560 Systematic Paleontology — Upper Devoniax 



SCHUCHERTELLA ELLIPTICA n. Sp. 



Plate L, Fig. 4 



Descnption. — Shell large, subelliptical. Ventral valve low convex, 

 greatest convexity slightly posterior to middle; cardinal angles rounded. 

 Dorsal valve not observed. Hinge-line straight, area triangular. Surface 

 with numerous rounded striaj which are intersected by faint concentric 

 striaj. Interior of ventral valve has two deep, divergent, fiabelliform 

 muscular scars and shows faint radiating striae which are especially well 

 preserved toward margins. 



Length 30 mm. ; width 48 mm. 



This species differs from S. chemungensis in its rounded cardinal 

 angles and unusually large fiabelliform muscular scars. It is perhaps a 

 very variant form of that species. 



Occurrence. — Jennings Formation, Chemung Member. Town 

 Creek, 4631. 



Collection. — Maryland Geological Survey. 



Schuchertella ? ponderosa n. s]x 

 Plate L, Fig. 5 



Description. — Shell large, semiovate, transverse, length about seven- 

 eighths of width. Ventral valve convex, point of greatest convexity near 

 umbo, anterior margin rounded, center depressed to form a broad, shal- 

 low, scarcely defined sinus. Umbo elevated, projecting beyond hinge-line. 

 Shell thick. Dorsal valve unknown. Area triangular, inclined towards 

 front, about 7 mm. high. Surface not known. Cast of interior of 

 ventral valve shows large fiabelliform scars for attachment of the diduc- 

 tor muscles, separated by small elliptical scars for attachment of adductor 

 muscles. Diductors limited by a low, broad elevation, seen as a semi- 

 circular depression in cast. Surface of cast with irregular elevations due 

 probably to imperfections in shell. 



The cast of the interior of a single ventral valve distorted by pressure 

 has been observed. Its features indicate that it is probably a Schuchertella 

 although its generic relations are insecure. 



