BIVALVIA. 53 
general aspect resembles 7: duplicata, Sow., but it has no bifureating coste near to the 
lower border, and is also destitute of concentric costa near to the apex. The sole specimen 
at our disposal is imperfect at the posterior extremity; it has twenty cost, and would 
require about four others to complete its surface. Possibly Zrigonia Cybele, D’Orb., 
from the Great Oolite of Luc, may not differ from this species, but the seven words allotted 
to it in the ‘ Prodrome’ of that author are insufficient to characterise it. 
The figure is nearly that of an equilateral triangle, each of the sides having a length 
of about an inch. 
Geological Position and Locality. In rubbly, hard, ferruginous Oolite (Great Oolite) 
from the Box Tunnel; communicated by W. Walton, Esq. 
Carpium tincuLatum, Zyc. Tab. XXXIII, figs. 2, 2a; Tab. XXXV, figs. 11, 11a. 
Testa ovato-oblonga, mediocriter convexa, umbonibus prominentibus, medianis, subacutis, 
valvis marginibus ellipticis curvatis, rugis concentricis irregularibus, striisque tenuibus, 
delicate impressis ; postice strits obliquis regularibus decussatis. 
Shell ovately oblong, moderately convex ; umbones prominent, mesial, and subacute ; 
the anterior, posterior, and inferior margins of the valves are elliptically curved ; the 
surface has numerous irregular, concentric ruge, and delicate, regular striations ; the 
posterior side has some regular, oblique striations, which decussate those which are con- 
centric. The height and the transverse diameter are equal. 
Allied to Cardium cognatum, Phil., but the latter has much greater convexity, it has 
larger and less pointed umbones, its surface is also destitute of the concentric rugee and 
striations. 
Geological Position and Locality. The Great Oolite of Kirklington, Oxon., collected 
by J. F. Whiteaves, Esq. 
Carpium incertum, Pail. Tab. XXXV, figs. 14, 14a. 
Carprum incertum, Phil. Geol. York., i, pl. 11, fig. 5. 
Unrcarprum incertum, D’Ord. Prodrome, i, p. 279, No. 323. 
Carpium rncertum, Morris. Catal., 1854, p. 192. 
Testa suborbiculari convewa, levi, umbonibus submedianis elevatis subacutis tncurvis, 
margine antico concavo, lunula subnulla ; latere postico planato angulo obliquo formante, 
margine postico subrecto inferne angulato ; lateribus plicis concentricis paucis, irregularibus 
et tenurbus. 
Shell suborbicular, moderately convex, smooth ; umbones mesial or slightly antero-mesial, 
elevated, acute, and incurved; anterior border concave and rounded; lunule scarcely 
