1852.] 198 
As the deposit is a conglomerate and in the vicinity of cretaceous beds, it 
would occur to any one that the presence of a few cretaceous forms could be 
easily explained by supposing the breaking up of a cretaceous bed, and the 
transportation of its debris and included fossils into the eocene sea, where they 
were entombed with the molluscous remains of that period. Nevertheless it is 
evident that the cretaceous shells were filled at the same time, and with the 
same mineral matter as those of the eocene found with them, for the casts of 
both are composed of compact white limestone, Now, excepting the stratum 
on Timber Creek, New Jersey, none of our cretaeeous deposits could furnish 
the mineral matter of either the casts of these shells or the rock in which they 
are enclosed. Between the Delaware and Chattahoochee the cretaceous rocks 
are made up of loose, grey, loamy and silicions strata, without white creta- 
ceous beds; and in Alabama, the rotten limestone, which is the prevailing rock, 
is entirely different from the Wilmington bed; even the cretaceous deposit in 
the vicinity, from which it might be supposed these remains were derived, is 
composed of the usual dark-colored silicious stratum of green sand. It would 
be equally difficult to account for the presence of these fossils, by supposing 
that they remained empty and were subsequently drifted into the eocene sea, 
and there filled with sedimentary matter and buried with the forms of that 
period. At all events, after a careful examination of the locality, as well as 
the fossils, I could satisfy myself only by supposing the inhabitants of these 
shells to have lived and died during the eocene period, to have been cotempora- 
neous with the forms with the remains of which they are buried. 
The fossils to be described are for the most part in the form of casts; fre- 
quently, however, casts of both the interior and exterior of the shells oecur, 
and they are generally so characteristic that there can be but little danger of 
mistake, if even hereafter the shells themselves should be found. 
1. Trocuus nrxus: large; axis very oblique; whorls 5 or 6, flat or slightly 
concave, marked by revolving lines obsoletely cancellated ; suture of the cast 
deep, of the shell basely impressed; umbilicus open, deep. 
Dimen. Spiral angle 74°; ht. 4; br. 5in. 
2. PyruLA AMPLA: Ventricose, ovate; spire depressed; whorls 4, last one 
very large. 
Dimen. Spiral angle 100°; ht. 6 in; br. 4:5 in. 
This fossil is also found in the white limestone of the Santee. 
3. Fusus aBruptus: ovoid ; whorls rounded, ventricose, the last one termi- 
nating abruptly in the canal. 
Dimen. Spiral angle 70°; ht. 6 in.; br. 4 in. 
4. Conus mutinatrus: spire depressed; whorls flattened; side longitudinally 
convex. 
Dimen. Spiral angle 101°; ht. 2:5 in; br. 1:5 in. 
Casts of shell are abundant at Wilmington, N.C., and in the white limestone 
of Alabama. It is also found in the eocene beds on the Santee. They are 
easily distinguished from the other eocene species. In C. gyratus, Morton, the 
spire is more produced; whilst in C. sauridens, Con., it 1s more depressed. 
Casts of the latter have the spiral whorls in nearly the same plane. 
5. Votuta conoipes: conical; spire short; whorls 4, columellar plaits 
numerous. Resembles Conus gyratus. we 
' Dimen. Spiral angle 87°; ht. 2 in.; br. 1 in. 
6. TriGoNntra DIVARICATA: cast of left valve, ribs 15, somewhat acute, con- 
verging towards the posterior margin, arched on the umbones, divaricating 
below. After the sixth rib there is a half rib intercalated. 
Dimen. Length 2 in; br. 1:5 in.; ht. 1 in. 
7. T. tunata: ribs 14, rounded, slightly ventricose: posterior margin cre- 
nulated. 
Dimen. Length 1:75 in.; br. 1:25 in.; ht. 1:25 in. 
