3Iesozoic and Ccetwzoic Geology and Palcaontology. 101 



Cooper river, about seventeen miles from Cliarleston, South Carolina, 

 Scutella caroUniana, now Ilellita caroliniana, and S. macropliora, 

 now JSncope macrophora. 



In 1843, Mr. Conrad* described, from the Miocene at Newbern, North 

 Carolina, Cliffs of Calvert, Maryland, Petersburg, Virginia, and other 

 places, Carditamera carinota^ C. protracta. Area triquetra, Nucida 

 UciatM, Pectuncidus parilis, Pecten hiforvris, P. tricenariiis, P. vicen- 

 arius, Tellina laevis, Lucina muUistriata^ Amphidesma cequatum, 

 Crassatella turgidula, Crepidida spinosa, Fulgur rugosus, Biiccinum 

 bilex, B. filicatiim^ B. fossidatum, B. Uenosum, B. praeriq^tum^ B. pro- 

 tractum, B. sexdentatum, Cancellaria co7^bula, Oliva dtiplicata, Pyra- 

 midella arenosa, Fusus migrans, F. devexus, Yoluta mutdbilis, Ovula 

 iota, Monodonta exoleta, Echinus improcerus, F. philanthropus, 

 Venus cribraria, Plicatida densata, Crepidida densata. Area propa- 

 hda, now Granoarca propatida, a subgeius of Bat^batia, A. scalaris, 

 Cyrena densata, Jfactra ti'iqicetra, Venus capax, Artemis elegans, 

 Lorlpes elevata, Solen directus, S. ensiformis, Turritella bipartita, 

 Scalaria procera, Pleurotoma niultisectum, Buccinum harpuloides, 

 Fusus cannabinus, Terebra curvilirata, Tiirbinolia pileolus, Sputangus 

 orthonotus, now Amphidetus orthonotus; from the Eocene at Chapel 

 Hill, North Carolina, Tellina arctata; from Pamunkey river, Virginia, 

 Anomia rvffini; and from the Jackson Group, Anomia jugosa. He 

 said, that in a few hours' examination of the Miocene marl, in the 

 vicinit}' of Petersburg, Va., he was enabled to collect about 100 distinct 

 species. This locality is the western limit of the Miocene, which is 

 liere based on granite, and is the spot, in which, to search for the estu- 

 ar}^ and fresh water shells of the Miocene period. The erevation is 

 considerablv more than 100. feet above tide, and as the rise decreases 

 toward the sea, it is probable that the primar}' rocks continued to 

 be uplifted even after the era of the Miocene; indeed, how can we 

 otherwise account for the elevation of fossiliferous beds, even of those 

 of the Post-pliocene period. 



It is an interesting fact that the Miocene estuaries were inhabited 

 by two species of bivalves, now extinct, of the same two genera which 

 still occur in similar situations in Florida and Alabama, that is at the 

 confluence of rivers and bays, where the water is nearl}' fresh. These 

 genera are Gnathodon and Cyrena, both of the family Cyrenidce. The 

 extinct Gnathodon has a considerable resemblance to the recent 

 species, but the Cyrena is vvidely different from the living shell. These 



*Proe. Acad. Nat. Sci., vol. i. 



