no 



BRITISH BELEMNITES. 



which is not seldom absent from the section), four principal forms appear to have reached 

 maturity in the area of England, which may, for convenience, be termed ' HastatiJ 

 including B. Jiastatus of Blainville ; ' CanaliculatiJ including B. sulcatus of Miller ; 

 ' Tornatiles' including B. Puzosianus of D'Orbigny ; and * Excentrid^ including 

 B. abhreviatus of Miller. When we endeavour to trace the history of these several forms, 

 from the youngest examples, we experience in more than the usual degree the difficulty 

 of obtaining a series of all ages for any one of the species. 



However carefully we may collect, in many favourable localities, it is nearly impractic- 

 able to fill up all the terms of the series ; and though scores of young ones have been col- 

 lected by my own hands from different localities, it is only in a few instances, and by the 

 aid of my pupils, that I have succeeded in proving to my own satisfaction the real 

 progress of these several forms tow^ards maturity. Nor does the method of examination 

 by sections of the older individual succeed in this case so well as in some others, because 

 of the frequently very close textm-e of the sparry substance, and its more complete con- 

 densation into an amber-coloured mass, than is usual in the earlier deposits. For this 

 reason the form of the very young shell cannot always be even approximately known by 

 examining polished or natural sections. As far as can be judged from these sections, 

 however, there is reason to think that most of the Belemnites of the Oxford Clay began 

 life in a more or less hastate, or else lanceolate, shape ; and this seems to be confirmed 

 by the fact, as I believe it to be, that no very small specimen has ever been observed in 

 the Oxford Clay or Kelloway Rock in England, except in one of these shapes. Extending 

 our view to Scotland, we find a somew^hat different result. The Belemnites of the 

 Cromartie coast have been collected very successfully at Eathie and Shandwick by Lieut. 

 Patterson, of Ripon, to whom I am obliged for the sight of his fine series, and for 

 photographs of many specimens. 



Two s})ecies at least have there arrived at maturity ; one, a peculiar elongated spicular 

 Belemnite, whose guard sometimes reaches the length of ten inches, is found in Mr. 

 Patterson's series of all sizes down to one inch : it is only in this very small and very 

 slender specimen that any approach to a fusiform shape of the guard can be recognised, 

 and then only in a very slight degree. Another of these species makes an approach to 

 B. sulcatus of ]\Iiller, and is longitudinally grooved up to the point, at least in all the 

 smaller specimens (Shandwick).' There is nothing in the smallest of these at all com- 

 parable to the clavate forms common in the Oxford Clay of England, though a slightly 

 hastate shape can be recognised among them. The strata from which these Belemnites 

 come have been called Lias, but what Ammonites and Conchifera I have seen from them are 

 of the Oxonian type of life. 



Two of the four Oxonian groups have been already mentioned in the Badonian 



' In Lieut. Patterson's Collection is one specimen of a decidedly Liassic Belemnite of the group of 

 D. elongatus (Miller), which is placed among the Shandwick fossils. 



