220 J. Hall on the Primordial Fauna, 
series of that region, and rests unconformably upon the lower 
copper-bearing series, which is the Huronian system. The upper 
copper-bearing series holds nearly all the metals, including gold, 
and so does the Quebec group, each making an important metal- 
iferous region. Hach when unmetamorphosed holds a_ vast 
collection of red colored strata. The want. of fossils in the Lake 
Superior group makes it difficult to draw lines of division, but 
if any part represents the primordial zone, I should hazard the 
conjecture that it is the dark colored slates of Kamanistiquia, 
which underlie all the red rocks. 
Professor Emmons has long maintained, on evidence that has 
been much disputed, that rocks in Vermont, which in June, 
wm 
Mr. Joachim Barrande, Rue Meziére No. 6, Paris. 
IV. 
LETTER FROM JAMES HALL, PALAONTOLOGIST OF NEW YORK, TO THE 
EDITORS OF THE AMERICAN JOURNAL OF SCIENCE AND ARTS. 
Gentlemen,—In the Twelfth Annual Report of the Regents of 
the University* upon the State Cabinet of Natural History, 1 
age of the Hudson River group. These trilobites had been ™ 
my possession for some two years or more; and knowing the 
great interest that would attach to them, whenever published, 
had waited, hoping that some new facts might be brought out 
eyed the stratigraphical relations of these rocks in the tow? 
of Georgia. . . : 
After the descriptions had been printed and a few copies dis 
tributed, I learned that Sir William Logan was at that tim@ 
* The same to which Mr. Barrande refers in his text to Prof. Bronn, p- 312. Bic 4 
preceding communications sufficiently explain the subject under discussioM. 
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