648 Systematic Paleontology — Upper Devonian 



■with anterior margin, more nlirupth' at junction witli posterior margin. 

 Beaks subcentral, sligiitly anterior to middle of valve; somewliat elevated, 

 incurved, over hings-line. Valves convex, slightly gibbous near umbo; 

 surface sloping rapidly towards anterior margin, slowly towards posterior 

 and ventral margins. Umbonal angle not distinct. Casts of interior 

 show a bifid tooth in right valve; posterior and anterior muscular scars 

 well marked. 



Length of larger individual 50 mm.^ height 45 mm. 



This species differs from previously described species of Schizodus 

 in its nearly central umbo and almost equilateral triangular outline. It 

 somewhat resembles a shell referred with doubt to S. chamungensis by 

 Hall in the Paleontology of New York, vol. v, part i, section ii, pi. Ixxv, 

 fig. 41 but its umbonal slope is less distinctly angular. An individual 

 illustrated in pi. Ixiv, fig. 18, is questionably referred to this specie.-. Its 

 outline suggests the genus Edmondia. 



Occurrence. — Jennings Formation, CHEiiuNo ]\Iember. Town 

 Creek, 2023, 2238. Parkhe.4^d Member. Williams Poad, on Polish 

 Mountain, 1352; Millstone 1772 ?. 



Collection. — Maryland Geological Survey. 



Superfamily PECTINACEA 



Family PECTINIDAE 



Genus AVICULOPECTEN McCoy 



AviCULOPECTEN cf. CANCELLATUS Hall 



Pecten cancellatus Hall, 1843, Geol. of N. Y., Rept. 4tli Dist., p. 265. 

 Aviculopecten cancellatus Hall, 1884, Pal. of N. Y., vol. v, pt. 1, p. 18, pi. vii, 



figs. 12, 14-19. 



Description. — Shell rather small, oblique-ovate; beak siibcentral. Sur- 

 face covered with fine radial strife alternating in size and crossed by 

 delicate cancellating lines. 



A single valve has been observed which is questionably identified with 

 this species. 



