128 W. H. midkHton—The Yorkshire Oolite. 



Bibliography, etc. — No description has eA'er been given of this 

 species, and Phillips's figure is turned in such a way as to show 

 nothing of the twist in the columella, which would seem to exclude 

 it from the BuUidce. Those foreign authors who have been bold 

 enough to speculate in this connexion have generally regarded this 

 species as a Bulla. Thus Brauns (Ob. Jura, p. 239), in describing 

 Bulla Hildesiensis, Roemer, refers to Bulla elongata. De Loriol also 

 (Et. Supr. Jurass. de Boulogne, vol. i. p. 38) appears to conceive that 

 Bulla elongata is a true Bulla, having certain " rapports " with Alcera 

 Beaugrondi. 



As all the specimens accessible to me are in a wretched state of 

 preservation, I can only suggest that the species in question may 

 belong to the second section of Cylindrites, which in the sunken 

 character of the spire and thinness of the outer lip approaches 

 Bulla. 



Description. — Imperfect specimen. Passage-beds of the Lower 

 Limestones, Scarborough Castle (my Collection). 



Lene;th 38 millimetres. 



Width 17 



Shell ovate-elongate, contracted at either extremity, but more so 

 anteriorly. Spire composed of few whorls, smooth, and showing no 

 lines of increase. Shell substance rather thick, except on the outer 

 lip. Aperture long and narrow throughout, but more especially 

 towards the posterior extremity. The excavation of the columella 

 is gradual ; near the base it is strongly twisted and directed outwards 

 so as to meet the outer lip with a sharp curve. (N.B. — The anterior 

 extremity of the aperture is broken away in Fig. 8.) 



Belations and Distribution. — Cylindrites elongatus is excessively 

 plentiful in the Passage-beds and body of the Lower Limestones of 

 the Tabular Hills, where, along with GervilUa avicidoides, it con- 

 tributes largely to the shell-beds of that horizon. It is almost un- 

 known in the Coralline Oolite, and has never, to my knowledge, 

 been found in the Coral Eag. Thus it must be regarded as an 

 Upper Oxfordian fossil, whose representatives should be sought in 

 such beds as the " Oolithe ferrugineuse " rather than in the " Coral 

 Eag " of the Continent. 



58. — Cylindkites, sp. Plate IV. Fig. 9. 

 The specimen figured is from the Coral Eag of Ayton. It 

 represents a form which is of somewhat rare occurrence in the Coral 

 Eag of the Scarborough district. The examples hitherto found are 

 too imperfect to identifj'- or describe. The nearest species is pro- 

 bably Cylindrites Lhuidii, Whiteaves. It belongs to the section of 

 Cylindrites with a well-developed spire, whereas Cy. elongatus 

 belongs, as we have seen, to the section where the spire is sunken. 

 EXPLANATION OF PLATE IV. 



Fig. la. Trochotoma iornatilis, Phillips. Coral Eag of Brompton. Strickland 



Collection. 

 ,, Ih. ,, „ Same Collection. C. R. North Grimstou. 



,, 2a. and J. P/ewroi'oOTana, species. Lower Limestones, "Wydale. My Collection. 



Front and back. 



