384 Beports and Proceedings* 



From the Mammaliferous Crag of Norfolk and the Red Crag of 

 Suffolk never having been found in superposition, from the circum- 

 stance that just at the point where the latter ceases the former 

 begins, as well as from the community of so many species of organic 

 remains, the author regarded the two deposits as equivalent ; and he 

 attributed their distinctive characters partly to the extraneous fossils 

 in the Red Crag, and partly to the difference in the conditions which 

 prevailed in the two areas at that time, and especially to the more 

 littoral and brackish- water conditions which prevailed in the Norfolk 

 area. In conclusion, Mr. Prestwich gave a sketch of the physical 

 history of the Red Crag period, describing the mode in which the 

 various phenomena he had noticed had been produced. 



Discussion. — The Rev. Mr. Gunn, in opposition to the view of 

 the Forest-bed being placed above the Chillesford-clay, mentioned 

 that at Easton Bavent, where the latter has been supposed to occur 

 in the cliff, he had seen the Forest-bed exposed on the shore. He 

 instanced other cases where the Forest-bed, in his opinion, underlies 

 the Chillesford clay and sands, and supported his views by the evi- 

 dence of the Mammalian remains of the different beds, and especially 

 the succession of the Mastodon arvernensis, the Elephas meridionalis, 

 E. antiquus and E. primigenius. He regretted the absence of any 

 mention of the Mammals of the Red Crag. 



Mr. Gwyn Jeffreys made some remarks on the subject of species, 

 and explained how, from a comparison of a large number of speci- 

 mens, he had in many instances been led to reduce what had for- 

 merly been considered as distinct species, into mere varieties of the 

 same species. He corroborated the views of the author as to the 

 presence in the Red Crag of numerous fossils of the Coralline Crag. 



Dr. Cobbold stated that, from a microscopic examination of the 

 phosphatic nodules, he had established the existence in them of 

 Radiolarise and Diatomacese, and especially of Arachnoidiscus coc- 

 coneis, the Radiolarise being chiefly of the division Acanthometrae, 

 all three forms being purely marine. 



Mr. Charlesworth commented on the remarkable fact that in a 

 few thousand square feet of Coralline Crag we have a fauna as ex- 

 tensive as the whole British molluscan fauna. He considered that 

 at present the attempt to solve the question of the age of the Red 

 Crag was hopeless, mainly from the difficulty of recognizing ex- 

 traneous fossils. He expressed his disappointment at the fish-fauna 

 of the Red Crag not having been noticed by the author. The teeth 

 which were common to the Eocene and Red Crag had usually some 

 phosphatic matter adherent. Those, on the contrary, which only 

 occur in the Crag, have never any phosphatic matter attached. He 

 therefore regarded the former class as derivative, but the latter as 

 belonging to the deposit in which they occur. 



Mr. Searles Wood, jun., denied that the Red Crag was the one 

 homogeneous deposit divided into two beds as represented by Mr. 

 Prestwich ; he protested against the Walton and Butley deposits 

 being regarded as one and the same, the former bearing more affinity 

 to the Coralline Crag, and being, therefore, probably the older. 



