218 Systematic Paleontology — Middle Devonian 



cardinal slope; and fine surface sfriae witlioiit the undulations of 0. 

 undulata. 



Length, 10 mm.; height, 3 mm. 



Occurrence. — Eomney Formation, Hamilton Member. East bank 

 Evitts Creek below Wolfe Mill. 



Collections. — Maryland Geological Survey; New York State Museum; 

 American Museum of Natural History. 



Family GRAMMYSIIDAE 



Genus GRAMMYSIA de Vemeuil 



Grammysia bisulcata (Conrad) 



Plate XXII, Fig. 3 



Pterinea bisulcata Conrad, 1838, GeoL Surv. N. Y., An. Rep., p. 116. 

 Cypricardites bisulcata Conrad, 1841, Geol. Surv. N. Y., An. Rep. p. 52. 

 Grammysia Jiamiltonensis de Verneuil, 1847, BuU. Soc. Geol., France, 2d ser., 



tome iv, p. 696. 

 Grammysia bisulcata Hall, 1870, Prelim. Notice Lamellibranchiata 2, p. 49. 

 Grammysia bisulcata Hall, 1885, Pal. N. Y., vol. v, pt. 1, Lamellibranchiata ii, 



p. 359, pi. liv, figs. 1-16; pi. Ivi, fig. 1; pL xciii, fig. 25. 

 Grammysia bisulcata Keyes, 1891, Johns Hopkins Univ. Circ, vol. xi, p. 29. 

 Grammysia bisulcata Clarke, 1903, N. Y. State Mus., Bull. 65, p. 397. 

 Grammysia bisulcata Grabau and Shimer, 1909, N. Am. Index Fossils, vol. i, 



p. 381, fig. 485b. 



Description. — " Shell large, ovoid ; length once and a half the height ; 

 basal margin broadly curved; Avith a constriction near the middle of its 

 length; posterior margin abruptly rounded below and broadly curving 

 or subtruncate above; anterior end abruptly rounded below the deep 

 lunula; cardinal line nearly straight, more than half as long as the shell. 

 Valves regularly convex below and gibbous or ventricose in the middle 

 and above; beaks subanterior, strong, incurved over the cardinal line; 

 umbo prominent, gibbous, with a cincture consisting of a strong fold with 

 a furrow on each side, extending from the beak to the basal margin at 

 about the middle of its length. Surface marked by fine concentric striae, 

 which, on some portions of the shell, are aggregated into fascicles; and by 

 strong persistent concentric ridges or folds, which are stronger upon the 

 anterior part of the shell and distinctly undulated in crossing the 

 cincture." Hall, 1885. 



