Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/246

198 198 J. S. GARDNER ON BRITISH CRETACEOUS PATELLID^ ETC.

This species is very variable in general form. The largest speci- men figured measures, 1. 25 millims., b. 19 millims., ht. 8 mil- lims. and was obtained from the cast-bed of the Grey Chalk near Dover (figs. 12, 13). Another from the Chalk Marl of the Isle of Wight is proportionally higher, measuring 19, 14, and 9 millims. respectively (figs. 16, 17). Other specimens more nearly resembling Pictet and Campiche's figure (Terr. Cret. de Ste.-Croix/ pi. xcviii. fig. 10) are from the Cheddington Chloritio Marl (fig. 10); whilst another from Devizes is nearly orbicular. These differences of form are, no doubt, partly caused by pressure.

The excellent figure of E. pelagica, in Passy's ' Geol. de la Seine Inferieure,' is, if any reliance can be placed on figures unaccompanied by descriptions, taken from a specimen of the same species as that here figured from the Grey Chalk; but D'Orbigny's figure of E. pelagica has an altogether different appearance. I have not seen the original specimens ; but should they be identical, Passy's name, published in 1832, would have priority. E. jle.vuosa, De Eyckh., resembles our species, but has the ribs nexuous.

Emargixula DivisiENsis, sp. nov. Upper Greensand. PI. VIII. figs. 19, 20.

Shell ovate, convex anteriorly, flattened posteriorly ; apex sub- central. The cast, which alone is known, bears traces of numerous ribs, reticulated by lines of growth, the ribbing being coarser than that of E. Gresslyi. The fissure is very short, leaving a deep and wide depressed region, very different in appearance from the raised fissural scar of the species last described.

From Devizes, now in the British Museum.

Emarginula SANCTJE-CATHARixiE, Passy. Upper Greensand. PI. VIII. figs. 21, 22.

Shell in form like a Phrygian cap, compressed laterally, convex anteriorly, much hollowed out posteriorly ; apex beak-like and re- curved, overhanging the posterior margin ; sculpture, about 28 ribs, two or three of which are stronger than the rest, reticulated by finer transverse lines. The fissure is short, narrow, and very distinct ; fissural scar broad, depressed, with a narrow central ridge. The dimensions of the figured specimens from "Whitenore are, 1. 12 millims., b. 9 millims., ht. 10 millims. There is no doubt that our shell is identical with the E. sanctce-catharince of Passy, described in the ' Geol. de la Seine Inferieure,' 1832, p. 335, pi. xvi. fig. 1, the figure, however, being extremely obscure ; and in the ' Pal. Frang.' vol. ii. p. 395, D'Orbigny describes the species as possessing 14 or 15 elevated ribs, alternating with others less prominent.

In England it occurs in the Chloritic Marl of Wilts and Dorset ; and specimens are in the British and Jermyn-street Museums. In France it is common to the Mediterranean basin and the Gulf of the Loire, and has therefore a wide range. The European E. rosea appears to be its living representative.