30 MOLLUSCA FROM THE GREAT OOLITE. 



Locality. It is by far the most abundant of the Great Oolite Cerithia, and may usually 

 be seen sprinkled over the blocks of planking at Minchinhampton Common ; but occurs 

 indifferently in all the shelly beds. 



CERITHIUM LIM^EFORME, Bom. Plate VII, fig. 2. 



CERITHIUM LIMJEFORME, Roemer. 1836. Nordd. Oolith., p. 142, t. 11, f. 19. 

 Goldfuss. Petref., iii, p. 33, t. 173, f. 17. 

 Bronn. Index Palseont., p. 269. 



C. Testa turritd, anfractibus (1 8) depressis, subplanis, cingillato-granulatis trilineatis, 

 granulis majusculis approximates costellas longitudinales formantibm, aperturd ovatd, canali 

 brevi truncato. 



Shell turreted, apex pointed, whorls (7 8) depressed, nearly flat, having transversely 

 nodulated costse, three in number upon each whorl ; the nodules are nearly joined longi- 

 tudinally, presenting the appearance of longitudinal ribs in the young shell ; but in a more 

 adult state the upper row becomes more distinctly separated from the other two, which 

 latter have sometimes an additional row of smaller granules between them. 



This shell, as compared with C. quadricinctum, would appeal 1 to be much more rare ; 

 but as it requires a close inspection to distinguish them, some uncertainty must exist. 



Locality. It accompanies the above-mentioned species in all the shelly beds. Its length 

 does not exceed 3 lines. 



CERITHIUM SEXCOSTATUM. Plate VII, fig. 3, 30. 



C. Testa turritd, lesvi, anfractibus convexiusculis, costatis ; costis (6 7) lonyitudi- 

 nalibus, l&vigatis, rotundatis, angustatis, rectis: aperturd ovatd; caudd obsoletd. 



Shell turreted, smooth ; whorls rather convex, costated ; costa? (7 C) longitudinal 

 smooth, rounded, narrow, and straight; aperture ovate. The ribs do not form a con- 

 tinuous line upon the volutions, a complete circle occupying more than 6, but less than 7 

 costae, whose upper extremities scarcely reach the sutures of the whorls ; the whorls are 

 rather high, their junctions are deeply impressed, the last whorl being equal in length to 

 two fifths of the entire shell. Axis 1\ lines. 



Locality. The white stone of Bussage has furnished our only example. 



CERITHIUM PEXTAGONUM, Arckiac. Plate IX, fig. 22. 



CEKITIIIUM PENTAGONUM, Archiac. Me"m. Soc. G6ol. Fr., torn. 5, p. 384, t. 31, f. 6. 



D'Orfj. Prod. Pal&mt., p. 303. 

 Bronn. Index Palseont., p. 271. 



