BELEMNITES OF THE OXFORD CLAY. 



117 



the alveolar region, and reaches to its anterior edge, which is eniarginate in conseqnence, 

 while that of B. isulcatuH belongs to the posterior part, dies out on the same region, 

 and ceases nearly opposite the alveolar apex. The canaliculated axis occurs in some 

 examples of B. Bessinus of Stonesfield and in B. lateralis of Speeton, but I have not 

 yet seen it in any Liassic species. 



Belemnites perfoi'atus, Voltz (PI. VIII, fig. 2), from Cretaceous beds at Osterfeld, is 

 canaliculated for the whole length of the axis of the guard ; and specimens of B. quadratics 

 and B. mucronatus from the Chalk frequently show this peculiarity, or else a condition of 

 the central parts which suggests their easily acquiring it. 



Locality and distribution. Weymouth has yielded characteristic specimens of this 

 species from the Oxford Clay, but they seem not to be plentiful there. I found only two 

 or three fragments in the clay on the shore north of Weymouth, mixed wuth hundreds of 

 the young forms of a hastate Belemnite. It is not mentioned among the fossils of the 

 Oxford scries known to Smith, who figures and describes the longer Belemnite known at 

 Chip|)enhani as B. Oioenii. About Oxford we find it rather frequently, especially towards 

 the middle and lower part of the clay deposit, with Ammonites Buncani, while in the 

 upper part B. Oicenii and B. excentricus occur more frequently, with Ammonites vertehralis. 

 The young forms are very rare in these parts. Near St. Neot's, again, they occur with 

 Ammonites Dnncajii, but not plentifully, as I find by Mr. Walker's communications, and 

 again near Peterborough, as I learn from Mr. Leeds. I doubt the occurrence of the 

 species in Yorkshire, and regard the mention of it in the first edition of my work on the 

 geology of that county (1829) as requiring confirmation. 



The locality of D'Orbigny's fossil is thus noticed : — " Elle a etc recueillce par 

 M. Tesson dans les marnes Oxfordiennes des Vaches-Noires (Calvados) ; elle parait y 

 etre rare." 



On a Group of Belemnites allied to Belemnites Pvzosianus of D'Orbigny. 



In ISIG William Smith figured, in his 'Strata Identified,' on the plate of Oxford 

 [Clunch] Clay fossils, a long subcylindrical Belemnite from Dudgrove Farm, in "Wilts. 

 In his ' Stratigraphical System' (IS 17) the fossil is described as "large, squarish, quickly 

 tapering to the apex ; diameter one inch at the largest end, length four or five inches.'' 

 The figure referred to represents the guard almost complete, with the alveolar cavity 

 exposed. I remember the specimen, which is now in the British Museum. Some years 

 later the species was recognised by my great relative in a fossil of the Kelloway Rock 

 in Yorkshire, to which I gave the name of B. tornatilis. Of this I had seen 

 specimens when the first edition of my work on the ' Geology of Yorkshire' was published 

 (1829), and described the fossil as elongated. In the second edition it was named, 

 with an equally brief description, but no figure (1S35). In 1841 the rich deposit of 



