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. C. 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 Exogyra 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 creek. The fossils he has brought me are 

 chiefly Exogyra 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 



