GEOLOGICAL SOCIETY OF LONDON. 



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South Carolina. — Charlestown stands on a bed of sand, beneath which, 

 is a blue clay, containing shells of the neighbouring seas, also the 

 Gnathodon cyrenoides which is not known as an existing species nearer 

 than the Gulf of Mexico. Mr. Lyell could not ascertain whether this 

 post-pliocene formation rises above high water mark, but thirty miles to 

 the north, on the Cooper River, he found, beneath the superficial sand, 

 a marsh or swamp deposit, from which Dr. Ravenel has procured 

 remains of a cypress, the hiccory, and a cedar; and the author says, 

 as those trees must have grown in that region, although the formation 

 is six feet below high tide, and as the salt water of the Cooper River 

 must now cover much of this swamp deposit, a very modern subsidence 

 along the coast is implied. At the Grove, near the mouth of Cooper 

 River, a soft pulverulent limestone, exposed only in artificial openings, 

 contains fossils diflferent from any known in other localities, but Mr. 

 Lyell conceives it may be an eocene deposit. Between this place and 

 Vances Ferry, on the Santee River, is a continuous formation of white 

 limestone, at least 120 feet thick, in some places hard, in others soft, 

 and composed of comminuted shells and corals ; Jilr. Lyell examined it 

 in company -with Dr. Ravenel. It so precisely resembles in aspect the 

 upper cretaceous deposit at Timber Creek, in New Jersey, that it has 

 been confounded with the cretaceous group, and Mr. Lyell at first felt 

 no doubt that the limestone belonged to it. The testacea and corals, 

 however, prove that it is truly a tertiary formation, and the author 

 sought in vain, through a distance of forty miles, for an admixture of 

 organic remains. In consequence of this and similar mistakes, many 

 fossils have been considered to be both tertiary and secondary, and the 

 beds containing them to be transitions from one order of deposits to 

 another. The upper surface of the Santee limestone is very irregular 

 in outline, and is usually covered with sand, in which no fossils have 

 been found. At Stoudenmine or Stout Creek, a tributary of the Santee, 

 the limestone is concealed by a newer tertiary deposit of considerable 

 thickness, and composed of strata of slaty clays, quartzose sand, brick 

 red loam, and burr stone. Mr. Lyell is not aware of any published 

 account of this formation, but it occurs also on the Savannah River. 

 The clays are soft when wet, yet when dry, they have a conchoidal flint- 

 like fracture, and even pass into a substance resembling menilite. The 

 fossils collected by Mr. Lyell were only casts, and he does not pretend 

 to fix the age of the deposit, but he believes that it is of the same rela- 

 tive antiquity as that of the burr, or mill-stone series of Georgia. In 

 the brief notice of the cretaceous and tertiary strata of the Southern 



