 
the Quebec group in the geological nomenclature, is placed between 
the Potsdam and the Birdseye formation, as the equivalent of the 
Calciferous and Chazy, a transfer passing over the whole Cham- 
plain system, forced upon the geological survey of Canada by the 
publication of J. Barrande and J. Marcou’s paper. Here is the 
classification of the Geology of Canada in 1863. 
FORMATIONS. SYSTEMS. 
Guelph formation 1 
Niagara “ I 
Clinton “ [ Anticosti group, f Middle Silurian. 
Medina “ ' 
Hudson river formation 
Utica “ 
Trenton “ 
Birdseye and Black river formation 
Chazy=Sillery ? “ } Quebec 
Calciferous=L§vis “ ) group. 
Potsdam group : 
Huronian series 
On the “geological map of Canada, 1864, atlas,” we have the Que- 
bec group as the equivalent of the Calciferous and Chazy, marked by 
the same colors, only the number 5 used for the Calciferous is re- 
placed in some cases by 5a. The Chazy is colored yellow with the 
v. Lower Silurian. 
J 
. Azoic. 
