III. — GEOLOGY 



Art. XL VII. — Notes on the Mineralogy of Neiv Zealand. 

 By S. Herbert Cox, F.C.S.,F.G.S., Assistant Geologist & Inspector of Mines. 



[Read before the Wellington Philosophical Society, 21st October, 1882.] 

 The following paper, which is in continuation of the one published in 

 last year's volume* of the "Transactions of the New Zealand Institute," 

 will be devoted to the non-metallic minerals. 



Non-Metallic Minerals. — Class I. 

 Water. 



Water, H. — As a simple mineral this substance needs no comment, but, 

 as pointed out by Dr. Hector (Handbook of New Zealand for Melbourne 

 Exhibition, 1880, p. 102), New Zealand is singularly rich in springs of 

 water that hold mineral salts in solution, and some of these are already 

 noted for their valuable medicinal properties. 



Both hot and cold springs are found, the former being, with few excep- 

 tions, confined to the districts of the North Island where volcanic forces 

 have been active during the latest tertiary period, and are not yet altogether 

 dormant. A few thermal springs are found to escape from the upper 

 mesozoic rocks in localities where the source of heat can only be attributed 

 to chemical decomposition of bituminous matters and sulphides ; and, in 

 a few instances, warm waters spring from palaeozoic rock-formations in the 

 South Island. The cold mineral springs have a wider distribution, but 

 have only, as yet, been examined from comparatively few localities. The 

 mineral waters of New Zealand may be classified, from the analyses 

 that have been made in the Colonial Laboratory, into the following 

 groups : — 



Saline. — Containing chiefly chloride of sodium. 



Alkaline. — Containing carbonates and bicarbonates of soda and pot- 

 ash. 



Alkaline siliceous. — Waters containing much silicic acid, but changing 

 rapidly on exposure to the atmosphere and becoming alkaline. 



Hepatic or sulphurous. — Waters, the prominent character of which is the 

 presence of sulphuretted hydrogen and sulphurous acid. 



Acidic. — Waters in which there is an excess of mineral acids, such as 

 hydrochloric and sulphuric acid. 



* Trans. N.Z. Inst., vol. xiv., p. 418. 



