176 
The N.Z. Journal of Science and Technology. 
[May 
likely to be obtained. Some years ago burnt lime was produced from this 
belt of marble, the kiln being situated on the northern side of the Riwaka. 
Apparently the belt in this locality is about half a mile in width. 
Dark-coloured marble outcrops for over a mile along the main Takaka 
Valley Road about ten miles from the Takaka Wharf. Many shades of 
grey are represented, as well as stone beautifully veined with white, but 
marble of a dead-black colour was not seen. The rock is fine-grained, and 
a little pyrite seems usually to be present. Blocks of the same size as 
those at the Ngarua Quarry cannot be obtained, but the jointing is of such 
a nature that when a face has been opened blocks up to 3 ft. cube will 
probably be readily quarried. 
I had an opportunity of seeing the cutting and polishing plant of the 
Nelson Marble Company. This is situated close to the Motueka Wharf, 
and comprises a breaking-down saw, carborundum smoothing-wheels, and 
pneumatic chisels. A suction-gas plant is in course of erection to supersede 
the steam-engine supplying power to a small air-compressor and the other 
machinery. 
Geology. 
The valley of the Riwaka and the mountains to the northward have been 
examined by several geologists, and a list of the published reports is given on 
page 86 of the Ninth Annual Report of the New Zealand Geological Survey, 
1915. The headwaters of the Riwaka are cut through the great belt of 
marble that stretches from the neighbourhood of Mount Arthur northward 
to Golden Bay. The lower valley has been excavated from a complex of 
rocks of which the sedimentary members range from quartzite, which may 
be micaceous, to greywacke and argillite, altered to hornfels and in places 
decidedly schistose. The igneous rocks present are a siliceous variety of 
granite and gabbro ; while a hornblende schist or gneiss, which is perhaps 
the gabbro metamorphosed by earth-movements, is also mentioned by 
several writers. Before the Riwaka leaves the hills the valley is crossed 
by a band of marble about 30 chains in width, which in the valley of Holy- 
oake Creek is said to swing westward and connect with the main zone of 
marble. 
A sample of marble taken from the waste rock produced in cutting 
building-blocks for Parliament House from the rough stone obtained from 
the Kairuru Quarry, Pikikiruna Range, was found by Dr. J. S. Maclaurin 
to have the following composition:— 
Silica (Si0 2 ) 
0-82 
Alumina and iron oxides (A1 2 0 3 , Fe 2 0 3 , FeO) 
0-11 
Lime (CaO)* . . . . 
.. 55-16 
Magnesia (MgO) 
0-47 
Potash (K 2 0) 
Nil 
Soda (Na 2 0) 
Nil 
Water at 100° C. 
0-08 
Phosphoric anhydride (P 2 0 5 ) 
0-04 
Carbonic anhydride (C0 2 ) 
. . 43-34 
Combined water and organic matter 
Nil 
100-02 
^Equivalent to CaC0 3 
.. 98-50 
The gabbro is everywhere deeply weathered. The sample collected 
was taken from a huge boulder that had to be removed from the road by 
blasting at a point about two miles up the south branch of the Riwaka. 
