472 Transactions. — Geology. 



material ; but [he says] I may here point out that on the east 

 coast of this country most distinct traces of elevation are to be 

 observed. Upon the road from Oamaru to Kakanui old marine 

 boulders are to be seen everywhere, and distinct shore-terraces 

 with deep erosion-furrows. They lie at a considerable height 

 above high-water mark, and sometimes one above the other."* 



Thus we see that the evidence in favour of the marine origin 

 of the silt fits in with that derived, quite independently, from the 

 structure of the Canterbury Plains, and the existence of raised 

 sea-beaches at Amuri Bluff and other places. This conclusion is 

 strengthened by the botanical evidence, as reported by Mr. T. 

 Kirk and Dr. Cockayne, of sea-shore plants occurring inland at 

 the base of the mountains. Sir Julius von Haast and Mr. Hard- 

 castle take too local a view of the deposit, and neither of them 

 examined it at Oamaru or in Southland. On the whole we may 

 consider it as fairly well proved that the alluvial beds forming 

 the Canterbury Plains were formed when the land stood con- 

 siderably higher than at present, but was subsiding. The sink- 

 ing continued until the land was perhaps nearly 1,000 ft. lower 

 than now, when the silt-deposit was laid down, and then began 

 to rise again. 



Art. LI. — Three Neiv Tertiary Sliells. 



By Captain F. W. Hutton, F.K.S. 



[Read before the Philosophical Institute of Canterbury, 3rd August, l')04.'\ 



Plate XLIV. 



Pleurotoma hamiltoni. XLIV., fig. 1. 



Shell elongato-fusiform, large, aperture occupying nearly 

 half the length of the shell. No longitudinal ornamentation ; 

 whorls keeled. Spire long and sharp, of 10-11 whorls, the 

 whorls shouldered, and ornamented below the shoulder with 

 fine spiral striae, more distinct in the upper than in the lower 

 whorls. The shoulder of the upper 8 whorls with small 

 tubercles, about 12 in a whorl. Suture with a row of raised 

 points formed by the growth-lines. Spirals below the sinus 

 6 on the 7th whorl, 12 on the 9th whorl. Body- whorl nearly 

 smooth, the spiral striae being obsolete or altogether absent. 

 Aperture narrow with a well-marked posterior, wide sinus, 

 not very deep, rather broad, and not separated from the 

 suture. Anterior canal long and straight. 



•Zeitschr. (1. Dents. 1> •_< olnl. U-sellsrhaft, I". 17"' 



