350 SYSTEMATIC PALEONTOLOGY 



both are smooth; base arcuate; disk sculptured with rather close-set, 

 regular, subequal, flattish, concentric ridges with narrower interspaces; 

 these are sometimes feebly elevated, but preserve their general close-set, 

 regular character; hinge well developed, the posterior cardinal in the 

 left valve often conspicuous. Height, 3.2, breadth, 3.2, diameter, 1.7 

 mm. 



"This species is especially characterized by the closeness, regularity, 

 and smoothness of its concentric ridges and the long and narrow lunula 

 and escutcheon." Dall, 1903. 



Length, 3.4 mm. ; height, 3.24 mm. ; diameter, 0.75 mm. 



Occurrence. — Choptatstk Formatlon. Greensboro. Calvert Forma- 

 tion. Plum Point (U. S. Nat. Mus.). 



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



Crassatellites (Crassinella) galvestonensis (Harris). 

 Plate XCIV, Figs. 13, 14. 



Eriphyla galvestonensis Harris, 1895, Bull. Amer. Pal., vol. i, p. 90, pi. i, figs. 2, a, b. 

 Crassatellites {Crassinella) galvestonensis Dall, 1903, Trans. Wagner Free Inst. Sci., 

 vol. iii, pt. vi, p. 1478, pi. xlix, flg. 14. 



Description. — '* Form as indicated by the figures ; hinge as in E. lunu- 

 lata; exterior smooth, slightly undulating concentrically near the beaks; 

 beaks, as in many species of Astarte and Crassatella, slightly flattened at 

 the very apex but very gibbous just below." Harris, 1895. 



Length, 7.2 mm.; height, 6. Go mm. 



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



Collection. — Maryland Geological Survey. 



Family ASTARTID/E. 



Genus ASTARTE Sowerby. 



Astakte vicina Say. 



Plate XCIII, Figs. 10, 11. 



Astarte vicina Say, 1824, Jour. Acad. Nat. Sci. Phila., vol. iv, 1st ser., p. 151, pi. ix, 



fig. 6. 

 Astarte vicina Conrad, 1840, Fossils of the Medial Tertiary, p. 41. 

 Astarte exaltata Conrad, 1841, Proc. Acad. Nat. Sci. Phila., vol. i, p. 29. 

 Astarte exaltata Conrad, 1843, Jour. Acad. Nat. Sci. Phila., vol. viii, 1st ser., p. 185. 

 Astarte exaltata Conrad, 1845, Fossils of the Medial Tertiary, p. 66, pi. xxxvii, flg. 6. 



