GEOLOGY OF NEW ZEALAND. 439 
_ forms the chief part of the main range from Wellington to East Cape 
(Rimutaka series), as well as most of the outcrops of old sedimentary 
rocks in the Province of Auckland. The rocks are chiefly argillites, 
red and black slates, gray and green sandstones, with occasional beds of 
limestone in the South Island. Thick masses of greenstone tuff (ash) 
are found interbedded with the slates and sandstones in Otago and near 
Nelson, and in places in the North Island; but these rocks appear to be 
local only. The thickness is estimated by Dr. Hector at from 7,000 
to 10,000 feet, but it is very difficult to form an opinion, as the 
stratification is often obscure. 
That an unconformity exists between this and the Takaka systems 
is evident. In Nelson 1t rests indifferently on the Aorere and Mt. 
Arthur series, the Baton River series being absent. At the Tapanui 
Mountains, in Otago, the system rests partly on the Wanaka and partly 
on the Kakanui series, evidently shewing an unconformity. In the 
West Coast Sounds it appears to rest upon the Manipouri system. In 
consequence of the rocks being generally unfossiliferous, it has not yet 
been found possible to break this system up into distinct series. 
The Rimutaka series of the main range of the North Island no 
doubt belongs to the Maitai system. The Te Anau series of Dr. Hector 
is now considered by the Geological Survey to form the base of the 
Maitai system; but formerly it was thought to form the base of the 
Hokanui system. 
Remarkable beds of manganese ore generally associated with red 
jasperoid slates, are found in several places in the Auckland district, 
and again near Wellington. In many respects these rocks remind us 
of the deposits now being formed in the deeper parts of the Atlantic 
and Pacific Oceans. 
The Hokanuwi system is found in the South Island, on the eastern 
side of the geanticlinal outside the Maitai rocks, and also on the South- 
land synclinal from Catlin’s River to Mt. Hamilton. In Westland and 
north-west Nelson it is quite unknown. In the North Island it occurs 
between Kawhai and the Waikato, and again at Port Waikato. On 
the east side of the main anticlinal axis it occurs at Wellington in the 
Ruahine Range, and again in the Raukamara Range, near the East 
Cape. 
A small patch is found near Nelson (Wairoa series) ; but the two 
largest areas of this system are on the north-east and on the south of 
the island. Commencing in the neighbourhood of Kaikoura Peninsula 
it skirts the main range to the Hanmer Plains, sending up to the north 
a long tongue towards the Wairau Gorge. To the south it reaches the 
Canterbury Plains, at the Gorge of the Ashley. It reappears in the 
Malvern Hills, and in the north branch of the Ashburton River, from 
_ whence it runs southward to the neighbourhood of Mt. Peel, extending 
inland, through the Clent Hills and Rangitata River as far as the 
junction of the Clyde and the Havelock. Another exposure of these 
rocks occurs somewhere near the Mackenzie Plains, for fossils belonging 
to the system have been found in boulders in the Waitaki, but the rocks 
have not yet been detected in situ. The southern development of the 
System is on the coast, between the Clutha and Mataura Rivers, 
passing inland through the Hokanui Mountains to beyond Mt. 
