PRESIDENT'S ADDRESS. 5 



of the village. The axis of the bed" is unconformable with the 

 valley, which I consider has been formed subsequently. The fossil 

 remains are restricted to one species only, Eleplias meridionalis. 

 The larger bones only of this gigantic animal have as yet been 

 met with, the smaller ones having probably perished owing to the 

 dissolving power of rain water and other atmospheric causes. I 

 hope in the course of the summer to make a thorough examination 

 of the bed in its extension across the plateau, where the superin- 

 cumbent material is thicker and more protective, and to find 

 additional confirmatory evidence of the Pleiocene character of the 

 bed. 



From the evidence of the flora contained in the Norfolk Pleiocene 

 Crags, Professor Prestwich and Mr. Clement Reid are both agreed 

 that the average climate during the Pliocene period was much the 

 same as that of the present day. The gradual dying out of the 

 southern types, and corresponding increase of the northern marine 

 fauna to an Arctic one, they attribute less to general climatic 

 changes, rather than to an uninterrupted communication with the 

 Northern Sea, which favoured the immigration of Arctic species, 

 while the southern fauna having no such communication with the 

 warmer seas of the south would be ultimately overwhelmed and 

 extirpated. Southern forms of freshwater mollusca occur mixed 

 with Arctic marine shells in some of the Crags, leading to the 

 conclusion that both lived at the same time side by side. Oak, 

 beech, elm, pine, fir, and yew occur in the Forest-Bed, and while 

 the few marine animals are of a northern, the land mammalia, 

 25 in number, are of a southern type ; of these three only are now 

 living in Britain and five in any part of the world. 



After the gradual refrigeration of the Pleiocene climate a 

 period of 'intense cold prevailed, modified more than once 

 probably when temperate fauna returned -from their southern 

 temporary refuges in which they had sought shelter. The 

 Boulder Clays of Norfolk are intercalated with lignites and 

 remains of Pleistocene mammalia, showing that considerable 

 changes of climate must Jiave occurred during the deposition. 



