278 



surfaces variously ornameuted. Aperture sub-(|uadrate to 

 sub-orbicular, the iuner lip tliiu. The outer lip bears a nar- 

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

 tinuation of a revolving- band. 



Pleukotomaria Lucix.A.. Hall. (Fig. 207.) (Pnl. N. Y., 

 Vol. v., Pt. II., p. 67, PI. XVlll. ) 



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

 obliquely ovoid conical form ; moderately elevated spire, 



with minute apex, and 

 a b o u t four volutions ; 

 regularly and r a p i d 1 y 

 expanding body-whorl ; 

 expanded, nearly round, 

 a]iertures. with shallow 

 notch: neatly defined, 

 slightly canaliculate su- 

 ture ; moderately w i d e 

 „ .,,. ,„ , 1 ^^ , revolving band, limited 



Fig. 20i. l'li_ ii,"t<iiiiari(i iiicina. \ lew of a ptr- '^ ' 



feet specimen from tlie Onondaga limestone of 1 .-t^ TA\'r>lA'nno' TTr1o'P».j iw\ 



Clarence Hollow : the specimens fr .m the Hamilton ^'} n? \ ui v iijj_, i n.i^cr5 i Jii 



group are commonly much distorted (after Hall;. pifTipv si dp • T e V O 1 V i 11 2" 



striae, cancellated by concentric strite of similar strength. 



Found ill the Encrinal limestone, at Section 5 (very 

 rare). 



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

 tinguished by its coarser fasciculate stride on the body -whorl, 

 which give the shell a nodose appearance. 



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

 (one specimen ). 



Pleckotomaria itvs. Hall. (Fig. 208.) (Pal. X. Y., 

 Yol. v., Pt. n.,p. 76, PL XX.) 



,j^ Distinguisldnu, Cliaracters. — 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- 

 i J/fafter HanT'°'""''''* ing stricV, crossed and cancelhited by 



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