22S MOLLUSCA FROM THE CRAG. 



left valve with one cardidal subbifid tooth, and elevated dorsal margins to interlock 

 with the lateral teeth of the opposite valve. One side of the right valve is somewhat 

 compressed, causing thereby a difference of form in the siphonal scar. 



The nearest approach to this species that I am acquainted with is T. lamellulata, 

 F. Edwards, ' Lond. Geol. Journ.,' vol. i, p. 14, pi. 23, fig. 2, but that shell seems rather 

 more equilateral, flatter, and less truncated, with more numerous elevated lamellae. 

 M. Edwards' specimens are not in very good preservation. 



3. Tellina obliqua, /. Soiverby. Tab. XXI, fig. 7, a — d. 



Tellina obliqua. J, Sow. (not Lamk.) Min. Conch., t. 161, fig. 1, 181/. 

 — Nyst. Coq. Foss. de Belg., p. 107, pi. 5, fig. 2, 1844. 



— — Lyell. Elem. of Geol., 2d ed., p. 299, fig. 14, 1841. 



Spec. Char. Testa subroticndatd, obliqua incequilaterali, crassd^ laviyatd vel irreyu- 

 lariter striata ; antice rotundatd ; postice truncatd, subangulatd ; cardine bidentato, denti- 

 bus lateralibus obsoleiis. 



Shell rather rounded, oblique, inequilateral, thick, and strong; anterior side 

 rounded ; posterior truncated or subangulated, smooth, or covered with irregular lines 

 of growth ; hinge with two cardinal teeth, lateral teeth obsolete. 



Length, 1-f inch. Jieiyht, l-| inch. 



Locality. Cor. Crag, Sudbourn, Ramsholt. 



Red Crag, Sutton, Bawdsey, Felixstow, Ipswich. 

 Mam. Crag, Chillesford. 



This shell first appears in the lower or Coralline Crag, where it is not very 

 abundant ; in the succeeding period, or Red Crag, it may be found in most locali- 

 ties. The species may be called obliquely circular, or rather lenticular, the height 

 being very nearly if not quite equal to the length; the valves are somewhat tumid, and 

 covered with irregular lines of growth, and the posterior side is rather the shorter of 

 the two, with the fold very far back ; this side is compressed in the right valve, but 

 tumid in the left ; the inequality of the two valves at that part having relation to the 

 unequal magnitude of the siphonal scar in the different valves ; the lateral teeth may 

 be said to be wholly wanting, as in the proximate genus Psammobia. 



4. Tellina lata, Gmelin. Tab. XXI, fig. 6, a — d. 



Tellina lata alba. List. Hist. Conch., fig. 253, 1686. 



lata. Gmel. 1/88. (Not Quoy and Gaim.) Fide Lov6n. 



— Midden. Sibiria Keise, vol. ii, part 1, pi. 23, figs. 4, 5. 



— — Lov6n. Ind. Moll. Scand., p. 41, 1846. 



