1887.] NATTRAL SCIENCES OF PHILADELPHIA. 401 



Cytherea Sayana f 



Artemis acetabulum 



Venus sp. ? 



Donax variabilis 



Mactra lateralis 



Mactra ponderosa f 



Tellina declivis 



Tellina suhreflexa 



Corhula idonea 



Corbula elevata 



Turhinella Woodi 



Fulgur sp ? 



Nassa trivittata 



Natica sp. ? 



Turrit el la Cumber latidia 



Turritella mquistriata 



Turritella plebeia 



Barnacles 



Echiuoid fragments 



Dendrophyllia (coral) 



Lamna covipressa 



Odontaspis 



Myliobatis 



Crocodilian bone 

 Many of the species occur only in fragments, but the greater num- 

 ber admit of definite determination. Unfortunately, in most in- 

 stances, the depth at which they were obtained could not be ascer- 

 tained, and in so far, therefore, such species give but little positive 

 evidence as to the horizons which they actually rej)resent. But the 

 introduction of a very considerable number of forms, as compared 

 with the number of such forms occurring in the deposits near Shiloh, 

 which are more or less characteristic of the "Virginian" (Middle 

 Atlantic Miocene) deposits, and those of still newer date ("Caroli- 

 nian"), leave no room for doubt that a distinct faunal horizon, 

 the corresjDondent, in all probability, of the Middle Miocene is 

 penetrated by the bore. Again, that the older beds are also repre- 

 sented is proved by the occurrence of Perna maxillata, Pecten 

 Humphreysii, Crassatella melina, etc., but only in the case of 

 the first-named species, Perna maxillata, could the absolute posi- 

 tion depth of some 800 feet in the section be obtained. The po- 



