392 Transactions. — Geolorj;/. 



wollastonite passing into scapolite by substitution of alumina for lime. It 

 is a green-coloured mineral, quite amorphous, and occurs coating one side 

 of a tough light green rock, probably jade. 



CJir)/solite(Olivine),(M.g,'FeY Si. — The first mention of the occurrence of 

 this mineral in New Zealand is by Dr. Hector (Jurors' Kep. N.Z. Ex., 1865, 

 pp. 266, 418, and 437), who states that it is of frequent occurrence in the 

 basaltic rocks of Saddle Hill and elsewhere, and also occurs in Milford 

 Sound. It is again mentioned by Dr. v. Haast (Jurors' Eep. N.Z. Ex., 

 18G5, p. 257) as grains in the basaltic rocks of Banks Peninsula, and 

 (Trans. N.Z. Inst., vol. i., p. 180) as large concretions in basaltic rocks 

 from the Chatham Islands, and (Geol. Kep., 1870-71, p. 29) in the basalts 

 of the Hurunui and Mandamus districts. E. Daintree, Esq., F.G.S., refers 

 to its occurrence in dolerites from the Selwyn Kiver, Snowy Peak Eange, 

 Flagstaff Hill basin, and Hororata district, (Trans. N.Z. Inst., vol. vii., p. 

 458) ; Professor Liversidge also describes a specimen from Dunedin as 

 brown-coloured imbedded grains (Trans. N.Z. Inst., vol. x., p. 497), and I 

 have noticed small grains of this mineral, green and brown in colour, in 

 many microscopic sections of basaltic and doleritic rocks from various 

 localities. 



Dunite. — This mineral is a massive variety of olivine through which 

 grains of chromite are scattered. A specimen from the Dun Mountain, 

 Nelson, was first described by Dr. v. Hochstetter (New Zealand, 1863, Eng. 

 ed., p. 474) as follows : — " It consists of a very peculiar kind of rock, of a 

 yellowish-green colour when recently broken, but turning a rusty brown on 

 the surface when decomposing. The mass of the rock is olivine, containing 

 fine black grains of chromate of iron interspersed ; it is distinguished from 

 serpentine, for which it was formerly taken, especially by its greater hard- 

 ness and its crystalline structure. I have called it Dunite." Analysis of 

 dunite by E. Eeuter (Lab. of the Polyt. Inst, of Vienna) : — 



Silica 



42-80 



Magnesia 



47-38 



Protoxide of iron 



9-40 



Water . . 



•57 



Sp. gr. . . 3-30 



100-15 

 It is again mentioned by Dr. Hector (Jurors' Eep. N.Z. Ex., 1865, p. 411), 

 who adds to Dr. v. Hochstetter's description, that it possesses a flaky 

 structure, conchoidal fracture and hardness of 6 ; and he also mentions its 

 occurrence at Milford Sound, where it passes into jade. He again alludes 

 to it (Trans. N.Z. Inst., vol. ii., p. 377), stating that at the Dun Mountain 

 it appears at the surface as a large mass several miles in extent. It has 

 since been discovered at Jackson's Bay, by Mr. D. Macfarlane, associated 

 with serpentinous rocks (Geol. Eep., 1876-77, p. 27). 



