192 
PROCEEDINGS OF 
Univalves . 
Crepidula fornicata, Say. 
Crepidula unguiformis, Lam. 
Cryptostoma perspectiva, Say. 
Fulgur carica. 
Bivalves. 
Anomia ephippium, Lam. 
Area ponderosa, Say. 
Area transversa , Say. 
Amphidesma cequale, Say. 
Amphidesma bellastriata, Conrad. 
Artemis concentrica. 
Cumingia tellinoides, Conrad. 
Cytlierea Say ana, Conrad. 
Cardium magnum , Born. 
Cardium isocardia, Lam. 
Gnathodon cuneatus , Gray. 
Lutraria canaliculata, Say. 
Mactra lateralis, Say. 
Univalves. 
Oliva litterata, Lam. 
Terebra dislocata. 
Vermetus lumbricalis. 
Bivalves. 
Nucula limatula, Say. 
Nucula proximo, Say. 
Nucula acuta, Conrad. 
Pholas costata, Lam. 
Pecten dislocaius, Say. 
Solecurtus caribams, Lam. 
Solen ensis, Lam. 
Tellina alternata , Say. 
Tellina lintea, Conrad. 
Tellina lusoria, Say. 
Venus permagna, Conrad. 
Venus cancellata. 
I have alluded in this essay to the fact that the eocene and miocene are not con¬ 
nected by a single species common to both. It is equally remarkable that very few 
are common to the miocene and the newer deposits, and they, with one exception, 
are recent species. The conclusions derived from my investigations are, that the 
American tertiaries are of the eras of the eocene, miocene, and post-pliocene, and 
that the newer pliocene is either wanting, or has not yet been observed. 
In concluding this brief sketch of a portion of the tertiary region, I will take 
occasion to remark, that it is my intention when I have fulfilled my obligations to 
the State of New-York, in publishing the organic remains in connection with its 
geological survey, to investigate the Atlantic tertiaries more thoroughly, and to sub¬ 
mit the results of my labors to the National Institution. In the mean time, gentle¬ 
men who reside within the limits of that extensive district would contribute greatly 
to the advance of American geology, if they would send to the National Institu¬ 
tion specimens, in good condition, of all the various organic remains on their 
plantations. 
DESCRIPTIONS OF NEW TERTIARY FOSSILS. 
LOWER TERTIARY OR EOCENE FOSSILS, 
OSTREA .—(Lin.) 
Ostrea sellaformis, pi. 1, fig. 1.—This singular oyster, the history of which I 
have briefly given, appeared so important, in a geological point of view, that I have 
here introduced a figure of the species, although it had been published, in 1832, in 
my “ Fossil Shells of the Tertiary Formations,” page 27, pi. 13, fig. 1, 2. The 
