20 [Feb., 1846. 



middle of the whorls is largest, and the crente have a different direction 

 from those in the superior rib. A variety occurs with only three ribs, one 

 of the inferior pair being wanting 



Tellina. 



Tellina JTuaffoensis. Plate 1, fig. 20. Subtriangular ; right valve ventri- 

 cose ; anterior side subcuneiform ; margin obliquely truncated, extremity 

 rounded ; beaks medial ; posterior margin regularly rounded ; basal margin 

 nearly straight in the middle ; surface without other lines than those of 

 growth. 



Locality. Occurs with the preceding. 



These two fossils are imbedded in drab colored clay, the geological age 

 of which is uncertain. I have no doubt, however, that it is posterior to the 

 Eocene period. 



MIOCENE SPECIES. 



EtJLIMA. 



Eulima eborea. Plate 1, fig. 21. Subulate, whorls 9 ; suture slightly de- 

 fined ; aperture somewhat oblique, ovate-acute. 

 Locality. Suffolk, Virginia. 



E. migrans. Plate 1, fig. 22. Subulate, very narrow or slender ; suture 

 indistinct ; aperture direct, oblong-ovate, acute. 

 Locality. Occurs with the preceding. 



Odostomia. 

 Odostomia limnia. Plate 1, fig. 4. Subfusiform, polished, whorls 4; con- 

 vex ; suture impressed; aperture oblong-ovate, half the length of the shell ; 

 columella slightly folded. 



Locality. Yorktown, Virginia. 



0. protexta. Plate 1, fig. 5. Subulate, minutely cancellated, with five 

 volutions, those of the spire being subangulated near the base; labrum sub- 

 angulated above the middle ; columella with a prominent fold in the 

 middle. 



Locality. Yorktown, Virginia. 



Delphinula. 

 Delphinula arenosa. Discoidal, whorls 3, slightly convex ; minutely 

 striated longitudinally ; base regularly convex : umbilicus profound. Dia- 

 meter of an inch. 



Locality. Yorktown, Virginia. 



D. lyra. Plate 2, fig. 27. Vide Journ. A. N. S. vol. vii, p. 141. 



Locality. Suffolk, Virginia. 



Bulla. 

 Bulla subspissa. Plate 1, fig. 29. Oblong-oval, thick, ventricose in the 

 middle ; labium rounded or ventricose ; margin of labrum straight above : 

 base minutely umbilicated. 



Locality. Calvert Cliffs, Maryland. 



