610 Systematic Paleoxtology — Upper Devonian 



cave, with a fold in the left valve, a feature not observed in the right 

 valve. There is a shallow undefined depression extending from the umbo 

 to the base, scarcely affecting the margin. Surface marked by fine con- 

 centric striae, which becomes fasciculate on the posterior end of the shell." 

 Hall, 1885. 



The specimens, while poorly preserved, have the characteristics of the 

 Xew York species with sufficient distinctness to render their identifica- 

 tion very probably correct. The species has been observed only in the 

 upper ferruginous beds of the Chemung. 



Length 21-32 mm.; height 9-10 mm. 



Occurrence — Jennings Formation, Chemung Member. Town 

 Creek, 4596 abundant; 2 miles west of Pawpaw, West Virginia, 4694. 



Collection. — ]\Iaryland Geological Survey. 



Genus SPHENOTUS Hall 



Sphenotus contractus Hall 

 Plate LIX, Figs. 18, 19 



Cypricardia contracta Hall, 1843, Geo), of N. Y., Rept. on the 4th Dist., p. 



292, pi. cxxxix, fig. 4. 

 Sphenotus contractus Hall, 1885, Pal. of N. Y., vol. v, pt. i, p. 399, pi. Ixvi, 



figs. 1, 3-9, 11-13, 15; pi. xciv, fig. 2. 



Description. — Shell elongate-trapezoidal, wider behind; lengih more 

 than twice the height; basal margin nearly straight, faintly constricted 

 in the middle. Posterior extremity oblique, rendered somewhat doubly 

 truncate by the ridge on the posterior slope. Cardinal line straight, long, 

 nearly parallel to the basal margin. Anterior end short, abruptly de- 

 clining from the beak and narrowly rounded below. Valves equally con- 

 vex. Umbonal slope angular and extending to the jiostlateral extremity. 

 Surface with fine concentric strife. 



Length 35 mm. ; height 13 mm. 



Occurrence. — Jennings Formation, Chemung Member. On National 

 Eoad, 1 mile west of Sideling Creek; near top of Green Eidge; IV. miles 

 west of Corriganville and near contact with Hampshire formation 1 mile 

 east of Barrelville. Northeast edge of Deer Park. 



Collection. — ]\Inryl;ind Geological Survey. 



