458 Systematic Paleontology 



Several specimens from the Oriskany of the state are referred to this 

 variety. The close resemblance between A. communis, the typical A. 

 textilis and the varietal form, casts doubt upon the identification of the 

 forms as they occur in Maryland. 



Occurrence. — Okiskany Formatiox, Ridgely Member. Warren 

 Point, Pennsylvania; west side of Queen's Point opposite Keyser, Miller's 

 Spring, West Virginia. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



[Ohern.] 



ACTINOPTERIA VIRGINICA n. Sp. 



Plate LXXVIII, Figs. 1, 2 



Description. — Body of the shell obliquely ovate, gibbous, maximum in- 

 flation about one-third the distance from the beak to the base. From this 

 point the shell arches rapidly to the beak and gently to base; contracts 

 rapidly on either side of the umbo near the beak and less so as the distance 

 from beak increases; beaks not prominent; posterior wing not sharply 

 separated from body, convex; anterior wing not seen; anterior extremity 

 suddenly rounded, basal margin broadly and regularly arcuate, posterior 

 extremity broadly rounded; surface of body covered by low, arched, 

 radiating ribs, between which, toward the margin, finer ones are inter- 

 posed ; posterior wing unornamented. Hinge-line straight. 



The description is from a cast of the interior of a left valve which is 

 not quite complete. The species bears some resemblance to A. recticosta 

 Hall, but the general outline and the character of the radiating ribs at 

 once separate it. Another imperfect cast in the Maryland Geological 

 Survey collection is doubtfully referred to this species. It is, however, 

 more oblique, the large ribs are smaller and the small ones larger in pro- 

 portion than the specimen described. It is not improbable that further 

 collections will separate this as another species, the material now in hand 

 not warranting such procedure. 



Length 6.5 cm. ; height 4.5 cm. 



Occurrence. — Oriskany Formation, Eidgely Member. Near Foun- 

 tain, four miles southwest of Keyser, West Virginia ; Hancock, Maryland. 



Collections. — ^Maryland Geological Survey, U. S. National Museum. 



[Ohern.] 



