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PALAEONTOLOGY OF NEW YORE. 
Hndson-river group; also the genus Endoceras, embracing the following 
species: E. gemelliparum and E. subcentrale, from the Black-river limestone; 
E. longissimum and E. multitubulatum, from the Black-river and Trenton lime¬ 
stones; E. angusticameratum, E. annulatum, E. approximatum, E. arctiventrum, E. 
distans, E. duplication, E. magniventrum, E. proteiforme var. elongatum, E. protei- 
forme var. lineolatum, E. prof. var. strangulatum, E. prot. var. tenuistriatum and 
E. prot. var. tenuitextum, from the Trenton limestone; E proteiforme, from the 
Trenton and Hudson river groups; also, Gonioceras anceps, from the Black-river 
limestone {Palaeontology of New York, vol. 1). 
In 1850 Mr. Hall described Endoceras lativentrum and Ormoceras remotiseptum, 
from the Trenton limestone; and Colpoceras virgatum [= Endoceras virgatum\, 
from near the junction of the Birdseye and Black-river limestones. 
In 1851 Mr. Hall described Huronia annulata, from the Niagara group {Report 
on Lake Superior Land District: Foster & Whitney. 
In 1852 Mr. Hall described Orthoceras abruptum [= Cyrtoceras?] and 0. multi¬ 
septum, from the Medina sandstone ; 0. virgulatum, from the Clinton and Niagara 
groups; and 0. cancellatum [= 0. subcancellatum, H., 1877]; and identified O. 
imbricatum, Waiil., 0. annulatum? Sow., 0 . undulatum* His., and O. virgatum? 
Sow., from the Niagara group; Ormoceras vertebr.atum and Discosorus conoideus, 
from the Clinton group {Palaeontology of New York , vol. 2). 
In 1857 Mr. E. Billings published the following species : Orthoceras cornuum, 
from the Chazy group; 0. Allumettense and 0. Minganense, from the Chazy and 
Black-river groups; 0. decrescens, 0. hastatum, 0. Murrayi and O. Ottawaense, from 
the Black-river and Trenton groups; 0. Huronense, O. Python, O. vulgatum and 
0. Xiphias, from the Trenton group; 0. Anticostiense, 0. balteatum, 0. Lyelli, 0. 
magnisulcatum, 0. propinquum, 0 perannulatum, O. Crocus and O. Sedgwicki, from 
the Hudson-river group; 0. formosum, from the Trenton, Hudson-river and 
Anticosti groups; 0. rotulatum, from the Niagara group; 0. persiphonatum and 
0. Canadense ( — Huronia vertebralis, Stokes, 1823), from the Middle Silurian; 
and 0. Bucklandi, from the Upper Silurian {Rep. of Progr. Geol. Survey of Canada 
for 1857). 
* The species 0. annulatum and 0. undulatum are identical, the former having- precedence in time. 
