66 



BRITISH BELEMNITES. 



Belemnites microstyltjs, n. s. PI. XIII, fig. 31. 



Guard. Very slender, almost perfectly cylindrical in the post-alveolar region 

 till towards the apex, expanding over the conotheca with remarkable regularity. No 

 lateral groove. 



In young specimens the substance of the guard is transparent and solid toward the 

 point, mostly opaque, and more friable in a long space over and behind the alveolar 

 region, as in B. clavatus. 



Phragmocone. Straight, very regularly tapering at an angle of 18°, with septa 

 even or scarcely waved, and placed at distances somewhat greater than usual, viz., one 

 fifth of the diameter. 



Section of the phragmocone shghtly elhptical. 



Locality. One specimen. No. 349, in the Collection of the Geological Survey, Jermyn 

 Street (fig. 31, g), was discovered by Mr. Day in a nodule from the Belemnite-bed of 

 Lyme Regis. Another in the Oxford Museum (fig. 31, o) was presented by Mr. Murley 

 from the Insect-bed at Dumbleton. 



Belemnites longissimus. Miller. PI. XIII, fig. 32. 



Reference. Belemnites longissimus. Miller, ' Geol. Trans.,' 2nd series, vol. ii, p. 60, 

 pl. viii, figs. 1, 2 (Paper read AprH, 1823), 1826. 



Guard. Excessively elongate, compressed, with faint lateral grooves, and a blunt, 

 roughly striated apex. 



Phragmocone, Unknown. 



Locality. Lyme Regis. In the Collection of the Bristol Institution is a specimen 

 (No. 33) which may have served Miller in considering the species named B. longissimus. 

 Another in the same collection (No. 27), marked B. cylindricus, Blainville, may be 

 identical. I have a few examples from the Belemnite-bed under Golden Cliff, but none 

 of these specimens arc sufficient for good description. A Belemnite of the same general 

 form, and even longer in proportion when young, occurs in shales of the Croraartic 

 Coast, which have been called " Lias " by geologists. They, however, contain only fossils 

 of the Oxford Clay and Coralline Oolite series, and the Belemnite has a difiercnt shape 

 when old. 



