Eocene Fossils of the United sin 211 
Eocene Sueuss. Ff 
SILIQUARIA. —— 
The genus Siliquaria of Lamarck, ‘is not of earlier origin than 
the Eocene period. ‘The one species I have described is the only 
oné hitherto discovered in this country, either recent or fossil. 
Chenu figures sixteen species, five of which are fossil in the 
tertiary strata of France. Deshayes enumerates five species in 
the Paris basin, (Eocene. ) 
Sinrquaria viris. Irregularly contorted, rounded, longitudi- 
nally striated; the strie disappearing on the lower part of the 
shell; volutions more regular and approximate towards the apex, 
and the longitudinal strie prominent ; fissure inarticulated. (Plate 
I, fig: 1.) 
Siliquaria vitis, Con. ; Foss. Shells of Tert. Form., p. 36, Aug. 
1833. 
S. claibornensis, Lea, Cont. to Geol., Plate I, fig. 1, Dec. 1833. 
Chenu, Plate IT, fig. 15 
Claiborne, Alabama. 
This species is not uncommon, but it can only be obtained in 
fragments ; it is much contorted, and I have seen it in the bluff 
more than twelve inches long. 'The volutions resemble those of 
S. anguina, and the longitudinal lines upon them are rather coarse 
and slightly prominent. 
DenTALium. 
The genus Dentalium of Linnzus, has been observed in the 
Lias and great Oolite of England. In the United States it has not 
been found of older date than the Eocene period. ‘'T'wo species of 
that formation, and two of the Miocene, comprise all that have 
come under my observation. ‘The Miocerie, D. dentale, is iden- 
tical with the recent shell which inhabits the coast of Massachu- 
setts. Ihave not met with another recent species on the coasts 
of the United States, except a white, very slender and delicate 
one which is common on a part of the southern coast of Florida, 
and a single specimen of Ditrupa gadus, which came up on the 
lead in deep water in the Gulf of Mexico. This species is also a 
Miocene fossil in Virginia. 
Denratiom THALLoipes. Slightly curved, most so towards the 
apex, where it israther suddenly bent; ribs prominent, strieeform, 
alternating with fine lines; the lines sometimes double ; ribs most 
