OF THE UNITED STATES. 21 
is mostly yellowish white, considerably friable, and re- 
plete with fossils, although the number of species hitherto 
discovered is inconsiderable. Among these, the Ostrea 
cretacea and O. panda occur also in the older cretaceous 
deposits of Alabama. 
GEORGIA. 
The Ferruginous sand appears to abound near Sanders- 
ville in this state, whence I have received a number of 
specimens of the Belemnites Americanus. 
ALABAMA. 
This state presents a vast deposit of both strata, for a 
knowledge of which I am wholly indebted to Mr. Conrad, 
who informs me that the counties of Pickens, Bibb, 
Greene, Perry, Dallas, Marengo, Wilcox, Lownes, Mont- 
gomery, and parts of Clarke, Monroe and Conecuth, are 
chiefly composed of the older Cretaceous strata. In 
Clarke county the newer Cretaceous rock predominates. 
One of the most prolific fossil localities is Prairie bluff, 
in Wilcox county, as will be seen in the course of this sy- 
nopsis. ‘The following diagram will convey an idea of its 
strata : 
Feet. 
2\Loam &ec, 
9 Ferruginous sand, generally indurated 
with Exogyra, Gryphea &c. 
70 Same deposit, in a friable state, with 
abundance of Ostrea falcata. 





River bed. 
The older Cretaceous rock constitutes the long and per- 
pendicular bluff at Demopolis, where it has been ascertained 
