122 



BRITISH BELEMNITES. 



Belemnites spicuLARis, 11. s. Pi. XXXVIII, fig. 82. 



Guard. Cylindrical (hastate when young), tapering evenly to a point, much com- 

 j)ressed to an oval section, with a faint ventral groove drawn from the apex through 

 two fifths of the length of the axis ; a few striae about the apex, especially on the dorsal 

 asi)ect. 



Transverse section oval, the ventral face broader than the dorsal. Substance varied 

 by bands of brown (sepia-tint) and honey-yellow spar. 



Greatest length observed 10 inches, greatest diameter I hich. Shortest specimen 1 inch 

 long ; it is of the form PI. XXXIII, fig. 82 



Proportions (old). Taking the diameter at the aveolar apex at 100, the diameter from 

 side to side is 90 +, the axis 1000; the excentricity of the axis variable, in some speci- 

 mens small, in others the ventral radius = 40, the dorsal 60. 



Phragmocone. Incompletely known. The section is elliptical, within a ring of the 

 guard-fibres everywhere of nearly equal thickness ; the phragmocone section more elliptical, 

 therefore, than the section of the guard. The angle in one of Lieut. Patterson's specimens 

 appeared to be 18° at the apex, 15° in a more advanced part of the shell. The apex of 

 this phragmocone was placed at about one third of the diameter from the ventral margin. 



Locality. Eathie Burn, and Shandwick, on the coast of Cromarty : collected in great 

 abundance and in excellent condition by Lieut. Patterson, who gave me much informa- 

 tion as to the circumstances under which he obtained the specimens and the accom- 

 l)anying fossils. He further assisted my researches by presenting to me a set of 

 photographic representations of much interest. 



The fossiliferous strata of the Mesozoic system on this coast have been usually described 

 as Liassic, and on a first view of the shale and these Belemnitic fossils such an opinion 

 might be readily adopted. The Belemnite now in question has analogy to some of the 

 long species of the Upper Lias, such as B. tripartitus, while the next to be mentioned 

 seems to revive the memory of B. longissimus of Miller. Their affonity, however, is with 

 the long species of the Oxonian stage in the Oolitic system. Among the accompanying 

 fossils I observed in Lieut. Patterson's collection Gryphma dilatafa, large and small ; 

 Perna ; Avicula Braamburiensis ; Pleurotomaria ; Aiimonites resembling, if not identical 

 with, A. vertebralis, Sow., A. excavaius, Sow., A. flcxicostatus, Phil., A. plicatilis, Sow., 

 A. Gowerianus, Sow., A. bijAex, Sow ; scales of Lepidosfeus ; cervical vertebrae of 

 fcldhyosaurus. The Belemnites form a bed in the shale. 



Observations. It is difficult to fix upon any definite characters by which to distin- 

 guish this Belemnite from B. Oweiiii, except the greater proportionate length of the axis 

 and the faintness of the apici-ventral groove. The slight striae about the apex are only 

 seen on one or two specimens. 



