0. Meyer — Species in the Southern Old-tertiary. 71 



Ostrea sellceformis Conr., 0. Alabamiensis Lea, Pecten Deshaysi 

 Lea (incl. P. Lyelli Lea), P. scintittatus Conr., "Scutella" Lyelli 

 Conr., Scalpellum Eocenense Meyer. 



These are exactly the same species as in the stratum b of 

 Claiborne, and the bed in Enterprise is therefore evidently a 

 fades of this stratum. 



3. Profile at Vicksburg, Miss. — Directly in front of the national 

 cemetery near Vicksburg there is a creek (bayou) forming a 

 waterfall, at which the following facts can be observed : At 

 the top there is a stratum with the " Vicksburgian " fossils ; 

 below this follows a stratum of limestone with Pecten, about 

 thirty feet thick; at the base is a clayey stratum with fossils, 

 which must be strictly separated from the upper ones. These 

 strata may be called "Higher," "Middle" and "Lower Vicks- 

 burgian." The Higher Vicksburgian contains the fossils, gen- 

 erally known as Vicksburg fossils. The Lower Vicksburgian 

 is characterized at first sight by the absence of Area Mississippi- 

 ensis Conr., which is abundant in the Higher Vicksburgian. It 

 is very interesting as containing a species of Ccecum and two 

 species of the Pteropod Styliola, two genera hitherto unknown 

 in the American Old-tertiary.* Though I have not found as 

 yet the species mentioned by Conrad, the Lower Vicksburgian 

 is apparently identical with that stratum, which Conrad called 

 Shell Bluff group, f in Vicksburg; but, if so, this name cannot 

 be used for the Vicksburg stratum, because it implies a paral- 

 lelism with Shell Bluff, which is as yet entirely without any 

 proof. 



After the description of the three preceding profiles, the fol- 

 lowing reasons for indicating as the true succession — Vicksburg, 

 Jackson and Claiborne, with Claiborne at the top, may be 

 mentioned : 



1. The Orbitoidic limestone, parallelized by Conrad with 

 Vicksburg, is characterized by Spondylus durnosus and Orbitoides 

 Mantelli. As Conrad found a specimen of Spondylus dumosus 

 in the lower limestone of the Claiborne bluff, he concluded 

 that this lower limestone formed the top of the Orbitoidic 

 limestone. Lyell, upon whose authority the contrary opinion 

 was accepted, could adduce no facts at all against Conrad's 

 theory, and this theory is made more probable by my finding 

 a specimen of the second characteristic fossil, an Orbitoid, in this 

 lower limestone. 



2. If the stratum b, which occurs about a hundred feet below 

 the surface in Claiborne, appears near the surface in Enterprise, 

 a dip of the strata is indicated, which makes it probable that 

 we find older beds as we go in the northwestern direction. 



* Two other species of Styliola occur in Jackson, 

 f This Journal, 2d series, i, 1866, p. 96. 



