214 
REPORT OF THE AMERICAN COMMITTEE. 
Kock 
Masses. 
Faunas. 
Lower Held- 
erburg. 
Salina. 
Niagara. 
Silurian, or Third Fauna. 
Sub-faunas, Lower Helderberg, Niagaz'a, Clinton. 
Lorraine. 
Utica. 
Trenton. 
Chazy. 
Cambrian, or Second Fauna. 
Sub-faunas, Lorraine, Utica, Trenton. 
Calciferous. 
Potsdam. 
Taconic. 
St. John's. 
Taconic, or First Fauna. 
Sub-faunas, St. Croix, Taconic, A.cadian. 
With slight exceptions the nomenclature recoramen4ed here- 
with is the same as that offered by Mr. C. D. Walcott, the 
variations from his plan being those which do not pertain to 
any paleontologic questions, but to physical structure and to the 
value of historical evidence. 
These variations consist (1) in the enlargement of the rank 
of the term Taconic, as a faunal term, so that it becomes synony- 
mous with Bari'ande's term pimordial, and (2) the use of the 
term St. Croix as a sub-faunal horizon instead of that of Pots- 
dam. 
In recommending the term Taconic as a faunal horizon in 
place of the term Cambrian, the latter reverts to the position 
where, as a faunal designation, Messrs. Sedgwick and McCoy 
define it, viz., to the second fauna, and the Taconic becomes 
essentially what Dr. Emmons claimed for it, viz., a fauna below 
the Champlain. 
Respectfully submitted, 
N. H. Winch ELL, 
Eeporter on the Lower Paleozoic. 
Minneapolis, March 24th, 1888. 
