388 Proceedings of Philosophical Societies. [May, 



tions with an intervening formation of marine origin. The strata 

 of the upper freshwater were found to vary from about 30 to 40 

 feet in thickness, those of the lower from 13 to 28 feet, the latter 

 being sometimes lower than the present level of the Mediterra- 

 nean. 



The marine beds which are interposed are from 10 to 1 1 feet 

 thick. 



The freshwater strata are composed of numerous alternating 

 calcareous and argillaceous marls, and compact limestones ; and 

 their organic remains consist of a few bones of land quadrupeds 

 much decayed, a variety of freshwater and terrestrial shells, the 

 latter in the greatest abundance ; the shells differing in species 

 but not in genera from the present inhabitants of the same 

 country ; and lastly, some traces of vegetables, chiefly reeds. 



The marine formations contain ostrese, cerithese, &c. A com- 

 plete list is added of the organic remains ; and from the state of 

 preservation in which the freshwater shells are found, M. Marcel 

 de Serres infers that they lived and were deposited where they 

 are now found ; and from the resemblance of those occurring in 

 the upper and lower freshwater beds, he concludes that the 

 periods at which these two formations were deposited were not 

 very remote from each other. 



The author considers all these formations to be more recent 

 than the calcaire grossiere, and ascribes the alternations of 

 marine and freshwater strata to a return of the sea, such a sup- 

 position being rendered the more probable by the neighbourhood 

 of the Mediterranean, where similar returns are still known to 

 take place. 



Feb. 4. — This day being the Anniversary of the Society, the 

 following gentlemen were chosen as the Officers and Council 

 for the year ensuing. 



President. — Rev. W. Buckland, FRS. Prof. Geol. and Min. 

 Oxford. 



Vice-Presidents. — Sir A. Crichton, MD. FR. and LS. Hon. 

 Memb. Imp. Acad. St. Petersburgh ; W. H. Fitton, MD. FRS. ; 

 C. Stokes, Esq. FRA. and LS. ; and H. Warburton, Esq. FRS. 



Secretaries. — C. Lyel|, Esq. FLS. ; G. P. Scrope, Esq. ; 

 T. Webster, Esq. 



Foreign Secreiary. — H. Heuland, Esq. 



Treasurer. — .J. Taylor, Esq. 



Council.— Ron. H. G. Rennet, MP. FRS. and HS.; R. Bright, 

 MD. FRS. ; Sir H. Bunbury, Bart. ; H. Burton, Esq. ; W. 

 Clift, Esq. FRS. ; H. T. Colebrooke, Esq. FRSL. and E. FL. 

 and Asiat. S. ; G. B. Greenough, Esq. FR. and LS. ; T. Hors- 

 lield, MD. FLS. ; G. Mantell, Esq. FLS.; Hugh Duke of Nor- 

 thumberland, KG. FHS.; W. H. Pepys, Esq. FRS. LS. and 

 HS: ; and J. Vetch, MD. 



