Isocardia Fraterna

Isocardia Fraterna, Say, Jour Acad. Nat. Sc. vol 4 p 143 pl 11 fig 1 [& 2]

Cordate-globose, slightly oblique, with rather large concentric wrinkles, & lines of growth; an elevated undulation on the anterior submargin; umbones not very prominent; apex rather suddenly incurved, acute; impressed space behind the beaks dilated & rather profound; anterior tooth striated, externally, & placed in the middle of the anterior margin.

L. 3.5 B 3.4

Tertiary
Maryland.