36 Environment of Tertiary Marine Faunas [234 



THE ENVIRONMENT OF THE TERTIARY MARINE 

 FAUNAS OF THE ATLANTIC COASTAL PLAIN 



By JULIA A. GARDNER 



The Miocene and Pliocene deposits of the Atlantic Coastal 

 Plain have now been mapped in detail from New Jersey to 

 North Carolina and the 'contained faunas, which are prolific 

 and varied, have been rather fully described. 1 



The following formations have been recognized in the 

 Middle Atlantic region : 



Maryland Virginia North Carolina 



Pliocene : "Waccamaw 



Yorktown Yorktown-Duplin 



, St. Mary's St. Mary's St. Mary's 

 Miocene: J \ J J 



Cnoptank 



Calvert Calvert 



All of these formations contain extensive molluscan faunas 

 and very large collections have been available for study and 

 comparison. An idea of the richness of these faunas may 

 be obtained from the following census of the faunas of the 

 respective formations : 



No. of species in genera 



Waccamaw 325-335 130 



Yorktown 364-378 143 



Duplin 420-431 154 



St. Mary's 326-344 129 



Calvert . 80-83 50 



1 The more recent literature includes the following : 

 Whitfield, R. P., Hon. U. 8. Geol. Survey, vol. xxiv, 1894. 

 Clark, Martin, Glenn and others, Miocene vol., Md. Geol. Survey, 



1904. 

 Gardner, J. A., "The Miocene and Pliocene Faunas of Virginia 



and North Carolina," Prof. Paper U. S. Geological Survey. 



(In press.) 



