BELEMNITES OF THE LIAS. 



55 



Grenoble. Similar, also, are some Belemnites discovered by Mr, C. Moore at Camerton, 

 in the "Bucklandian beds" of Lower Lias, of which it seems proper to add the provisional 

 description which follows; though, until further specimens come to hand, sufficient 

 figures and sections cannot be given. 



Belemnites grand^vus, n. s. 



Guard. Slender, cylindrical, gradually tapering to a produced (bent) point; no 

 groove on any part, but the sides somewhat flattened with age ; section nearly round in 

 the young specimen, a little compressed when older. 



Dimensions. Of the two specimens, one, the younger, is 3" 1 25 inches long ; the other, 

 older, only 2-5, probably a deformed specimen. 



Proportions. The longest diameter at the apex of the phragmocone being taken 

 at 100, the ventral part of it is 43, the dorsal 57 ; the apicial line 500 in the young 

 specimen, but in the old specimen 300. 



Locality. Lower Lias, " Bucklandian beds," Camerton, Somerset {Moore). The 

 specimens are reddened by oxidation of iron. 



Observations. Both specimens are bent towards the point a little irregularly, that is, 

 obKquely to the general dorso-ventral plane of symmetry. The younger specimen has 

 a produced striated apex ; in the older one this part is contracted and irregularly pli- 

 cated, with a sort of umbilicus. The surface is in parts eroded, so as to show the 

 curiously undulated plications of the formative membrane. In early age the guard was 

 depressed, when full grown compressed ; these variations depend on the thicknesses of 

 the successive increments by laminae of growth. 



Belemnites pollex, Simpson. PI. IX, fig. 20. 



Reference. Belemnites pollex, Simpson, Yorkshire Lias, No. 18, p. 27, 1855. 



Guard. " Subcylindrical, short, one side rather flattened ; apex very obtuse, witli a 

 short irregular groove." " Length 3^ inches, width 1^ inch." 



Locality. Whitby, in Upper Lias, from the collection of the late Mr. Ripley 

 {Simpson). West of Staithes, from the upper part of the Lower Lias {Phillips). 



Observations. Of this remarkable form only two examples of the guard are known 

 to me — the large specimen in the Whitby Museum, represented in my sketch, PI. IX, 

 fig. 20, which was described by Simpson ; and the smaller one figured on the same plate, 

 which is in my cabinet. Simpson's description is given above. The short irregular 

 groove mentioned cannot be esteemed diagnostic. The diameter of the guard is almost 

 imperceptibly enlarged behind the alveolar region. The axis of the guard does not much 



