126 CRETACEOUS LAMELLIBRANCHIA. 



of Saxony and Bohemia which have been referred to that species by Geinitz and 

 by Reuss. 0. tenuicosta of Renss is the type of G. (Venericardia) bohemica, 

 Griepenkerl. 1 



Remarks. — Numerous specimens of C. tenuicosta from Folkestone have been 

 examined, and they are found to show a considerable amount of variation in con- 

 vexity and in relative height and length. 



Type. — The type came from the Gault of Folkestone, but cannot now be found. 



Distribution. — Gault (zones i, v, vii, viii, ix, xi) of Folkestone. Recorded by 

 Jukes-Browne from the Cambridge Greensand, and by Barrois from the Upper 

 Green sand (zone of Schlo&nbachia rostrata) of the Isle of Wight. 



Cardita Cottaldina, d'Orbigny, 1844. Plate XVIII, figs. 15, 16. 



1844. Cardita Cottaldina, A. d'Orbigny. Pal. Franc. Terr. Oct., vol. iii, p. 91, 



pi. cclxix, figs. 6 — 8. 

 1871. — — F. Stoliczka. Palseont. Indica, Cret. Fauna S. India, 



vol. iii, p. 287. 

 ? 1895. — cf. Cottaldina, E. Tiessen. Zeitschr. der deutsch. geol. Gesellsch., 



vol. xlvii, p. 485. 



Remarks. — Examples of a species of Cardita, which is not uncommon in the 

 Chloritic Marl of Dorset, appear to belong to G. Cottaldina, but their state of 

 preservation is very unsatisfactory. Most of the specimens are internal casts, and 

 in cases where parts of the shell are present the surface is very imperfect, so that 

 the characters of the ornamentation cannot be clearly distinguished. M. Raoul 

 Fortin informs me that the preservation is equally unsatisfactory in the Cenomanian 

 of Rouen, from whence d'Orbigny 's specimens were obtained. 



The shell is quadrate in outline, very convex, carinate, and somewhat longer 

 than high. The ornamentation appears to consist of about 40 ribs, separated by 

 interspaces of great width. 



C. Cottaldina may be distinguished from C. tenuicosta (p. 124) by its fewer ribs, 

 by the length and height being more nearly equal, and by the greater convexity of 

 the valves. 



Measurements : 



(i) (2) (3) 



Length 21 . 20 16-5 mm. 



Height . . 19 . 18 . 14 „ 

 Thickness . 1G . 15*5 . 12 „ 



(1—3) Chloritic Marl. (1) Chaldon, (2) Chard, (3) Balcombe. 

 i ' Palaxmt. Abhandl.,' vol. iv (1889), p. 58. 



