360 Transactions. — Geology. 



Art. XL. — Notes on the Geology of KnaotuiiiL Goldfield. 



By James Park, F.G.S., Lecturer, Thames School of 

 Mines. 



[Read before the Auckland Institute, 19th June, 1893.] 



It has often been asserted that the Hauraki Peninsula is a 

 goldfield from one end to the other, and the numerous dis- 

 coveries of the last few years would certainly seem to justify 

 this conclusion. The wide gaps which at one time existed 

 between the older-established goldfields are being gradually 

 filled up, while the boundaries of all the fields are being con- 

 tinually extended. 



Perhaps the most important find of late years was the dis- 

 covery of payable gold at Kuaotunu, a little over three years 

 ago. Since that date a large amount of money has been ex- 

 pended in the preliminary work of prospecting and opening 

 the mines, erection of batteries, and other necessary works, 

 and as a result this field has now taken its place as a steady 

 gold-producer. 



Kuaotunu is situated on the east-coast side of the penin- 

 sula, on the neck of the short peninsula lying between Mercury 

 Bay and Whangapoua Harbour. It is connected with Coro- 

 mandel by a bridle-track, and there is regular communication 

 with Auckland by a steamer-service twice a week. The port 

 suffers the disadvantage of being an open roadstead ; and this 

 is a difficulty which it will be very costly to remedy. The 

 water-w^ay has, nevertheless, been an inestimable boon to the 

 place, and it is doubtful if without this it would have been able 

 to survive the troubles which beset the early stages of its 

 existence. 



General Geological Features. 



When first I examined this goldfield I was led, from the 

 surface indications, to the belief that its geology would be 

 found to present but little to distinguish it from the geology of 

 the Thames, Coromandel, and other well-known goldfields in 

 the Hauraki Peninsula. A detailed examination on a sub- 

 sequent occasion showed that, including the Matarangi 

 district, two distinct geological formations are represented on 

 this goldfield. Both contain gold-bearing quartz veins. The 

 younger formation consists of decomposed andesitic tuffs and 

 breccias, which do not occur within the drainage-area of the 

 Kuaotunu Eiver, but are largely developed at Matarangi, 

 whence they extend almost continuously to Coromandel to the 

 west, and Mercury Bay and Makarau to the south. 



