254 W. S. HtuUeston — On the Yorkshire Oolites. 



Shell ovate, subelongate, with a spire composed of about four 

 whorls, which are slightly tabulate and moderately tumid. Body- 

 whorls relatively large, and somewhat barrel-shaped. The body- 

 whorl, and probably the penult, are ornamented by fine spiral strise, 

 but the condition of the fossil, in this peculiar matrix, is not 

 favourable to close discrimination. 



The length of the aperture is slightly less than half the height of 

 the shell, the outline being elliptical ; the columella is excavated 

 and encrusted, but not plicated, outer lip curved. 



This variety, pullus, has a smaller spiral angle, and a better 

 developed spii-e than Actceon Sedgvici. It is probably the form more 

 likely to be found in higher horizons. There are two specimens in 

 the Leckenby Collection marked " TornateUa, Millepore Bed, Scar- 

 borough," which probably belong to Action pullus. In the same 

 Collection there is likewise a fossil marked " ActcBon, Cornbrash, 

 Scarborough." which cannot be very far removed from this form, but 

 its condition is such that accurate identification is impossible. 



Genus Bulla, Klein, 1753. 

 93.— Bulla undulata. Bean, 1839. Plate V. Figs. 10, 10a. 



1839. £ulla undulata, Bean, Mag Nat. Hist. p. 61, fig. 22. 



1850. Bulla undulata, Bean, Morr. and Lye, Gt. Ool. Moll. p. 96, pi. 8, fig. 8. 



1875. Cylindrites {Bulla) undulata, Bean, Phillips, G.Y., 3rd edition, p. 260. 



Bibliography, etc. — This was one of the discoveries of Bean sub- 

 sequent to the publication of the earlier editions of the Geology of 

 Yorkshire. Phillips in his last edition refers the Cornbrash shell fo 

 Cylindrites, which genus he evidently regarded as more nearly related 

 to Bulla than to Actcson, notwithstanding the plication of the 

 columella. 



Description. — Specimen from the Cornbrash (zone 4), Scarborough. 

 Leckenby Collection. 



Height 31 millimetres. 



"Width in proportion to total height 77: 100. 



Shell oval, ventricose ; marked by broad and irregular lines of 

 growth. Apex perforated ; aperture longer than the body of the 

 shell, rounded at each end, relatively narrow behind, but rounded 

 and excavated in front : outer lip slightly arcuated. 



N.B. — This specimen has been rather compressed. 



Belations and Distribution. — This is a truly common type, the 

 Scarborough fossil only differing from the existing Bulla ampulla in 

 being slightly shorter, and in the apparently more rugose habit of 

 growth : but this latter feature is of little value when we compare 

 shells with fossils. It also varies much in size like Bulla ampulla, 

 some of the Scarborough specimens being much larger than the one 

 figured ; whilst, on the other hand, specimens from the Great 

 Oolite of Minchinhampton, where it is rare, are said to be smaller, 

 and to have the inner lip more sinuated. 



Bulla suprajurensis, Koem. (Ool. Geb. p. 137, pi. 9, fig. 33) is a 

 small representative of this group in the Upper Jura, and since an 



