LYELL ON THE EOCENE BEDS OF NORTH AMERICA. 441 



All the bluffs which I examined on the Savannah River below 

 Briar Creek belonged to the beds above the limestone, and are 

 referable for the most part, if not entirely, to the burrstone form- 

 ation. I observed several sections in the Long Reach in Scriven's 

 County, where the red loam and yellow sand is conspicuous ; and 

 there is a fine section in Hudson's Reach, at a place called Tiger- 

 Leap, where beds of fuller's earth occur. A few hundred yards 

 below Tiger-Leap, where a small creek or brook enters on the 

 right bank of the Savannah River, I found in some of the white 

 clays impressions of Mactra, Pecten, and Cardita, with fragments 

 of fishes' teeth, particularly of the genus Myliobates, several of the 

 genus Lamna, and one of the genus Galeus. These bluffs of loam, 

 clay, and sand are often 80 feet in height ; and after passing Scri- 

 ven I found, in the county of Effingham, similar sections, as at 

 Sister's Ferry and Ebenezer. Tn the section at Sister's Ferry there 

 is not only the brick-red loam, and the red and grey clay and sand, 

 but layers of steatitic clay, which, although soft when moist, be- 

 come hard and acquire a conchoidal fracture when dried. 



On the whole it appears, from the information I obtained, that 

 the less elevated part of South Carolina and Georgia, intervening 

 between the mountains and the Atlantic, has a foundation of cre- 

 taceous rocks, containing Belemnites, Exogyra, and other fossils, 

 above which are, first, eocene limestones and marls, and, secondly, 

 the burrstone formation, with its red loam, mottled clays, and 

 yellow sand. I am informed by Mr. Vanuxem that a tertiary lig- 

 nite formation is sometimes interposed between the cretaceous beds 

 and the eocene limestone ; but I had no opportunity of verifying 

 this fact in the sections which I saw, partly, I believe, owing to 

 the swollen state of the rivers at the time of my visit. The re- 

 markable difference of the fossils found in the eocene limestone at 

 different points may lead some to the suspicion that there exists in 

 this country a considerable succession of minor divisions of the 

 eocene period, but I am inclined to ascribe the circumstance princi- 

 pally to two causes : first, that the number procured in each place 

 is small, and therefore represents a mere fraction of the entire 

 fauna of the period under consideration ; and, secondly, that we have 

 not yet any great eocene collection from any part of the United 

 States. If we had 1000 shells from Alabama instead of little more 

 than 200 (those, namely, which have been found at Claiborne), we 

 should be able to form a more correct opinion respecting the mutual 

 relations of the strata at distinct points, such as Shell Bluff, Jackson- 

 boro', Eutaw, the Santee canal, and Wilmington, North Carolina. 



The difficulty of classifying the tertiary strata of the southern 

 states arises mainly from the wide extent of red and white clays, 

 and siliceous sand, without fossils. The sterile sands which form 

 the soil of the pine barrens in the lower plains of Virginia and 

 North Carolina appear to belong to the miocene period, while 

 those of a large part of South Carolina and Georgia are eocene. 

 Some of the red ochreous and vermilion clays, as, for example, 

 those of Martha's Vineyard and at Richmond, Virginia, are mio- 



