14 A Contribution to the Lower Devonian Faunas of Maryland 



MOLLUSCA 



Class PELECYPODA 



Order PRIONODESMACEA 

 Section SCHIZODONTA 



Superfamily PTERINACEA 

 Family PTERINEIDAE 



Genus PTERINEA Goldluss 



Pterinea halli Clarke 



Plate LXXVIII, Figs. 11, 12 



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



liii, figs. 11-14, 1861. 

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



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

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

 the width, moderately convex in the middle and on the umbo: anterior 

 margin long, slightly concave above and curving to the base; posterior 

 margin below the sinus, somewhat abruptly curving into the broad rounded 

 basal margin: anterior wing small, trigonal, subacute, distinctly sepa- 

 rated by a sinus from the body of the shell ; posterior wings large, subacute 

 at the extremity, not strongly distinct from the body of the shell, extend- 

 ing as far as, or a little beyond, the margin of the shell; marginal sinuosity 

 long and shallow. Surface marked by moderately strong radiating cost* 

 and strong elevated concentric striae." Hall, 1859. 



To this species is referred a fragment which has the sculpture and out- 

 line, as far as this latter can be made out, of Hall's species. It is freely 

 admitted that such reference is a mere conjecture. 



Occurrence. — Oriskany Formation, EiDCiELY Member. Cumberland. 



CoUection.—GeoT^e M. Boeder. 



