OF SOUTH CAROLINA. 201 
That rivers did exist is proved by the presence of estuary shells. I found, in the Miocene of 
Virginia, shells of the genus Cyrena and Paludina; the genus Gnathodon has been long known 
as acommon Tertiary form. And if the inclination of the Tertiary plane bore any analogy to that 
which it has at present, it should not excite surprise that there are so few fresh water shells found. 
The rivers of South Carolina abound in fluviatile shells, above the line of brackish water, and 
yet, after the closest examination, [ was unable to find a single fragment of such shells at the 
mouths of the rivers in the deposits now forming; nor are there any found in the P. Pliocene beds. 
The reason is this: there is a space of several miles between the line of brackish water and that 
where marine shells can live; in this interval, therefore, neither marine nor fluviatile molluscous 
animals can exist; and as the rivers flow so slowly over their beds, the water has not sufficient 
transporting power to bring down even a fragment of a shell. Under these circumstances it is 
impossible that any mixture of fluviatile and marine shells can take place.* 
That the rivers had scooped out their channels in the Cretaceous and Eocene beds of the State, 
before the P. Pliocene was converted into dry land, cannot be doubted, for but a few miles in extent 
of the coast was below water, and the rest must have been drained, to say nothing of the estuary 
shells found in the P. Pliocene beds, at the mouths of the present rivers. 
I have shown that the coast was elevated, since it was inhabited by the present Fauna, to the 
height of at least five feet. Now it is scarcely probable that this last uplifting force should have 
coincided so completely with that which had previously converted the Tertiary into dry land, as 
not to alter the course of the rivers. A slightly greater elevation of the north-eastern corner of the 
Tertiary plane would give the rivers the tendency they have at present, to encroach upon their 
right banks; and should a corresponding elevation of the north-western corner take place at any 
future period, they would gradually return to their former beds. 
Recent SHELLS OF THE Coast oF SourH CAROLINA.t 
The following recent shells were picked up on the beach, along the coast, and will serve for com- 
parison with the fossil species. Some of them, however, were found attached to sponges and other 
floating substances, and may not strictly belong to the inhabitants of the coast; others are only 
found in fragmeuts, thrown up by storms, and a few probably belong to the P. Pliocene. 
Cemoria alternata, Say, Buccinum obsoletum, Say, 
Syn. Fissurella  “ « Syn. Nassa a a 
Infundibulum depressum, “ B. trivitatum, sf 
Syn. < centralis, Con. “ vibex, 
Dentalium eboreum ? Mt “ acutum, Wy 
Bulla canaliculata, Say. “ unicineta Me 
Syn. Volvaria “ i “ Junatum, Ms 
Auricula bidentata, ¢ Terebra dislocatum, 
* The deposits now forming will contain land shells, for [ saw, in the bay, near the battery, the little Pagurus, or hermit-crab, so 
common there, running about with Bulimus decolla us, of which it lrad taken possession. 
tIn making this collection I was kindly assisted by my friends, F. S. Holmes, Esq. and Dr, Burden. 
51 
