MAHYLANI) (I IIOI.OC IC A L sntVKY 187 



Family ANOMIIDAE. 



(iciuis ANOMIA Miillcr. 



Anomia marylandica n. sp. 

 Plato XIJV, Fi<rs. 2, 2a, 3. 



Di'scriplioii. — Slu'll small, lliiii, ii'ccgular; valves very uiiCMiiial; I'iglit 

 valvi' iiMxK'vatcly and uiiiroriuly convex; byssal opening small; left valve 

 very (.•oincx and in'i'>j,'u]ar. Ik'ak anteriorly situated and much in- 

 luivcd. Surface marked by tine raised radiating threads and irregular 

 wavy concentric undulations. Lines of growth strong, irregular. 



Length, 19.5 mm.; height, 18 mm. 



Occurrence. — Nanjemoy Formatiox. Woodstock, Popes Creek. 

 Aquia Formation. Clifton Beach. 



Collection. — Maryland Geological Survey. 



Anomia mcGeei Clark. 

 Plate XLIY, Figs. 1, la. 



(?) Atiomia ruffini Conrad, 1835, Fossils Medial Tertiarj', p. 74, pi. xlii, fig. 6. 



Ano7nia mcgeei Clark, 1895, Johns Hopkins Univ. Circ, vol. xv, p. 5. 



Anomia mcgeei Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 86, pi. xxxiv, figs. 



5«, 5b. 

 in Anomia ruffini Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 93. 

 Anomia ruffini Dall, 1898, Trans. Wagner Free Inst. Sci., vol. iii, pt. iv, p. 782. 



(In part). 



Description. — "Shell of left valve rather solid, convex, nearly equi- 

 lateral; surface strongly lamellar, with faint radial plaits, stronger in 

 the latter than in the earlier portions of the shell." Clark, 1896. 



The type of this species, which is the only adult specimen known, was 

 found in the collections of the Philadelphia Academy of Xatural 

 Sciences labelled "Eocene of Hanover County, Va." Anomia ruffini 

 Conrad was described Avith Miocene fossils (the type having been found 

 on the Pamunkey Eiver, Virginia, where both Eocene and Miocene 

 strata occur), and, was later, by Conrad and by others, placed in lists of 

 both Eocene and Miocene forms. It is extremely doubtful if the species 

 has ever been found in the Eocene. 



The resemblance between A. mcgeei and A. ruffini is so close and 

 both are so different from any other forms which have ever been found 



