SCALA (LAMELLTSCALA) FRONDOSA. 5^3 



1872. Scalaria frondosa, A. and R. Bell, Proc. Geol. Assoc, vol. ii, p. 204.. 



1890. Scalaria frondosa, de Boury, Boll. Soc. Malac. Ital., vol. xiv, p. 29r), no. 70. 



1890. Scalaria frondosa, C. Reid, Plioc. Dep. Brit., p. 256. 



1911. Scalaria frondosa, A. Bell, Journ. Ipswich Field Club, vol. iii, p. 16. 



1914. Scala (SpiniscaJa) frondosa, Cerulli-Irelli, Palaoont. Ital., vol. xx, p. 226, pi. xx, fig. 41. 



1918. Scala (La meUiscala) frondosa, de Boury, MS. 



Specific Characters. — Shell rather small, fragile, im])orForate, conical, turreted; 

 whorls 8 — 9, convex, disjoined, the last much the largest; ornamented by 9 to 10 

 thin, sharply edged, lamellar and membranaceous costse, reflexed, distinctly spinous 

 and projecting above ; spire conical, short, rapidly diminishing in size upwards ; 

 mouth subovate ; basal ridge wanting. 



Dimensions. — L. 12—20 mm. B. 6 — 10 mm. 



Distribution. — Not known living. 



Fossil : Coralline Crag : Gedgrave, Sutton, Boyton. 



Upper Pliocene : Mont« Mario. Scaldisien : Holland (?). 



Remarks. — ;S'. frondosa may be easily distinguished from other Crag species by 

 its texture and sculpture, its sharply-edged and spinous costce and its compara- 

 tively short and conical spire. A difference of opinion has existed, however, as to 

 its relation to some nearly allied forms with which it has been occasionally 

 identified. By Jeffreys (op. cit.) it was referred to a recent Mediterranean species 

 — 8. soluta, Tiberi — but this view is not accepted by M. Cossmann, who places the 

 latter in a different group, Parviscala.^ At one time M. de Boury referred it 

 doubtfully to S. muricata, Risso,' but in a letter recently received from him he 

 now expresses the opinion that, although similar, the Crag 8. frondosa is specifically 

 distinct. Nyst figured in 1 843 a specimen under the present name, but if it is 

 correctly drawn it is not the same as our shelP ; indeed in 1881 he identified it 

 with an allied Crag form, 8. frondiculaj^ 



Wood stated in 1848 that he had only four specimens of 8. frondosa in his 

 collection from the Coralline Crag of Gedgrave and Sutton, but Mr. Bell informs 

 me he has since obtained it from Boyton. A few examples of it may be found in 

 our museums, principally smaller than Wood's type, but it must be still regarded 

 as a rare Coralline Crag shell. I have not found it at Oakley, nor has it been 

 reported from any other locality in the Red Crag. 



Dr. Tesch records it from the Scaldisien of Grave-Oss in Holland, but, as stated 

 above, it seems doubtful whether the typical 8. frondosa has been found in the 

 Netherlands. Seguenza gives it from the Upper Pliocene of Sicily and the 

 Pleistocene of Livorno, but as he identifies his fossils from those localities with 

 8. celesti, Aradas, 8. pumila, Libassi, some other Mediterranean species, his 



1 Ess. Paleoconch. compar., vol. ix, p. 36, 1912. 



2 Hist. nat. de I'Eur. merid., vol. iv, p. 113, pi. iv, fig. 45, 1826. 



3 Coq. foss. Terr. tert. Belg., p. 393, pi. xxxviii, fig. 7, 1843. 

 * Concli. Terr. tert. Belg., p. 87, 1881. 



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