G54 Systematic Paleontology — Upper Devonian 



Cypkicardella marylandica n. sp. 

 Plate LXY, Figs. 11-15 



Description. — Shell considerably larger than C. nitidula, subcircular 

 or somewhat obliqueh' ovate. Beaks anterior; hinge-line gently convex; 

 posterior margin slightly extended and narrowed, rounding somewhat 

 abruptly to the broadly and regularly curved base. The anterior margin 

 is short and inflected beneath the beak, curving outward to the anterior 

 extremity of the shell which lies near the middle transverse axis. Beak 

 depressed ; umbo full, regularly convex, surface falling away equally to all 

 margins except toward the hinge where the convexity is carried farther. 

 Paint trace of a depression on the cardinal slope. Surface marked by 

 regular concentric elevated lines which are at times bunched together in 

 groups or festoons with depressed intervals. 



This shell has much the aspect of some well-known forms of Nucula 

 but though no single specimen displays the hinge in condition for illus- 

 tration, it is evident from certain impressions that the cardinal struc- 

 ture is that of Cypricardella. It differs distinctly in form and contour 

 from any New York species of the genus and approaches most closely its 

 associate C. nitid-ula from which it may be distinguished by its obliquely 

 ovate form and prevailing larger size. 



Length 16 mm. ; height 15 mm. 



The individuals occurring in the upper ferruginous beds of the Che- 

 mung are small and depauperate though they seem referable to this species 

 in other respects. 



Occurrence. — Jennings Formation, Chemung Member. Near Deer 

 Park; National Eoad west of Frostburg; Oakland-Altamont Eoad; Town 

 Creek 2496, 3969, 4631. 



ColJcriion. — Maryland Geological Survey. 



Cyphicardella gregaria (Hall) 



Plate LXV, Figs. 16-18 



Microdon gregarius Hall, 1870, Prelim. Notice Lamellibr., pt. ii, p. 32. 

 Microdon (Cypricardella) gregarius Hall, 1884, Pal. of N. Y., vol. v, pt. 1, 

 p. 309, pi. Ixxiii, figs. 1-6; pi. Ixxxiv, figs. 1-4. 



