(1) 



(2) 



(3) 



(4) 



25-5 



. 31 



. 30 . 



15 mm 



15 



. 28 . 



16 . 



9 „ 



11 



. 11 . 



— . 



J5 



BARBATIA. 39 



urabones only, not well-marked. Postero-dorsal part of the shell sharply com- 

 pressed. Hinge-area narrow, depressed, with close-set ligament-grooves. Orna- 

 mentation consists of many equal-sized radial ribs, separated by narrow grooves, 

 and crossed by less distinct concentric grooves. Occasionally smaller ribs (radial) 

 appear in the grooves. On the postero-dorsal area the radial ribs are broader 

 and more flattened. 



Measurements : 

 Length 

 Height 

 Thickness 



(1) is from Upware; (2) — (4) are from Folkestone. 



Affinities. — The shell is more rounded at the extremities and the umbones are 

 less anterior than in Barbatia Eaulini (d'Orbigny). 



B. marullensis is very similar to Area Baudoniana, Cotteau ; x the latter is of 

 larger size, and may be only an older example of the former. It is also related to 

 A. aubersonensis, Pictet and Campiche. 2 



Area Eugardiana, d'Orbigny, differs in the ventral margin being oblique, and 

 in having coarser radial ribs and less distinct concentric ornament. In Area Galli- 

 ennei, d'Orbigny, the umbones are more anterior (see p. 41). 



Remarks. — I have seen only two examples from the Lower Greensand, both 

 from Upware, but the species has been recorded from Faringdon ; it is not 

 common in the Gault. The concentric ornament is not distinctly seen in the 

 Upware specimens, but that is probably due to the somewhat worn nature of the 

 shell. 



Types. — Specimens which agree well with the figures are in the d'Orbigny 

 Collection, but I could not identify the type with certainty. 



Distribution. — Lower Greensand of Upware, and (fide Morris) of Faringdon. 

 Gault (zones iii, vii, x, xi) of Folkestone. ? Cambridge Greensand (internal 

 moulds only). 



1 'Moll. Foss. de l'Yonne' (1855), p. 86; Pictet and Campiche, "Foss. Terr. Cre't. de Ste. 

 Croix" ('Mater. Pal. Suisse,' ser. 4), pt. 3, p. 432, pi. exxx, fig. 5. 



2 Ibid., p. 433, pi. exxx, fig. 6. 



