381 The OLiGocEaSTE of the Southern United States 71 



Mississippi. 



Vickshnrg Umesionc, The \'icksbiirg limestoiie extends, 

 across Mississippi, forming as in Alabama, a narrow belt of 20 or 

 25 miles in width. In 1846, Conrad* noted the peculiar charadleT 

 of the fauna of this limestone. He writes, "The formation marks 

 a distindl era in the American Tertiary system, intermediate to 

 the Eocene and Miocene, but more nearly allied to the former, 

 and perhaps it will be proper to class it as a subdivision of the 



Eocene A few of these shells have a striking resemblance to 



species from Dax, Grignon and Bordeaux, and I believe that the 

 A'icksburg Tertiary will prove to have been deposited in an era 

 more nearly allied in age to that of those localities than to the 

 Eocene of Paris or London." 



The typical \' icksburg beds are formed of crystalline lime- 

 stones and marls. 



The Red Bluff beds. At Red Bluff, in Wayne County, is a 

 ferruginous rock, described by Dr. Hilgardf as the Red Bluff 

 beds. These were considered by him as possibly equivalent to 

 the Shell Bluff beds which were referred then to the Vicksburg. 

 The Red Bluff beds are now considered to be hardly separable, 

 faunally, from the Vicksburg of which they represent a lower 

 phase, having more species in common with the Jackson beds. 



SeBion at Mint Spring Bayoti. A secftion of the \'icksburg 

 limestone was made by Mr. Veatch, in 1900, along the course of 

 Mint Spring Bayou, a small creek in the outskirts of \'icksburg. 

 The strata are given in descending geological order. 



* Amer. Jour. Sci., 2nd ser., vol. 2, 1846, p. 124. 

 t Gcol. and Agri. of Miss., i860,, pp. 135-6. 



