CARDITA. 127 



Distribution. — Chloritic Marl of Balcombe, Cerne, Chaldon, Clialmingtoii, Cliard, 

 Maiden Bradle}', and Maiden Newton. Recorded by Jukes-Browne from the 

 Chloritic Marl and the zone of Schlocnbachia carians of the Isle of Wi"-ht. 



Cardita, sp. 



Specimens of (Jiirildn from which the shell has disappeared, but showing traces 

 of the ribs, are found in the Chalk Marl of Ventnor, Folkestone, etc. These are 

 too imperfect for specific determination. A specimen from Riugmer was figured 

 by Sowerby,^ and was subsequently regarded by d'Orbigny- as an example of his 

 G. ditbia. 



Somewhat similar specimens also occur in the Upper Greensand of Devizes. 



Cardita cancellata, Woods, 1897. Plate XVIII, figs. 17, 18. 



1897. Cardita cancellata, H. Woods. Quart. Jouru. Geol. Soc, vul. liii, p. 390 



pi. xxviii, tigs. 2 — 5. 



Description. — Shell oval, slightly inequilateral, inflated, postero-dorsal part 

 compressed, faintly carinate; length rather greater than height; margins rounded. 

 Umbones moderately prominent, curved anteriorly. 



Ornamentation consists of a large number of radial ribs sepai^ated l)y narrow 

 furrows, and crossed l)y numerous concentric ribs, giving a nodular appearance at 

 the points of intersection. The concentric ribs are moi'c distinct on the anterior 

 part and the radial ribs more distinct on the median and posterior parts of the 

 shell. Margin of valves finely crenulate. 



Measurements .- 



(1) (2) (3) 



Length . 18 . 16 . 13 mm. 

 Height . 16 . 14-5 . 12 „ 

 (1 — 3) Chalk Kock, Cuckhamsley. 



Ajjiinfies. — This species is more inflated and more rounded than G. tcnuicusla 

 (p. 121), and possesses more numerous radial riljs with narroAV furrows and 

 strong concentric ribs instead of lamina?. 



The concentric ribs distinguish G. cancellata fi'oni the forms desci-il)ed by 



1 ' Mill. Couch.,' vol. iii (1820), p. 106, pi. cclix, fij;. 3 (the orighiul is now in the Britisli Musoiim). 

 Venericardia'i Maiitell, ' Foss. S. Dowiis' (1822), p. 12»->. 



2 'Pal. Fraiiv- Terr. Cn't.,' vol. iii (18-44), p. 92, pi. cclxx, H^s. 1—5. Uiu-rau-er, • .Ubuni 

 Palcoiit. de la Sarthe' (18(37), p. 13, pi. xvi, tigs. 14—18. 



