278 



surfaces variously ornamented. Aperture sub-quadrate to 

 sub-orbicular, the inner lip thin. The outer lip bears a nar- 

 row, deep fissure, or sinus, which is the still unclosed con- 

 tinuation of a revolving band. 



Pleurotomaria lucina. Hall. (Fig. 207.) (Pal. N. Y., 

 Vol. Y.. Pt. II., p. 67, PI. XVIII.) 



Distinguishing Characters. — Large size; sub-globose, or 

 obliquely ovoid conical form; moderately elevated spire, 



with minute apex, and 

 about four volutions; 

 regularly and r a p i d 1 y 

 exp anding bo d v -who rl ; 

 expanded, nearly round, 

 apertures, with shallow 

 notch ; neatly defined, 

 sliuhtlv canaliculate su- 

 ture; moderately wide 

 revolving band, limited 

 by revolving ridges on 

 either side ; revolving 

 stria', cancellated by concentric stria? of similar strength. 



Found in the Encrinal limestone, at Section 5 ( verv 

 rare I. 



Pleurotomaria lucina, var. perfasciata, Hall, is dis- 

 tinguished by its coarser fasciculate stria? on the body-whorl, 

 which give the shell a nodose appearance. 



Found in the middle Pleurodictyum bed, in Averv's Ravine 

 (one specimen ). 



Pleurotomaria itys. Hall. (Fig. 208.) (Pal. X. V.. 

 Vol. V.. Pt. II., p. 76, PI. XX.) 



s&tk. Distinguishing Characters. — Turbi- 



nate form, with ascending spire, higher 

 than wide; four or five volutions, grad- 

 ually expanding to the ventricose body- 

 whorl ; broadly oval aperture, some- 

 what higher than wide; strong revolv- 

 er BaST ing stria-, crossed and cancellated by 





Fig. 207. Pleurotomaria lucina. View of a per- 

 fect specimen from the Onondatra limestone of 

 Clarence Hollow : the specimens f r >m the Hamilton 

 group are commonly much distorted (after Hall;. 



