290 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 18, 



allied to the Belemnite, — De la Beche's determination having* been 

 founded, as his figure shows, upon a very imperfect specimen. Allied 

 though it be to the Belemnite, yet I think that it must be looked 

 upon as generically different, since it not only differs in the out- 

 ward form, but also in the internal structure of the guard. The 

 very elongated proportions of the phragmacone also differ from any 

 that I have seen associated with true Belemnites*. 



In these layers of shale there are also considerable numbers of 

 Rhyncholites, which are assigned by local collectors to the animal of 

 the Belemnite. As they differ considerably from those of the Nau- 

 tilus found in the Lower Lias, I am inclined to think that the local 

 assignment of these to the dibranchiate Cephalopods may be correct ; 

 but more evidence is required upon this point. 



Associated with the above remains occur very many Ammonites 

 and Nautili. Amongst the former are large and crushed specimens 

 of A. fimhriatus, Sow., old and young specimens of A. Bechei, Sow., 

 and occasionally one of A. Loscombii, Sow. ; this is likewise the chief 

 horizon of A. Henleyi, Sow., which however occurs also in the over- 

 lying marls. Many forms of small pyritized Ammonites are found 

 in these beds, and several species of Nautilus are also to be met with 

 herein. 



Gasteropodous shells are common, the most frequent species being 

 the TrochusOaudryanus, D'Orb., and Pleurotomaria expansa, Sow. sp. 

 Amongst the Conchifera, Crenatula ventricosa and Nucula variabilis (?) 

 are the most abundant forms. Brachiopoda are likewise abundant, 

 but so crushed and deformed as to render identification difficult. 

 Upon a specimen of Ammonites Henleyi in my possession, from these 

 beds, there is a numerous colony of very small Cranial ; and in several 

 other instances I have observed the same form upon fragments of 

 the same species of Ammonite, as likewise upon a specimen of Am- 

 monites Bechei from the beds above. 



Of the Vertebrata, good specimens of both Saurians and Pish have, 

 I am told, been obtained from these beds, though I have been un- 

 able to find any authentic specimens. The Saurian of which bones 

 are most frequently found is the Ichthyosaurus tenuirostris, Conyb. ; 

 /. communis, Conyb., also occurs. Both of these species are like- 

 wise met with far down in the Lower Lias. 



Of Fish, I have seen fragments of the genus JEchmodus from these 

 beds. 



Pentacrinus basaltiformis, Miller. 



Terebratula numismalis, Lam. 



Rhynchonella. 



Craniae, upon Ammonites Henleyi. 



Crenatula ventricosa, Sow. 



Hinnites velatus, Goldf. 



Plicatula spinosa, Sow. 



Pecten, several species. 



Cuculloea. 



Nucula variabilis (?), Sow. 



Pleurotomaria anglica, Sow. 



expansa, Sow. 



* Since writing the above, I have been fortunate enough to obtain the pen of 

 the creature, associated with the phragmacone and guard. This not only fully 

 corroborates my supposition that the animal was generically different from the 

 Belemnite, but presents us with an unknown and extraordinary modification of 

 pen-structure, which Professor Huxley has kindly undertaken to explain in a 

 description of the new fossil. 



