232 EOCENE STEATA IN UNITED STATES. [Ch. XVI 



Alabama. They also occur in Louisiana and other states both east and 

 west of the valley of the Mississippi. At Claiborne in Alabama no less 

 than 400 species of marine shells, with many echinoderms and teeth of 

 fish, characterize one member of this system. Among the shells, the 

 Cardita planicosta, before mentioned (fig. 216, p. 214), is in abundance; 

 and this fossil, and some others identical with European species, or very 

 nearly allied to them, make it highly probable that the Claiborne beds 

 agree in age with the central or Brackleskam group of England, and with 

 the calcaire grossier of Paris.* 



Higher in the series is a remarkable calcareous rock, formerly called 

 " the nummulite limestone," from the great number of discoid bodies 

 resembling nummulites which it contains, fossils now referred by A. 

 d'Orbigny to the genus Orbiloides, which has been demonstrated by Dr. 

 Carpenter to belong to the foraminifera.f That naturalist moreover is 

 of opinion that the Orbitoides alluded to (0. Mantelli) is of the same 

 species as one found in Cutch in the Middle Eocene or nummulitic forma- 

 tion of India. The following section will enable the reader to understand 

 the position of three subdivisions of the Eocene series, Nos. 1, 2, and 3, 

 the relations of which I ascertained in Clarke County, between the rivers 

 Alabama and Tombeckbee. 



1. Sand, marl, &c, with numerous fossils. 



2. White or rotten limestone, -with Zeuglodon. VEocene. 



3. Orbitoidal, or so called nummulitic, limestone. ) 



4. Overlying formation of sand and clay without fossils. Age unknown. 



The lowest set of strata, No. 1, having a thickness of more than 100 

 feet, comprise marly beds, in which the Ostrea sellceformis occurs, a shell 

 ranging from Alabama to Virginia, and being a representative form of 

 the Ostrea flabellula of the Eocene group of Europe. In other beds of 

 No. 1, two European shells, Cardita planicosta, before mentioned, and 

 Solarium canaliculatum, are found, with a great many other species pe- 

 culiar to America. Numerous corals, also, and the remains of placoid 

 fish and of rays, occur, and the " swords," as they are called, of sword 

 fishes, all bearing a great generic likeness to those of the Eocene strata of 

 England and France. 



No. 2 (fig. 244) is a white limestone, sometimes soft and argillaceous, 



* See paper by the author, Quart. Journ. GeoL Soc. vol. iv. p. 12; and Second 

 Visit to the U. S. voL ii. p. 59. 



•f Quart. Journ. Geol. Soc. vol. vi. p. 32. 



