377 I'he Oligocene of the Southern United States 67 



and about 27 transverse ribs. In crossing these the bands are 

 raised so as to appear as nodules. Terminal whorl with ten addi- 

 tional spiral bands, but as the transverse ribs become obsolete over 

 the lower half, there are but four rows of nodules as with the 

 the other whorls. On all except the two earlier whorls is a promi- 

 nent, rounded varix (marking a period of retarded growth), over 

 which the spiral bands are carried, but the transverse ribs are 

 absent. Outer lip spreading; border much thickened within, in 

 older specimens, but crenulated in younger. Sinus of varying 

 depth. In many specimens the basal border of the outer lip ex- 

 tends to the columella and encloses a rounded aperture. Length 

 of shell, 60 mm., width, 24 mm. 



This species resembles both Pyrazisinus campaniilatus , of the 

 Orthaulax bed, and Cerithuun corrugahim, from the Aquitanian 

 of the Bordelais. It differs chiefly in its more prominent sculp- 

 ture from P. campanulahis , and in its greater size and proportion- 

 ately fewer whorls from C. corrugahim, which is, however, un- 

 questionably its European analogue. 



Locality. — Upper Oligocene of the Chipola River at Bailey's 

 Ferry. 



Georgia. 



The Shell Bluff group — Eocene. Ruffin,* in 1843, described 

 the bed characfterized hy Ostrea Geo?gia?ia at Shell Bluff, on the 

 Savannah River, as resting upon the Jacksonian ('Great Caroli- 

 nian' bed). This position would make the Ostrea layer either 

 Jacksonian, or Vicksburgian. 



Lyell,t however, in 1845, obtained typical Claiborne fossils 

 from Shell Bluff, but there was some doubt whether they had 

 been coUedled from the oyster layer. 



In 1865, Conrad'j: referred the bed to the oyster layer at the 

 base of the Vicksburg Bluff, and proposed the name Shell Bluff 



* Report Agri. Survey S. Car., 1843, PP- 22-3, 34. 

 ^ Quart. Jour. Geol. Soc, i, 1845, p. 437. 

 XAmer. Jour. Set., and ser., vol. 41, 1866, p. 96. 



