282 [Oct. 1847. 



The upper limestone of Shell Bluff on the Savannah river in Georgia, which 

 contains Ostrea Georgiana and Scutella quinquefaria, overlies the strata which 

 contain species of organic remains identical with those of the Lower Eocene of 

 Alabama and Virginia, none of which has yet been found associated with the 

 two characteristic fossils above named. On the other hand, the Ostrea Georgi- 

 ana occurs at Jackson, Mississippi, where its position is said to be below the 

 Vicksburg group. It is therefore the line of demarcation between the Upper 

 and Lower Eocene. 



FOSSILS OF THE NEWER EOCENE OF MISSISSIPPI. 



Dentalium Mississippiensis. 



Curved, attenuated above, longitudinally striated, the lines alternated in size, 

 Length 2 1-10. Abundant. It differs from D. thalloides, nob., in having more 

 numerous and much less prominent lines. It is very abundant. 



There is another species which occurs in fragments. It is small, rare, and is 

 smooth, polished and curved. 



Fissurella Mississippiensis. 



Suboval, rather elevated, with numerous unequal radiating lines, and fine 

 transverse lines, giving a minutely granulated appearance to the shell ; foramen 

 oval, submedial. Length , very rare. 



An echinated species occurs apparently identical with I. trochiformis of Paris, 

 and of Claiborne, Alabama. 



Solarium triliratum. 



Discoidal, with three thick approximate ridges on the periphery; suture 

 channelled ; volutions with oblique impressed lines, and 2 fine revolving lines 

 on each whorl; base convex with three revolving impressed lines that near 

 the umbilicus profound, and with coarse rugose transverse lines. Diameter 

 "7-10. Not common. 



Bulla crassiplica. 



Cylindrical, narrowing towards the base, smooth and entire ; fold at base 

 thick and prominent. Length 2-10. 



Abundant on Dr. Smith's plantation, 6 miles N. E. of Vicksburg. 



1 . Cyprcea spheeroides. 



Short ovate, subglobose ; posterior end narrow; base rounded; aperture nar- 

 row, the margins with numerous teeth. Length l\. 



Very rare. Mr. J. D. Anderson, of Vicksburg, found one, and I obtained only 

 one during the two weeks employed in collecting the fossils around Vicksburg. 



2. Cyprcea lintea. 



Ovate, elevated, ventricose, with four approximate equal impressed lines ; 

 base ventricose, profoundly striated ; labrum margin much thickened, profound 

 ly striated ; summit of the labrum prominent ; base slightly produced. Length 

 6-10. Rare. 



Narica Mississippiensis. 

 Subglobose, revolving lines fine, regular, equal ; longitudinal wrinkles very 



