400 



Transactions. — Geology. 



specimen from Whakahara, on the Wairoa Eiver, Auckland, where it occurs 

 in a vein running through certain tufaceous beds in the Whakahara Saddle, 

 between Mauugarahu and Tokatoka. The crystals are long slender rhombic 

 prisms, ooP with pyramidal ends P. 



Chabasite, Jy. Si 8 + Ca (Na, K) Si + 6 H, is mentioned by Dr. 

 Hector in vesicular basalts near Dunedin (Jurors' Eep. N.Z. Ex., 1865, 

 p. 267), and by Dr. v. Haast in the trachyte of Banks Peninsula (Jurors' 

 Eep. N.Z. Ex., 1865, p. 257; there is also in the Catalogue of the Otago 

 Museum a mention of a specimen from Helenburn. The specimens in 

 the collection of the Colonial Museum are all from the first-named locality, 

 and they consist of small rhombohedral crystals in cavities in the basaltic 

 rocks. B.B. it deflagrates slightly and fuses to a porous enamel; colour 

 brownish- white, no soda reaction visible. 



Gmelinite, j£ Si 3 + Na (Ca, K) Si + 6 H, is mentioned by Dr. 

 Hector in vesicular basalts near Dunedin (Jurors' Eep. N.Z. Ex., 1865, 

 p. 267). Specimens from this locality in the collection of the Colonial 

 Museum are pure white, small hexagonal pyramids with OP ends. B.B. 

 gives faint soda reaction only. 



Silicates of Alumina, hydrous and anhydrous. 



Kaolin, -41 Si 2 + 2 H, is mentioned by Dr. Hector at the Manuherikia 

 Plains and Arrow Eiver (Jurors' Eep. N.Z. Ex., 1865, pp. 267, 438), and 

 at the Whau, Auckland (Jurors' Eep. N.Z. Ex., 1865, p. 35) ; and I have 

 mentioned its occurrence at Mt. Somers, Canterbury (G-eol. Eep., 1876-77, 

 p. 6), where it is formed by the decomposition of felsite porphyries. Speci- 

 mens from drift at Collingwood have also been forwarded to the Museum. 



Clay. — All the varieties of clay are found in the colony, but, for a de- 

 tailed description of these with their analyses, I must refer the reader to 

 the " Manual of the Mineral Eesources of New Zealand," by Dr. Hector, 

 in course of publication. A very fine sample of pipeclay occurs at 

 Hakateramea, Canterbury. 



Bole occurs as nests in the doleritic rocks passed through in the Lyttel- 

 ton tunnel, and is associated with crystals of magnetite. Its specific 

 gravity is 2-089, and composition as follows : — 



Silica 44-78 



Alumina . . . . : 



. . 15-66 



Iron 



. . 16-87 



Manganese 



•60 



Lime 



2-02 



Magnesia 



5-02 



Potash 



2-69 



Water of constitution 



12-36 



100-00 



