442 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



cene. Others of similar character in South Carolina and Georgia, 

 as at Orangeburg, Aikin, Stony Bluff, and Millhaven, belong to 

 the burrstone formation, which is of the eocene period. 



The species of eocene shells common to the United States and 

 Europe appears to be very small. I have in my cabinet eighty- 

 five species, in a good state of preservation, from Claiborne, Ala- 

 bama, presented to me by Mr. Conrad ; and I procured from the 

 various localities already enumerated in this paper about forty 

 species which I could not identify with the above, or with any 

 which I have seen from Claiborne. Out of these 125 species I 

 have been able to identify the following seven only with European 

 eocene shells : namely, Bonellia terebellata, Trochus agglutinans, 

 Solarium canaliculatum, Infundibulum trochiforme, Cardita plani- 

 costa, Lithodomus dactylus, Ostrea bellovacina. The propor- 

 tion, therefore, of species common to Europe and the United 

 States scarcely exceeds five per cent., and the proportion of 

 species now living and identical with the American eocene shells 

 appears to be still smaller. In regard to geographical represent- 

 ations, I found at least one fourth of the species to be very closely 

 allied to European eocene fossils, while another fourth presented 

 forms differing greatly from any species procured from the eocene 

 strata of Europe, although belonging to genera which are abund- 

 antly represented in these formations. 



March 12. 1845. 



Sir Robert Burdett, Bart., of Ramsbury Park, "Wilts, and Wa- 

 rington W. Smith, Esq. M.A. of Trinity College, Cambridge, were 

 elected Fellows of this Society. 



The following communication was read : — 



On the comparative Classification of the Fossiliferous Strata of 

 North Wales, with the corresponding deposits of Cumberland, 

 Westmoreland, and Lancashire. By the Rev. Adam Sedg- 

 wick, M.A., F.R.S., Woodwardian Professor of Geology in the 

 University of Cambridge. 



The author referring to his memoir on the structure of North 

 Wales, published in the first number of this Journal, for an 

 account of the sequence of the rocks in that district, states that his 

 object now is to bring the successive groups of the Cumbrian 

 mountains into comparison with the three primary divisions of the 

 whole Welsh series.* 



* These divisions are : — 



3. The uppermost slate rocks of the Upper Silurian age, consisting of a series 

 of beds called by the author the ' Creseis flagstone,' from the abundance of that 

 fossil, overlaid by the Denbigh flag, &c. 



2. Roofing slate and greywacke of great thickness, with alternating beds of 

 contemporaneous porphyry. 



1 . Chlorite and mica slate, &c. of Anglesea and the S. W. border of Caernar- 

 vonshire. 



