462 peoceedrs-gs of the geological societt. [may 20, 



Discussion. 



The E-ev. Mr. Ginof, in opposition to the view of the forest-bed 

 being placed above the Chill esford Clay, mentioned that at Easton 

 Bavent, where the latter has been supposed to occur in the cKff, he 

 had seen the forest-bed exposed on the shore. He instanced other 

 cases where the forest-bed, in his opinion, nnderhes the Chill esford 

 Clay and Sands, and supported his views by the evidence of the 

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

 sion of the Mastodon Arvernensl?, the ElepTias meridionalis, E. an- 

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

 tion of the Mammals of the Red Crag. 



Mr. GwYx Jeffkets 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 distinct species into mere varieties of the 

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

 presence in the E-ed 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 

 Eadiolarise and Diatomaceae, and especially of Arachnoid iscus coc- 

 coneis, the Eadiolarise being chiefly of the division Acanthometrae, all 

 three forms being purely marine. 



Mr. Chaeleswoeth 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 recogniziug ex- 

 traneous fossils. He expressed his disappoiutment 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, never have 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. SeaPvLes Wood, jun., denied that the Red Crag was the one 

 homogeneous deposit divided into two beds 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 beiug therefore probably the older. 



Mr. Peestwich, in reply, explained that he did not intend to 

 omit the Kst of Mammalian remaius of the Red Crag, tables of which 

 were appended to the paper : the greater part of them, however, he 

 regarded as derivative. With regard to the relation of the ChiUes- 

 ford beds to the forest-bed, he had never seen a section in which the 

 latter underlies the former ; the Chill esford beds at Easton Bavent 

 are underlain by sandy beds referable to the Xorwich Crag. He 

 considered that some division in the lower bed, as suggested by Mr. 

 Searles Wood, was to be found. 



