450 Systematic Paleontology 



MOLLUSCA^ 



Class PELECYPODA 



Order PRONODESM ACEA 

 Section PALAEOCONCHA 



Family GRAMMYSIIDAE 



Genus GRAMMYSIA Verneuil 



Grammysia sp. ? 

 Plate LXXV, Pig. 1 

 Description. — An incomplete individual, evidently belonging to this 

 genus has been found in the Keyscr member. It is the only representative 

 of the genus that has been found in the state. The specimen being broken 

 off just posterior to the beaks prevents determination but it probably is a 

 new species. 



Occurrence. — Helderberg Formation-, Keyser Member. Keyser, 

 West Virginia. 



Collection. — U. S. National Museum. 



[Maynard. 



Section SCHIZODONTA 



Superfamily PTERINACEA 

 Family PTERINEIDAE 



Genus PTERINEA Goldfuss 



Pteeinea halli Clarke 



Plate LXXVIII, Figs. 11, 12 



Avicula securiformis Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 290, pi. 



liii, figs. 11-14, 1861. 

 Pterinea halli Clarke, 1903, Bull. N. Y. State Mus., No. 5, p. 495. 



Description. — " Shell subrhomb ovate, slightly oblique ; length and 

 height varying from nearly equal, to the height one-fourth greater than 



' The authors responsible for the text of the Mollusca are indicated for each 

 species. 



