170 GEOLOGICAL SURVEY 
In the Cretaceous formation of Alabama it presents a like variation in size; yet it can scarcely 
be mistaken for any other, especially where several specimens are examined, for the characteristic 
radiating lines of the upper valve will be seen. I found this fossil near South Washington, N. C. 
with Belemnites Americanus, and it is identical with the ponderous variety on Santee. 
In the green sand at Mazyck’s I found several specimens of Terebratula Harlani, Mort. var. B. 
a cretaceous fossil of New Jersey, which Dr. Morton recognised at once. 
Plagiostoma gregale, Mort. which is found at the same locality, is a Cretaceous fossil: it is 
found abundantly in the coralline bed at Pooshee. It is always attached to other fossils, but the 
squamous plates and strive within, can always be observed. Ostrea panda, an undoubted Creta- 
ceous fossil, is a very common EKocene form in South Carolina. 
Mr. Lyell admits O. cretacea,* Mort. a well known Cretaceous fossil of South Carolina and Ala- 
bama, among the fossils common to the “ Orbitoidal” limestone of St. Stephens. 
In 1846 I happened to be in Wilmington, during the progress of an excavation in the conglomerate 
of that place, for the foundation of a distillery. The excavation was made on the side of the hill 
on which the city stands, and in the upper part of the conglomerate, where it was in contact with 
the Miocene. I found the surface perforated with lithodomous shells of Miocene species, showing 
that it was the bed of the Eocene ocean at the time that the latter formation was quietly depo- 
sited on it. 
I was not a little surprised to find here a Trigonia, at least related to T. thoracica, Mort. if not 
identical with it, together with several well characterised casts of Ammonites placenta, Dekay, a 
fossil found in the Cretaceous beds of Delaware, and in those of the Peedee, South Carolina. 
Seeing that this bed is a conglomerate, I set myself to examine the probability of these fossils 
being washed from the Cretaceous beds, higher up the river, upon which this rests. 'The conglom- 
erate is composed, for the most part, of rolled calcareous pebbles, agreeing with the mass in which 
they are embedded, and it is well known that, lithologically, the cretaceous beds of North and 
South Carolina are entirely different, and hence I could not fail to detect any thing brought from 
that formation. The casts are composed of the white limestone; and the casts of Kocene fossils, 
with which they are associated, are so perfect that I was forced to the conclusion that the molluscs 
belonging to these shells lived and died where they are entombed. 
I did not find here all the fossils that Mr. Lyell identified, but I recognised Crassatella alta, Con. 
an Hocene fossil of James River, Va. and of Claiborne. I have shown that this conglomerate is of 
the same age as the lower beds of the Santee, at Vance’s Ferry, where several fossils, found with 
these casts, occur. We have, at least, then, the following species common to both formations. 
Ammonites placenta, Dekay, Grypheza mutabilis, Mort, 
Terebratula Harlani, Mort. Ostrea panda, es 
Plagiostoma gregale, “ Trigonia thoracica? “ 
Besides these, there are at least two species of Echinoderms, which I have not thought proper to 
insert, till Prof. Agassiz’s revision of American Echinoderms is completed. 
*Am. Jour. Sci. and Art, Sept. 1847. 
