576 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



portions at least of the area covered by deposits belonging to the 

 Chesapeake group, while the profusion of Oliva literata and Olivella 

 mutica give evidence of extensive sand flats in the area covered by 

 the Duplin marl. Already in the late Tertiary, present day 

 conditions had been approximated along the East Coast. The 

 faunas of Virginia and North Carolina flourished in rather shallow 

 inshore waters into which mud and sand were being freely carried, 

 the waters of the Yorktown basin being slightly but not much 

 warmer than those off the Virginia coast today; while the Duplin 

 fauna was apparently in more direct communication with the Flor- 

 idian life than are the present faunas off Hatteras and Cape Fear and 

 indicate slightly warmer climatic conditions than do those of the 

 Yorktown." 



The Yorktown formation and the Duplin marl are the correlatives 

 of the European stage next younger than the Tortonian, which 

 would be the Sarmatian or Pontian or both. 



CHOCTAWHATCHEE MAKL. 



The study that I made of the Mollusca from the Duplin marl as 

 exposed at Porters Landing, Savannah River, Georgia, 1 and of Mol- 

 lusca from exposures of the same formation in South Carolina, led 

 me to the conclusion that the Choctawhatchee marl of Florida, 

 exposed between Ocklocknee River, on the east, and Choctawhatchee 

 Bay, on the west, is of very nearly the same, if not of the identical, 

 age as the Duplin marl. Therefore, the Choctawhatchee marl and 

 its correlative, the Jacksonville formation of east Florida, are about 

 the same in age as the Sarmatian and Pontian of Europe. 



The brackish water Pascagoula clay of the coastal area in Missis- 

 sippi and Louisiana is probably of about the same age — that is, late 

 Miocene. 



PLIOCENE. 



In the South Atlantic and Coastal Plain of the United States four 

 formations, the Waccamaw marl of the Carolinas, the Nashua and 

 Caloosahatchee marls of Florida, and the Citronelle formation of the 

 Gulf States are definitely considered of Pliocene age. References to 

 literature are not necessary, as they are given in the papers men- 

 tioned in the footnotes on pages 565, 566. At present correlation of 

 these formations with the three recognized European stages, Pla- 

 sancian, Astian, and Sicilian is not warranted. According to Berry, 

 the flora of ' ' the Citronelle formation belongs in the later half of the 

 Pliocene epoch and is directly ancestral to the Pleistocene and 

 Recent floras of the same region." 



i Georgia Geol. Survey Bull. 26, pp. 367-369, 1911. 



