484 Transactions, — Geology. 



water-worn character of the gold, and were it not that the conglomerates 

 above mentioned are of Paleozoic age I should consider that it exists in the 

 said conglomerates as an alluvial gold. 



Art. LXXVI. — On the Belemnites found in New Zealand. 



By Dr. Hectoe, C.M.G., F.E.S., Director of the Geological Survey. 



Plates XXII., XXIII. 



[Read before the Wellington Philosophical Society, IWi January, 1878.] 



Notwithstanding that our knowledge of the true nature and function in the 

 animal economy of the singular fossils comprised in the group BelemnitidcB 

 is very imperfect, then- importance as indicating particular zones in the 

 life-development of successive epochs has been fully recognized. That they 

 were the internal supports of soft-bodied molluscs allied to the Sepia of the 

 present day is certain, but there is no organ strictly analogous to them to 

 be found in the structure of any living form of cephalopod. We are there- 

 fore ignorant of the extent to which the variations in form in the fossil 

 belemnites were dependent on or correlated with important modifications in 

 the structure of the complete animal. Nevertheless these varieties are very 

 constant and characteristic of the particular geological formations in which 

 they are found, so that they afford most valuable indications to the strati- 

 graphist. 



The Belemnitidce first appear in the liassic period, and survive to the 

 close of the cretaceous period. They are divided into two genera — Belem- 

 nitella, which is confined to the chalk or upper cretaceous formations, and 

 Belemnites, which, with the exception of a single species (in England at 

 least), is confined to the formations below the chalk. 



No representative of Belemnitella, which is distinguished by a ventral 

 fissure of the guard and external vascular impressions, has yet been dis- 

 covered in New Zealand, so that in the following notes attention is confined 

 to the genus Belemnites. 



In order to facilitate the comparison of our belemnites with those des- 

 cribed from other countries I reproduce the grouping of the species adopted 

 by Phillips, Mayer, and other writers on the subject, modifying it to 

 comprise the New Zealand forms. 



1. AccELi. — Club-shaped and laterally compressed, without dorsal or 

 ventral grooves, but with lateral furrows. (Liassic.) 



2. Gastrocceli. — Cylindi-ical with a distinct ventral groove. (Jurassic.) 



