2G5 

 Gems PAKACYCLAS. Hall. 



[Ety. : Para, allied to; cyclas, a genus.] 

 (1843: Geol. Surv. N. Y., Report, 4th Dist., p. 171.) 



Shells with equal, nearly equilateral, valves, sub-orbicular 

 or broadly sub-elliptical. The anterior end is regularly 

 rounded, the posterior end rounded or sub-truncate. Small 

 low beaks, short hinge line, concentric stria-, and often con- 

 centric ridges, further characterize this genus. 



Paracyclas lirata. (Conrad.) (Fig. 186.) (Pal. N. Y., 

 Vol. V., Pt, I., p. 441, Pis. LXXIL, 

 XCV.) 



Distinguishing Characters.— Nearly 

 circular outline ; medium size; strong 

 concentric ridges. 



Found in the hard layer of Mar- 

 cellus age, ten feet above the base, 

 at the northern end of Athol Springs Cf g£ H 8 aio Po 

 Cliff (very rare). 



Genus TELLINOPSIS. Hall. 



[Ety. : Resembling a Tellina.] 

 (1880: Preliminary notice Lamellibranchiata, 2, p. 80.) 



Shells with equal, nearly equilateral valves, sub-elliptical 

 in outline. The anterior end is rounded and the posterior 

 end sub-truncate or emarginate. Small beaks, gently curving 

 cardinal line, prominent umbonal slopes, small external 

 ligament, concentric stria?, and radiating stria? (sometimes 

 obsolete), are other characteristic features. 



Tellinopsis sub-emarginata. (Conrad.) (Fig. 187.) 

 (Pal. N. Y., Vol. V., Pt. I., p. 464, PL LXXY1.) 



Distinguishing Characters. — Sub-em arginate posterior end ; 

 large rounded anterior end; oblique depression extending 

 from the beak to the posterior margin, or below ; flattened 

 space, limited on each side by a ridge and extending from 

 the beak to the antero-basal margin ; fine concentric and 

 fine radiating stria?. 



