396 Transactions. — Geology. 



Mount Potts and Clent Hills beds, the Director of the Geolo- 

 gical Survey says, " The Mount Potts beds, besides an abund- 

 ance of Brachiopoda, abound in reptilian remains, the true 

 character of which has not yet been exactly determined, but 

 from the nature of the vertebrae it would appear that these 

 remains have some affinity to the genus Ichthyosaums."'-^' 

 Then follow some details of the saurian remains found by 

 Mr. McKay in 1877. The Director continues, " The vertebrae 

 are much restricted in length, and the ribs flattened and 

 hatchet-shaped, but not divided at the articulation. Some of 

 the vertebrge are of enormous size, as much as 15 in. in dia- 

 meter. One fine specimen not yet collected shows a con- 

 vected series of sixteen vertebrte and thirty-two ribs of the 

 character described. The centra of the vertebrse are ii-in. in 

 diameter, and the ribs are 3ft. Gin. in length." 



The above conveys the impression that Sir James Hector 

 entertained some doubts of his previous identification of Ich- 

 thyosaurus. In 1879 he so far modifies his opinion as to 

 refer the remains to the genus Eosatirus of Marsh. f 



So far as I could judge from the fragments of bone I saw 

 and collected, I was of the opinion that at least two different 

 genera of saurians were represented in the Eocky Gully bone 

 bed. 



The Mount Potts plant beds, which are acknowledged by 

 Sir Julius von Haast and Mi-. McKay to underlie the shell 

 and bone beds at Eocky Gully, contain a flora which Ettings- 

 hausen described as being Triassic and Professor McCoy as 

 Jurassic. I 



On the other hand. Professor McCoy is credited with hav- 

 ing referred the exuvia of the shell beds, which appear to 

 overlie the plant beds, to the Upper Devonian or Lower 

 Carboniferous period. § 



It should be mentioned, however, that Professor McCoy, 

 in a memorandum to Sir James Hector dated the 12th 

 August, 1885, distinctly denies that he had " heard of saurian 

 bones mingled with Cai-boniferous shells in Mount Potts beds 

 in New Zealand, and had not determined them." He admits, 

 however, that he did make determinations of Carboniferous 

 limestone Mollnsca and Echhwdermata submitted to him by 

 Dr. Von Haast from Fossil Creek, Clyde, Eangitata, Southern 

 Alps, and says that he has " no reason to doubt the age sug- 

 gested for those beds as above." || 



That a saurian-bone bed does occur at the close of the 



• Reps. Geol. Expl., 1890-91, p. 147. 

 t Reps. Geol. Expl., 1878-79, p. 11. 

 \ Trans. N.Z. Inst., vol. xvii., p. 333. 

 § Loc. cit., p. 333. 

 II Reps. Geol. Expl., 1885, p. xxi. 



