450 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 7, 



may by analogy be applied geologically in accounting for any abnormal 

 condition in the vertical succession of organic remains such as here 

 occurs ? Can it be that such a group of generic forms, allied to and 

 closely resembling those found in the same zoological province at the 

 present day, had a yet older existence in more northern provinces ; — 

 that generic forms of temperate regions have travelled from the north, 

 and have been gradually spread further south, giving, when they 

 encroached upon the more southern forms, a more recent aspect to 

 the faunas of such various geological periods than prevailed in those 

 of the same localities when changes in the distribution of land and 

 water brought back for a time the southern forms which had been 

 temporarily displaced ? — a view almost unavoidably suggested by the 

 fauna of the London Tertiaries as compared with that of the Brackle- 

 sham and associated beds, and confirmed by the independent physical 

 evidence which we have of seas open to the north during the former, 

 and to the south during the latter period. 



Appendix. 



List of the Fossil Shells from the Eocene strata of BracMesham 

 Bay, Sussex. By F. E. Edwards, Esq. • 



(The species in italics occur also in tlie London Clay.) 



MOLLUSCA. 



Cephalopoda. 

 Aturia ziczac, Sow. 

 Beloptera belemnitoidea, Blainv. 

 Belosepia Blainvillii, Desh. 



brevispina, Sow. 



Cuvieri, Desh. 



sepioidea, Blainv. 



Nautilus centralis, Sow. 

 imperialist Sow. 



Gasteropoda. 

 Actceon crenatus, Sow. 



simulatus, Brand. 



sulcatus, Lam. 



, n. sp. 1. 



Adeorbis planorbicularis, Desh. 

 Ampullina depressa, Sow. 



pachyciieila, Soiv. 



patula, Lam. 



Ancillaria buccinoides, Lam. 



canalifera, Lam. 



fusiformis, Sow. 



obtusa, Sow. 



Aporrhais Soiverbii, Mant. 

 Bifroutia bifroiis, Lam. 



disjuncta, Desh. 



Laudinensis, Desh. 



marginata, Desh. 



Borsonia biplicata {Fasciolaria), 



Sow. 

 Buccinum stromboides, Lam. 



Bulla attenuata, Sow. 



Defrancii, Desh. 



Edwardsii, Sow. 



elliptica, Sow. 



expansa, Sow. 



extensa, Sow. 



lanceolata, Sow. 



Sowerbyi, Nyst. 



uniplicata, Sow. 



Cancellaria costulata, Lam. 



evulsa, Brand. 



quadrata, Sow. 



striatulata, Desh. 



Cassidaria ambigua, Brand. 



coronata, Desh. 



nodosa, Brand. 



, n. sp. 



Cerithium angulatum, Brand. 



calcitrapoides, Lam. 



cancellatum, Sow. 



? concinnum, Charlesw. 



Cordieri, Desh. 



cornucopias, Sow. 



cristatum, Desh. 



echidnoides, Lam. 



elegans, Desh. 



giganteum, Lam. 



incomptum, Sow. 



niargaritaceum, Brongn. 



marginatum, Sorv. 



muricoides, Lam. 



