﻿Mr. J. Prestwich on the Red Crag of Suffolk. 147 



the local conditions into consideration, eliminating the extraneous 

 fossils of the Red Crag of Sutton, Butley, &c, and excluding the 

 freshwater fossils of the more northern districts, the author regarded 

 the remaining fossils of the two divisions of the Red Crag as being 

 so closely related that the whole group must palseontologically be 

 treated as one. Mr. Searles Wood had given the total number of 

 species of its mollusca as 239 ; to these Mr. Gwyn Jeffreys has 

 added six additional species ; on the other hand, he regarded ninety- 

 nine of them as varieties and extraneous fossils, leaving 146 species 

 belonging to the Red Crag. Of these Mr. Jeffreys has identified 

 133, or 92 per cent., with living species, 115 still being inha- 

 bitants of British seas, 15 being found in more northern seas, and 

 3 in more southern. 



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 extra- 

 neous fossils in the Red Crag, and partly to the difference in the 

 conditions which prevailed in the two areas at that time, and espe- 

 cially to the more littoral and brackish-water conditions which pre- 

 vailed 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. 



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, underlay the Chillesford 

 clay and sands, and supported his views by the evidence of the 

 Mammalian remains of the different beds, and especially the suc- 

 cession of the Mastodon Arvernensis, the Elephas meridionalis, E. an- 

 tiquus, and E. primigenius. He regretted the absence of any men- 

 tion of the Mammals of the Red Crag. 



Mr. Gwyn Jeffreys made some remarks on the subject of spe- 

 cies, and explained how, from a comparison of a large number of 

 specimens, he had in many instances been led to reduce what had 

 formerly been considered 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 Diatomacea?, and especially of Arachnoidiscus coc- 

 coneis, the Radiolaria? being chiefly of the division Acanthometree, 

 all three forms being purely marine. 



Mr. Charleswohth 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 



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