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LIMESTONE FROM THE NORTH SEA. 



11 



the Coralline Crag, that formation is pi'obabby of earlier age than 

 it is usually supposed to be at the present day ; and it is interesting 

 in this connexion to note that, in his earlier researches on the 

 Crag mollusca, Searles Wood was of opinion that the Coralline 

 Crag deposits represented the remains of the Miocene Period in 

 England — a view, however, which he afterwards relinquished 1 in 

 favour of regarding them as early Pliocene. Clement Reid placed 

 them in his ' Older Pliocene ' group in association with the 

 St. Erth Beds, the Lenham Beds, and the Boxstones, 3 whereas 

 Mr. F. W. Harmer regards them as the base of the ' Newer 

 Pliocene' Series and younger than the Lenham and Boxstone Beds, 

 which he restricts to the ' Older Pliocene ' division as represented 

 in this country. 3 



It should be also stated that long before Reid and Harmer 

 published their views on this subject, Mayer-Eymar had estab- 

 lished the group-name ' Messinian ' for the later Miocene deposits 

 of Europe, including in it the Lower Crag because a great number 

 of its species were found in the Helvetian stage of the Miocene. 4 



From my own studies of these mollusca, and especially those of 

 the Lenham sandstones, I believe that no great disparity of age 

 separates the so-called ' Older Pliocene ' deposits. The faunas may 

 differ somewhat in detail according to the special environments 

 which governed their existence ; but they all exhibit a strong 

 southern character, and in other ways appear to resemble more the 

 later Miocene life of Europe than that of the succeeding period. 



Judging entirely, therefore, from palseontological evidence, and 

 apart from any physical considerations, I am inclined to regard this 

 limestone as of Coralline Crag; age. 



List of Molluscan Species. 



GASTROPODA. 



Family La.mpusid.2E. 

 Ranella gigantea Lamarclc. (PL II, fig. 1.) 



Ranella gigantea Lamarck, ' Hist. Nat. Anim. sans Vert.' 1822, vol. vii, p. 150. 

 Ranella, reticularis Hoernes, Abhandl. K.K. Geol. Reichsanst. 1853, vol. iii, 

 p. 211 & pi. xxi, figs. 1-2. 



Remarks. — A small example, represented by a cavity in the 

 limestone which, with the aid of a wax squeeze, yields the sculp- 

 ture characters of this species. 



Distribution. — Vindobonian (Austria) ; Plaisancian (France 

 and Italy) ; Recent (Mediterranean). 



1 Monogr. Pal. Soc. 1848, p. v (Introduction) ; ibid. 1857, pp. 301, 302. 



2 ' The Pliocene Deposits of Britain ' Mem. Geol. Surv. 1890, p. 2. 



3 ' Geology in the Field ' Jubilee Vol. Proc. Geol. Assoc. 1909, p. 90. 



4 1 Catal. Syst. Foss. Tert. Mus. Zurich ' pt. 2 (1867) p. 13. 



