PALEONTOLOGY OF NEW-YORK. 
Under other conditions, the plications are more numerous and rounded, the 
squamose imbricating lines less conspicuous, and the shell takes a more orbicu¬ 
lar form, approaching to the L. flabellites ; but the beak is never so strongly 
incurved as in that species. It may be doubtful whether an examination of a large 
number of specimens will sustain a separation from L. {A.) flabellites ; but while a 
considerable number of individuals from two or three localities sustain the charac¬ 
ters originally given, I shall retain it under a distinct specific name. 
Geological formation and localities. This species occurs in the Upper Helder-* 
berg limestone, near Waterville and at Cassville, Oneida county ; at “ Dry-lots,” 
Herkimer county ; at Jamesville, Onondaga county, and at East-Victor, Ontario 
county. Specimens from the same horizon at Waterloo in Seneca county have a 
more orbicular form, with more numerous and less angular plications. 
With our present knowledge of the characters of the Genus Lbptoccelia, the 
L. flabellites, L. fimbriata and L. acutijglicata will remain as typical forms of the 
genus, while Lejptocoelia concava, and L. dichotoma (Pal. New-York, Vol. iii, pp. 245 
'and 452) must be referred to the Genus Coelospira ; to which may be added the 
L. (Atrypa) disparilis of the Niagara group. 
The species Leptoccelia {Atrypa) hemisphetdca (Pal. New-York, Vol. n, pa. 74, 
pi. xxiii, f. 10) and L. {A.) planoconvexa (Ibid. pa. 75, pi. xxiii, f. 11 ; and Vol. hi, 
pi. ciii b, f. 4 and 5) are apparently true Leptoccelia, both from external form 
and from what we know of their internal structure. I nevertheless regard it as 
desirable to make critical examinations of the Clinton group species, in the hope 
of arriving at a more satisfactory knowledge of their internal structure and 
relations. 
