184 SYSTEMATIC PALEONTOLOGY 



cate lines of growth and fine radial rows of minute granules^ obsolete 

 over ninch of the surface; teeth consisting of two small cardinal and 

 one long posterior lateral; pallial line with shallow sinus." Clark, 1896. 



Only two specimens, both right valves, have been found. The one 

 here newly figured is smaller than the type, but more nearly perfect. 

 The teeth are not well preserved, but the radiating rows of granules 

 show the generic affinities. ; 



Length, 20 mm.; height, 16 mm. 



Occurrence. — Aquia Foemation. 1 mile southeast of Mason Springs, 

 Pomonkey Neck. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



Order ANOMALODESMACEA. 



Family PERIPLOMIDAE. 



Genus PERIPLOMA Schumacher. 

 Pekiploma (?) sp. 

 Two specimens have been found which have the general form of this 

 genus, but are too imperfect for complete identification or description. 

 Length, 29 mm.; height, 24 mm. 



Occurrence. — ^Nanjemoy Fokmation. East of Port Tobacco, Wood- 

 stock. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences (No. 6430). 



Family PHOLADOMYIDAE. 



Genus PHOLADOMYA Sowerby. 



Pholadomya maeylandica Conrad. 



Plate XLIII, Fig. 3. 



Tholadomya marylandica Conrad, 1842, Proc. Nat. Inst. Bull, ii, p. 193, pi. i, flo-. o. 

 Pholadomya marylandica Conrad, 1846, Amer. Jour. Sci., ser. ii, vol. i, p. 214, 



pi. ii, fig. 9. 

 Pholadomya marylandica H. C. Lea, 1848, Proc. Acad. Nat. Sci. Pliila., vol. iv, p. 104. 

 Pholadomya marylandica Conrad, 1865, Amer. Jour. Conch., vol. i, p. 3. 

 Pholadomya marylandica Conrad, 1866, Smith. Misc. Coll. (200), p. 8. 

 Pholadomya marylandica Clark, 189.5, Johns Hopkins Univ. Circ, vol. xv, p. .5. 

 Pholadomya marylandica Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 75, pi. xxix,. 



tig. 2. 



