8 



AP] 



PENDIX. 



NAMES. 





SYNONYMES. 



Cytherea Poulsoni, 



Conrad. 



C. globosa, 



subcrassa, 



Lea. 





Nuttali, 



Conrad. 





perovata, 



" 



C. comis, 



Hydana, 



U 



Gratelupia Moulinsii, 



Astarte tellinoides, 



u 



K A. Nicklinii, 

 f A. sulcata, 



Stalagmium margaritacemr 



[,Conrad. 



Myoparo costatus, 



Corbula oniscus, 



u 





nasuta, 



a 



C. Murchinsonii, 



Mactra praetenuis, 



c< 



M. Alabamiensis, 



decisa, 



u 





parilis, 



u 



M. pygmaea, 



Erycina aequorea, 



u 



Mactra Grayii, 



rectilinearis, 



u 





Amphidesma linosa, 



« 





tellinula, 



it 





profunda, 



(4 





Lutraria papyria, 



(I 





lapidosa, 



It 





Psammobia filosa, 



u 





eborea, 



(( 





Fistulana elongata, 



Desk. 





Balanus ostrearum, 



Conrad. 





Serpula ornata, 



Lea. 





squamulosa, 



Conrad. 





Dentalium thalloides, 



" 



D. alternatum, 



Lea. 



The Middle Tertiary includes a number of deposits which differ considerably 

 from each other in the relative number of extinct and existing species, and their 

 age is not clearly ascertained. It may include fossils both of the Miocene and 

 older Pliocene periods ; to the latter, some deposites certainly belong. I formerly 

 applied the term Lower Tertiary to what has been called the Plastic clay of this 

 country ; it is now used to designate the oldest of the fossilliferous tertiary beds. 



