﻿10 



MR. E. B. NEWTON ON A EOSSILIEEROUS [vol. lxxii, 



Streptocl/etus sesccostatus, a, Fusiform shell, belongs to the Upper 

 Miocene deposits of Northern Germany and Belgium (Anversian 

 Beds), which are variously regarded as Messinian, Mio-Pliocene, 

 or the Sarmatian-Pontian Series ; in Holland the sj^ecies has been 

 recorded as of Vindobonian age. This is its first acknowledgment 

 as a British fossil, although remains of it are found in the Lenham 

 Beds, a fact, however, published since the reading of this paper. 1 



JFici/s \_Pyrula\ simplex occurs only in the Messinian Beds of 

 Northern Germany, never having been previously determined from 

 British rocks. 



In addition to these species, Gottsche 3 has recorded from the 

 same horizon and country, Scapliander lignarius, Arcoperna 

 sericea, Lcevicardium fragile, and Dentilucina borealis, all of 

 which form part of the fauna of the North-Sea rock. 



On the assumption, therefore, that the limestone belongs to some 

 part of the Crag system, there appears to be ample evidence that 

 it is of older age than the Bed Crag, on account both of the total 

 absence of Arctic species, and of the comparatively large number 

 of extinct forms which have been recognized in it. It is more 

 likely, therefore, to be of Coralline Crag age : for, in addition to 

 the fact that the fauna agrees in the main with the molluscan 

 fauna of that period, there are some lithological features which 

 may be worthy of mention. 



According to the constitution of the Coralline Crag deposits of 

 East Anglia, as explained by Prestwich, 3 the lower beds of the 

 series contain 'irregular seams of shelly limestone' ; in more recent 

 years Mr. P. W. Harmer has also referred to a similar formation 

 in the same deposits as ' tabular layers of limestone, very hard, 

 and difficult to penetrate,' which were discovered in a boring at 

 Gedgrave Hall. 4 I have not seen specimens of these limestones, 

 although it would be desirable to compare them with the present 

 rock. It does seem possible, however, that this North-Sea material 

 may represent the lower portion of the Coralline Crag, and has, 

 therefore, no connexion with Red Crag deposits, which are through- 

 out of a sandy nature and furnish no evidence of intercalated 

 calcareous beds. 



Considering the large number of extinct molluscan species fur- 

 nished by the limestone, namely, 10 out of a total of 23 (or about 

 40 per cent.), as against Searles Wood's computation of the Coralline 

 Crag mollusca made in 1874, that out of 391 species 142 were 

 not now living 5 (thus representing about 36 per cent, of extinct 

 forms), one may infer that, if the North-Sea rock really belongs to- 



1 R. B. Newton, ' On the Conchological Features of the Lenharu Sandstones 

 of Kent & their Stratigraphical Importance ' Journal of Conchology, vol. xv 

 (1916) p. 74. 



2 Verhandl. Ver. Naturwissensch. Unter. Hamburg', 1876-78, pp. 182-85. 



3 Q. J. G. S. vol. xxvii (1871) pp. 123, 125. 



4 Ibid. vol. liv (1898) p. 336. 



5 See Clement Reid, ' The Pliocene Deposits of Britain ' Mem. Geol. Surv. 

 1890, p. 38. 



