MARYLAXD GEOLOGICAL SURVEY 393 



A7'ca virgiHue Dall, 1898, Trans. Wagner Free Inst. Sci., voL v, pt. ii, p. 9, pL i, 



fig. 3. 

 Barhaiia (Granoarca) virginice Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, 



p. 627, pi. xxxii, fig. 23. 



Descripiion. — "Area virginiw is a large, solid, elongated shell, equivalve 

 but very inequilateral, the beaks being situated near the anterior fifth of 

 the length, low and prosogyrate, distant and separated by a wide cardinal 

 area with numerous (nine) slightly angular longitudinal concentric 

 grooves; sculpture of about twenty-five strong radial ribs, smaller on the 

 posterior dorsal area, somewhat flattened, and on the posterior part with 

 a shallow, wide mesial furrow, hinge line \\ as long as the shell ; teeth 

 vertical, in two series, beginning mesially very small, distally larger, and 

 with a tendency to break up or l)ecome irregular; museuhu' impressions 

 deep; margin fluted in harmony with the ends of the ribs. ..." Dall, 

 op. cit., vol. iii, p. 638. 



Two imperfect and much Avorn shells from the St. Mary's River, 48 

 and 34 mm. in length, respectively, probably belong to this species. 



Length, 83 mm. ; height, 52 mm. ; diameter, 42 mm. 



Occurrence. — St. Mary's Formation. St. Mary's Eiver. 



Collections. — Maryland Geological Survey, Wagner Free Institute of 

 Science. 



Subfamily PECTUNCULIN^. 



Genus GLYCYMERIS Da Costx 

 Glycymeris parilis (Conrad). 



Plate CVIT, Figs. 1, 2. 



Pectunculua lentiforiiiix Conrad, 1842, Proc. Nat. Inst., Bull, ii, pp. 181, 183 (listed 



only). 

 Not Pectimcuhis lentifoDids Conrad. 1837, Fossil Shells of the Tertiary, 2nd. Edit., 



p. 36. 

 Pectu7iculus parilis Conrad, 1843, Proc. Acad. Nat. Sci. Phila., vol. i, p. 306. 

 Pectunculus parilis Conrad, 1845, Fossils of the Medial Tertiary, p. 64, pi. xxxvi, 



fig. 2. 

 Pectunculus parilis Conrad, 1863, Proc. Acad. Nat. Sci. Phila., vol. xiv, p. 580. 

 Pectunculus parilis Meek, 1864, Miocene Check List, Smith. Misc. Coll. (183), p. 5. 

 Cnycymeris parilis Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 609. 



Description. — "Orbicular, slightly oblique; height and length equal; 

 posterior superior margin obliquely subtruncated ; ribs defined by slightly 



