NEWTON: CONCHOLOGICAI. FEATURES OF LENHAM SANDSTONES. II5 



Bolderian to Scaldisian of Belgium, and the Coralline and Red Crags 

 of Britain, With the exception of Ficus reticulata and Papilli- 

 cardhim papillosum, which exist in present seas, the species thus 

 enumerated are extinct. Several of the Lenham species occur in the 

 Bolderian and Anversian beds of Belgium, the latter according to M. 

 DoUfus^ being Vindobonian, and equivalent to his Redonian stage, 

 although attributed by Renevier^ to the later Pontian (=^Messinian) 

 division of the Miocene. The Anversian and Diestian occurrences 

 represent 34 and 30 species respectively, Box-Stones 12, St. Erth 15, 

 and the Coralline Crag 50. It has been urged by Mr. Harmer that 

 the Coralline Crag fauna is younger than that occurring in the Len- 

 ham deposits because several of the older shells found there and 

 that have been previously alluded to are absent in the Coralline Crag 

 beds, a fact more or less accurate, although some important forms 

 do occur in those deposits, such, for instance, as Margariiifera 

 phalcenacea, Glans senilis, Cyrtodaria angusta, Panopma menardi, 

 Terebratula perforata, etc. 



All these facts seem to suggest that the Lenham and Coralline 

 Crag faunas, although showing certain differences of detail, are, 

 nevertheless, to be regarded as presenting a close relationship, and 

 therefore to be considered as of approximately the same age. Marked 

 affinities are also noticeable in the moUuscan faunas of the Coralline 

 Crag and the Diestian beds of Belgium. This is apparent from Mr. 

 Harmer's list of the Diestian species {Quart. Journ. Geol. Soc, 1898, 

 vol. 54, p. 317), in which, out of rather more than seventy forms 

 enumerated, nearly all are stated to occur in the Coralline Crag. 



A considerable proportion of the Anversian species of Belgium, as 

 listed by M. Van den Broeck (Ann. Soc. Mai. Belgique, 1874, vol. 9, 

 pp. 118-121), likewise occur in the Coralline Crag, as out of a list of 

 175 species 80 are recognised as being found in that formation. 



The following table shows the numerical representation of the 

 seventy-seven Lenham species occurring in the principal formations : 

 Recent - - - - 40 species 



Post-Pliocene - - - 23 „ 



Astian - - - - 36 „ 



Plaisancian - - - 40 ,, 



Scaldisian - - - 44 ,, 



Norwich Crag - - - 12,, 



Red Crag - - - 48 ,, 



(probably derived from Coralline Crag). 



1 Bull. Soc. Geol. France, 1903, ser. 4, vol. 3, pp. 256-260. 



2 Chronographie G^ol. — Text Explicatif ; Co7itJ>. Rend, Cong. Geol- Inifrnat, (1894), 

 1897, p. 597. 



