58 FOURTH RKPORT — 1834. 



such size and structure as to preclude the idea that the present 

 puny streams could have had any part in excavating them. They 

 must suggest to every geologist the conclusion that they have 

 been filled by the tide from one escarpment to the other, so 

 that each was a bi'oad bay or short tidal river. 



" Delaivare. Ferrtiginous Sand. — In this State, the blue and 

 grey friable marls extend in the line of the Chesapeake and 

 Delaware canal, from St. George's almost to the western lock. 

 St. George's and its vicinity afford Gryphcea and E.vogyra in 

 great numbers, with Ostrea falcata, and some Belemnites. 

 The deep cut of the canal abounds in Ammonites, Hacu/ites, and 

 Scaphites, without any of the fossils previously mentioned. This 

 locality consists of a series of pyritous sands and clays, of which 

 the shells are decomposed, leaving only the casts." 



" Maryland. — I am informed that the ferruginous sand oc- 

 curs below Annapolis in this state, at which place it is chiefly 

 characterized by Alcyonia. Mr. Conrad obtained at Fort Wash- 

 ington, on the Potomac, a solitaiy valve of Exogyra, indicating 

 the presence of this formation." 



" Virginia. — A writer in the American Journal of Science 

 speaks of the occurrence of Beletnnites and Gryphcece on James 

 river, but gives no locality." 



" North Carolina. Ferruginous Sand. — This is well developed 

 at Ashwood, on Cape Fear river, where, according to the late 

 Mr. William Bertram, there are several beds of dark-coloured 

 marl containing JBelemnites, shark's teeth, pyritous lignite, &c. 

 &c. These strata are surmounted by the usual diluvial mass 

 to a depth of ten or twelve feet." At Wilmington, North Caro- 

 lina, Mr. Conrad found the upper marine formation resting 

 immediately on secondary limestone precisely like that described 

 by Dr. Morton 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 E.vogyra costuta and other 

 characteristic fossils. The calcareous strata are said by intel- 

 ligent persons here, to extend sixty miles up Cape Fear river, 

 and from its mouth coastwise as far north as Cape Hatteras. 



"South Carolina. — The ferruginous sand formation occurs 

 near Effingham's Mill, on Lynch 's Creek. The fossils are 

 chiefly Exogyra costata. Mar's Bluft", on Pedee river, and Nel- 

 son's Ferry on Santee river, afford the Belemnites 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, is mostly yellowish 

 white, friable, and i-eplete with fossils, although the number 

 of species hitherto discovered is inconsiderable. Among these 



