498 
PALAEONTOLOGY OF NEW-YORK. 
NOTE upon the Genus Graptolithus, and Descriptions of some remarkable new forms 
from the shales of the Hudson-river group , discovered in the investigations of the 
Geological Survey of Canada , under the direction of Sir W. E. Logan. By James 
HaLL. [ Communicated in April, 1855.] 
The discovery of some remarkable forms of the Genus Graptolithus, during 
the progress of the Canada Geological Survey, has given an opportunity 
of extending our knowledge of these interesting fossil remains. Hitherto 
our observations on the Graptolites have been directed to simple linear 
stipes, or to ramose forms, which, except in branching, or rarely in having 
foliate forms, differ little from the linear stipes. In a few species, as G. 
tenuis (Hall) and one or two other American species, there is an indica¬ 
tion of more complicated structure; but up to the present time, this has 
remained of doubtful significance. The question whether these animals, in 
their living state, were free or attached, is one which has been discussed 
without result; and it would seem to be only in very recent times that 
naturalists have abandoned altogether the opinion that these bodies belong 
to the Cephalopoda. 
In the year 1847, I published a short paper on the Graptolites from 
the rocks of the Hudson-river group in New-York : to the number there 
given, two species have since been added from the shales of the Clinton 
group. Other species, yet unpublished, have been obtained from the 
Hudson-river group ; and since the period of my publication in 1847, large 
accessions have been made to our knowledge of this family of fossils, and 
to the number of species then known. The most important publications 
upon this subject are Les Graptolites de Boheme, par J. Barrande, 1850; 
Synopsis of the Classification of British Roclcs, and Descriptions of Palaeozoic 
Fossils, by Bev. A. Sedgwick and Frederick M‘Coy, 1851; Grauwacken 
Formation in Sachsen, etc., von H. B. Geinitz, 1852. 
The radix-like appendages, known in some of our American as well as 
in some European species, have been regarded as evidence that the animal 
in its living state was fixed; while M. J. Barrande, admitting the force 
of these facts, asserts his belief that other species were free. It does not, 
