a4 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
defined ; posterior side forming a flattened area, well separated from the other portion of 
the surface by a clearly defined, oblique, and acute angle; the posterior border, at first 
curved, slopes suddenly downwards, nearly in a straight direction, forming an angle at its 
junction with the lower border ; the surface has a few faintly marked, irregular, concentric 
plications. 
Dimensions.—Length, 13 lines ; height, 11} lines ; diameter through both of the valves, 
8 lines. The hinge has not been examined. 
Geological Positions and Localities. 'The fine specimen-figured was collected by J. F. 
Whiteaves, Esq., in the Great Oolite of Kirklington, Oxon. It occurs rarely in the Inferior 
Oolite of Blue Wick ; it was also collected in the roe stone of the Inferior Oolite at Leek- 
hampton Hill by the Rev. P. B. Brodie. 
Carpium coenatum, Phil. Tab. XXXVI, figs. 3, 3a. 
CaRDIUM coGNnatTuM, Phil. Geol. York., i, t. 9, fig. 14. 
— coenatum, Morris. Catal., 1854, p. 192. 
Unitcarpium coenatum, D’Orb. Prodr., Et. x, No. 324. 
— — Oppel. Juraformation, p. 410. 
CaRDIUM — Leckenby. Journ. Geol. Soc., xv, pl. 3, fig. 8. 
Testa ovato-orbiculari, convexa, umbonibus magnis, medianis, subrectis, margine 
antico et postico, elliptico curvato, lunula nulla ; valvis striis concentricis, crebris, tnstructis; 
postice striis radiantibus obliquis decussatis. 
Shell ovately orbicular, convex ; umbones large, prominent, mesial, straight, or directed 
slightly forwards ; the anterior and posterior margins of the valves are curved elliptically ; 
there is no lunule; the whole surface has very densely arranged, delicate, concentric 
striations ; the posterior side is not compressed, but has some oblique, faintly marked 
striations, which produce a roughened surface where they decussate the concentric 
striations. 
The specific characters are not strongly defined, and reside more in the general figure 
than in the ornamentation of the surface; the Cornbrash specimens have a thin, shining 
test, and the striations can scarcely be distinguished without the aid of a magnifier ; the 
posterior side is scarcely so much produced as the other, and the greatest convexity of 
the valves is placed a little posterior to the mesial line; the Kelloway Rock examples 
are smaller. 
Cardium cognatum is nearly allied to an inferior Oolite species, casts of which are 
very common in the Cotteswold Hills; the latter fossils are more ovate, the muscular 
scars more strongly impressed; the test is much more thick; the striations, both 
concentric and oblique, are more strongly defined, especially the oblique striations 
