20 CRETACEOUS GROUP 
tous Lignite &c. &c. These strata are surmounted by 
the usual diluvial mass to a depth of ten or twelve feet. 
Mr. Conrad, during his geological journey through the 
Southern states, made some interesting discoveries near 
the town of Wilmington, N. ©. which I shall give in his 
own words: “At this place, I found the Upper Marine 
formation, resting immediately on secondary limestone, 
precisely like that you have described as occurring in 
New Jersey; it is in thin layers, and reposes directly on 
a hard rock which is the equivalent of the Ferruginous 
sand, as it abounds in Lvrogyra costata and other charac- 
teristic fossils. The cretaceous strata are said by intelli- 
gent persons here to extend sixty miles up Cape Fear 
river, and from its mouth coastwise as far north as Cape 
Hatteras.” 
It seems, therefore, that the calcareous and arenaceous 
strata of the American Cretaceous group, wherever they 
have been examined, preserve the same relative position 
as the white chalk and Ferruginous sand of Europe. 
SOUTH CAROLINA. 
Ferruginous Sand.—My friend Dr. Blanding, has 
discovered this formation near Effingham’s mill, on 
Lynch’s creck. The fossils he has brought me are 
chiefly Zxogyra costata. Mar’s bluff, on Pedee river, 
and Nelson’s ferry, on Santee river, afford the belem- 
nites Americanus. 
Calcareous Strata.—The Calcareous strata form an 
extensive basin to the west of the city of Charleston: this 
limestone, which is of the newest Cretaceous formation 
