410 Transactions. — Geology . 



Description. — Ehombic, in radiating groups, which separate in thin 

 flexible lamina?. Hardness 2 to 2-5 ; colour, whitish green to dark green, 

 weathering to a bronze hue and pearly lustre. B.B. infusible, but becomes 

 white ; odour, bitter argillaceous when breathed upon. Allied to picros- 

 mine and antigorite. It is from the Dun Mountain, where it occurs with 

 the serpentine rocks. It was collected by the late Mr. E. H. Davis. 



Akt. XLIX. — -Descriptions of some new Tertiary Shells from Wanpanui. 

 By Professor F. W. Hutton. 

 [Read before the Philosophical Institute of Canterbury, 1th September, 1882.] 

 A short time ago a collection of over a hundred species of Mollusca from 

 the Wangauui bed was submitted to me for determination by Mr. S. H. 

 Drew, of Wanganui, and in it I found the following forms which appear to 

 be undescribed : — 



Trophon expansus, sp. nov. 



Shell ovate ; spire moderate, acute : whorls five or six, spirally grooved, 

 the grooves narrower than the ribs, about 26 grooves on the body-whorl, 

 crossed by undulating lamina? of growth worn smooth. Aperture ovate, 

 wide, slightly angled behind ; outer lip expanded ; columella rounded, with 

 a small posterior canal : anterior canal very short and recurved. 



Length, *77 inch ; breadth, -4 inch. Length of spire, -3 ; of aperture, 

 •85 ; of canal, *12 inch. 



This is one of the purpnroid Trophons, but with a rounded columella ; 

 it is so like the figure of Purpura patens, H. and J., that I should have con- 

 sidered it the same, but that the authors state that P. patens has the colu- 

 mella very fiat. 



Cominella drewi, sp. nov. 



Shell ovate, spire short : whorls six, spirally lirate, about 22 lira? on the 

 body-whorl ; the spire-whorls finely longitudinally plicate. Aperture ovate, 

 the posterior canal well marked : columella obliquely truncated ; anterior 

 canal well defined. 



Length, "78 inch ; breadth, *45 inch. 



This species is distinguished from all our other species of Cominella, 

 except C. ordinalis, Hutton, by being spirally lirate, and from this species 

 it is separated by its well-marked anterior canals, which makes it inter- 

 mediate between Cominella and Euthria. 



