310 Geological Society. 



Reach, the author found impressions of Mactra, Pecten and Cardita, 

 also fragments of fishes' teeth, particularly of the genus Myliobates, 

 likewise several teeth of the genus Lamna, and one belonging to a 

 Notidamus or a nearly allied genus. At Sisters Ferry he observed 

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

 but a highly siliceous clay, which though soft when moist, exhibits a 

 conchoidal fracture when dry, and resembles flint j in some spots the 

 clay also passes into a kind of menilite. 



In conclusion, Mr. Lyell offers the following general observations. 

 The part of South Carolina and Georgia which lies between the moun- 

 tains and the Atlantic, and of which he examined a portion near the 

 Santeeand Savannah rivers, has a foundation of cretaceous rocks con- 

 taining Belemnites, Exogyrae, &c, overlaid first by the eocene lime- 

 stone and marls, and secondly by the burr-stone formation with the 

 associated red loam, mottled clay, and yellow sand. According to 

 Mr. Vanuxem's observations, a tertiary lignite deposit sometimes in- 

 tervenes between the cretaceous and eocene series. The remarkable 

 difference in the fossils of the eocene strata at different points, as 

 the Grove on Cooper river, the Santee canal, Vance's Ferry, Shell 

 Bluff, Jacksonborough, and Wilmington, might lead, Mr. Lyell states, 

 to the suspicion of a considerable succession of minor divisions of the 

 eocene period. That the whole are not precisely of the same age he 

 is willing to believe, but he is inclined to ascribe the difference prin- 

 cipally to two causes : 1st, that the number procured at each place 

 is small and therefore represents only a fractional portion of the en- 

 tire fauna of the period, so that variations in each locality may have 

 arisen from original geographical circumstances ; and2ndly, no great 

 eocene collection has been made from any part of the United States. 



Some of the burr-stone fossils occur in the limestone, and Mr. Lyell 

 thinks the former may bear to the latter a relation analogous to that 

 which the upper marine sands of the Paris basin bear to the calcaire 

 grossier. 



With respect to the conclusion stated in the beginning of the pa- 

 per, that he had been unable to find any beds containing an inter- 

 mixture of cretaceous and tertiary fossils, Mr. Lyell says, it would 

 require far more extended investigations to enable a geologist to de- 

 clare whether there exist in the Southern states any beds of passage, 

 but he affirms that the facts at present ascertained will not bear out 

 such a conclusion. 



The generic affinity of the cretaceous fossils of the United States 

 to those of Europe is stated to be most striking, and Mr. Lyell ob- 

 served in Mr. Conrad's collection from Alabama a large Hippurite, 

 a point of analogy not previously recorded. 



The proportion of recent shells in the eocene strata of the United 

 States appears to be as minute as in Europe, and the distinctness of 

 the eocene and miocene testacea hitherto observed to be as great. 

 Mr. Lyell says, it is also worthy of remark, that the recent shells found 

 in the American miocene beds are not only in the same proportion to 

 the extinct as those of the Suffolk crag, or the Faluns of Touraine, 

 but that they also agree specifically in most cases with mollusca in- 

 habiting the neighbouring sea ; in the same manner as the recent 



