238 PLIOCENE MOLLUSCA. 



Fossil: Coralline Crag: Sutton, Bojton. Waltonian : Walton- 

 on-NazQ, Little Oakley. Newbournian : Waldringfield, Sutton. Butleyan : 

 Butley. Icenian : Bramerton, Aldeby. St. Ertli. 



Pleistocene: Billockby, March gravels, Selsey, Portland. Holocene : Portrush. 



Lower Pliocene : Italy — Zinola near Savona (Bellardi). 



Upper Pliocene : Italy — Astiano, Bologna. Sicily — Altavilla. France — Nor- 

 mandy, Biot. 



Pleistocene: Isocardia- and Tapes-banks — Cliristiania, Trondhjem (0yen) ; 

 Italy — Reggio, Glravina, Livorno, Valle Biaia; Sicily — Monte Pellegrino, Messina. 



liemarJiS. — AVe have in the English Crag the three varieties of G. linearis 

 figured by Forbes and Hanley (o^). cit.) — one the typical British and southern 

 shell, solid and strongly sculptured (PI. XXVIII, figs. 26, 27), the others less 

 solid and more finely sculptured, generally regarded as northern, viz. var. inter- 

 media (fig. 28) with blunt and more numerous ribs and rounded whorls, and var. 

 pallida (fig. 29), slender, delicately sculptured, with a more elongate spire. These 

 varieties correspond more or less nearly with the Recent Norwegian shell of Prof. 

 Gr. 0. Sars (op. cit.), and the Pleistocene fossils of Prof. Br^gger from Christiania, 

 (ojj. cit.) and of Dr. 0yen from Trondhjem. I have found the typical form from 

 the comparatively southern Crag of Oakley ; the varieties intermedia and pallida 

 are not infrequently met with in the later and more boreal deposits of Butley. 



Var. sequalis (Jeffreys). Plate XXX, fig. 39.^ 



1842. Pleurotoma ? lineare, S. V. Wood, Ann. Mag. Nat. Hist. [1], vol. ix, p. 542. 



1848. Clavatula perptdchra, S. V. Wood, Mon. Crag Moll., pt. i, p. 58, pi. vii, fig. 4. 



1871. Defrancia linearis, var. seqtmlis, Jeffreys, Quart. Journ. Geol. See, vol. xxvii, p. 143. 



1912. Pleurotoma perptilchra, Teseli, Med. v. d. Eijks. v. Delfstoffeu, pt. iv, p. 90, no. 227. 



Varietal Characters. — Much smaller than the type, with more numerous and 

 less prominent ribs, and finer spiral sculpture. 



Dimensions. — L. 4 mm. B. 2 mm. 



Distribution. — Recent : Donegal Bay (Norwich Museum). 



Fossil: Coralline Crag : Sutton, Gomer (Jeffreys). Waltonian: 

 Walton-on-Naze (Kendall). Scaldisien : Holland. 



Bemarhs. — In 1848 {op), cit.) Wood described and figured a minute fossil, having 

 obtained many examples of it from the bed of Coralline Crag at Sutton, which 

 is principally composed of sucli small shells.^ In his Catalogue of 1 842 he had 



1 The artist has not been very successful with this specimen. 



2 Such beds of fine or coarse shells have no zonal value, indicating rather the local and temporary 

 existence of currents of greater or less strength. 



