HuTTON. — The Geological History of Neio Zealand. 165 



next system. It is in the rocks of the Maitai system, in the 

 neighbourhood of tlie granites, that the gold reefs of Preser- 

 vation Inlet and the Inangahua occur. 



*&■■ 



Hokanui System. 



The next system is better developed in the Hokanui 

 Mountains of Southland than elsewhere, and so it has been 

 called the "Hokanui system.-" In the southern part of Otago 

 it covers a considerable amount of country, from the Living- 

 stone Mountains to the sea between the mouths of the Mataura 

 and Clutha Elvers, where it is between 20,000 ft. and 25,000 ft. 

 thick. In Canterbury it is known in many places, from Mount 

 Potts and the Malvern Hills to the Upper Wairau and Kai- 

 koura Mountains. It is also developed at Wairoa and Eich- 

 mond, near Nelson, but it is doubtful whether it exists on the 

 west coast of the South Island. 



In the North Island the Hokanui system occurs at Welling- 

 ton and along the eastern side of the Euahiue Mountains to 

 the Euakamara Mountains, near the East Cape, always lying 

 on the south-eastern side of the Maitai system. On the west 

 coast of the North Island it is found at Kawhia, Eaglan, and 

 Port Waikato, and here it lies on the north-western side of 

 the Maitais. This seems to show that the geanticlinal axis of 

 the South Island runs through the centre of the North Island 

 from Wanganui to the Bay of Plenty, although no Palaeozoic 

 rocks are visible, and it is not even a mountain-range, but 

 only a band of volcanic activity. 



There is, no doubt, a stratigraphical break between the 

 Hokanui and Maitai systems, but in no place is the former 

 seen to rest on rocks older than the Maitais, and the bound- 

 ary between the two systems is very difficult to draw. 



Near the junction of the Hokanuis with the Maitais thick 

 beds of greenstone-ash (known as the " Te Anau series") are 

 found, often accompanied by intrusive basic rocks, and it is 

 sometimes uncertain to which system they should be referred. 

 Indeed, they may belong to more than one geological horizon. 

 They are probably connected with the outbursts of basic and 

 ultra-basic eruptive rocks which are found from Bluff Hill in 

 Southland to Nelson. These rocks in the West Coast Sounds 

 are chiefly gabbros and diorites which have acquired a foliated 

 structure through pressure subsequent to their eruption ; and 

 the same kinds of rocks are found in the Upper BuUer and in 

 the Eiwaka Mountains, west of Blind Bay. Hurunui Peak, in 

 North Canterbury, is another dioritic volcano belonging to the 

 lower part of the Hokanui system. Ultra-basic rocks (peri- 

 dotites and serpentines) are found at intervals from Milford 

 Sound to D'Urville Island, and these also appear to belong to 

 the same period as the diorites. 



