8'2 Bulletin 15 392 



PART m. 



Comparison and Correlation of the Oligocene of the 

 Southern States with That of Western Europe. 



Resemblances of the European Oligocene Fauna to That of the 

 Southern States. 



Foramiyiifera . That foraniiniferal life reached a remarkable 

 development during the deposition of the Vicksburg limestone is 

 established by the facft that many layers of this rock are formed 

 almost wholly of the remains of Orbitoides. The wide geographical 

 distribution of this genus, from Florida to Louisiana, contrasts 

 with the very limited area in which the nummulites flourished at 

 a slightly later period. 



A simultaneous developeiiient of forarainifera occurred in 

 western Europe. In the Adour limestone, Nummidites intermedia 

 and other species abound. In the Gironde valley, the Asterias 

 limestone contains Archiacina armorica in considerable numbers, 

 while the limestone of Rennes is charadlerized by this species. 

 In Germany, foraminiferal developement in the Oligocene period 

 was somewhat later, occurring chiefly during the deposition of 

 the Septaria clays. 



Echi7ioderinata. The Chattahoochee beds of Georgia and 

 northern Florida show a developement of Echinodermata as rich 

 as that of the analogous, but somewhat earlier, fauna of the 

 Asterias limestone of the Gironde. 



Comparison of molluscan species. Conrad was one of the first 

 to attempt a comparison of the Tertiary molluscan species of 

 Europe and America. In his check list* he enumerates some five 

 species as common to both continents. Later, in 1833, f he added 

 eleven, but in a subsequent article, J he reje(5led all except two of 

 these, and added several others. Ultimately all were rejedled 

 excepting those originally published. 



* Smith. Miss. Col., No. 200, 1866. 



jTert. For., p. 34. 



X Anier. Jour. Set., 2nd ser., vol. i, p. 219. 



