Jt'i 



Fro. 197. Plati/ceras 

 bucculentum (after 

 Hall). 



Platvckuas BUCCULEXTI'M. Hall. ( Fig. V.U .] { Pal. X. Y., 

 Vol. v., Pt. II., p. 10, PI. 111.) 



Distinffuishina; Chanictvrs. — I v v e g u I a r 

 form ; closely iiirolled spire, making one 

 or two volutions; rapidlj' and unequally 

 expanding lower portion; rounded longi- 

 tudinal folds or senii-})lications ; faint re- 

 volving striae. 



Found in the Encrinal limestone, at Section ."j (doubt- 

 ful). 



Platyceras SYMMETRicr.M. Hall. (Fig. li)S.) (Pal.X.Y., 

 Vol. v., Pt. Il.,p. 9. PL HI.) 



Dis tinguishing Characters.— 

 Strongly arcuate and incurved 

 form, with one or one nnd one-half 

 A'olutions coiled in the same plane, 

 last volution free; ecpially spi'ead- 

 ing lower portion; oblique, sub- 

 quadrate to rhomboichil aperture; 

 sinuate peristome; concentric 

 strife; and obscure longitudinal 

 ridges. 



Found in the middle Pleurodictyum bed, in Avery's Ci-eek 

 (rare). 



PlATYCEKAS ( OkT1IOXY( UIA ) ATTEXIATUM. 



199.) (Pah N. Y., Vol. V., Pt. H., p. 6, 

 Pl.IH.) 



D is t in g u is h in g Cliaracters. — Conical 

 form ; minute and slightly in rolled apex, 

 making from one to one and one-half volu- 

 tions ; abrupt expansion of body-whorl ; 

 very oblique peristome ; crowded, undulat- fig. iw. piutuceras 

 ing concentric strict; irregular, undefined HaU).""'"'" '^^^'^'' 

 longitudinal folds ; sinuous peristome. 



Found in the Encrinal limestone, and the Stictopora and 

 Demissa beds, at Section 5 ; in the Trilobite beds, at Section 

 8 (rare). 



Fig. 19S. Fltitiicms s,/ii,i,ief- 

 ricHin. A characteristic- s|M-riiiien 

 — the lower part is ti"i sti'im^'ly 

 differentiated from theuiiiJi'ii fioiii 

 Hall). 



Hall. (Fi< 



