Maryland Geological Survey 357 



Family CONOCARDIIDAE 



Genus CONOCARDIUM Bronn 

 CONOCARDIUM NORMALE Hall 



Plate XXX, Figs. 1-2 



Conocardium normale Hall, 1883, Pal. N. Y., vol. v, pt. i, pi. 68, figs. 17-19. 

 Conocardium normale Hall, 1885, Pal. N. Y., vol. v, pt. i, 2, p. 411, pi. Ixviii, 

 figs. 17-19. 



Description. — Shell large, subovate, trigonal ; length about twice the 

 height; basal margin regularly curving. Posterior extremity obliquely 

 truncate. Cardinal line straight. Anterior end narrow, nasute. Valves 

 ventricose, abruptly contracted anteriorly and truncate behind. Beaks 

 posterior to the center, prominent, strongly incurved. Umbonal slope 

 angular, continuing to the post-inferior margin. Post-cardinal slope 

 concave. Test thick, body of the shell marked by numerous radii, between 

 which are undulating lamellose concentric striae. When the shell is 

 exfoliated the radii become stronger and the intermediate surface is 

 marked by fine radiating striae. With the growth of the shell the anterior 

 rays become greatly strengthened and semi-tubular. The cast of the foot- 

 sheath is bilobed, and doubly pointed behind. Two specimens measure 

 respectively 50 and 60 mm. in length, 35 and 32 mm. in height, and 26 

 and 30 mm. in the depth of both valves. This species bears a close re- 

 semblance to the elongate forms of C. cuneus. There is, however, no 

 tendency to a duplication of the ribs, which is a common feature in the 

 specimens from the Schoharie grit. Hall, 1885. 



Occurrence. — Romney Formation, Hamilton Member. Near Cum- 

 berland. 



Collection. — New York State Museum. 



Conocardium cumberlandi^ Swartz n. sp. 

 Plate XXX, Figs. 3, 4 



Description. — Shell small, ovate cuneate; length and height subequal. 

 Valves gibbous in center, very abruptly contracted anteriorly; anterior 

 extremity extended, nasute; truncate posteriorly. Beaks a little behind 

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