1918.] The N.Z. Journal of Science and Technology. 
371 
On the 2nd September, 1873, Dr. Hector, Director of Geological Survey, 
reported the result of a visit to the Collingwood Coal-mine.* He gives a 
detailed account of the various beds encountered in a drift which was then 
being driven to explore the coal-measures. At some distance in (260-6 ft.) 
coal 0-8 ft. thick, dipping 30° to the west, “ passes under a thick mass 
of dolomite of magnesia limestone [sic], passing into breccia of the same. 
Contains carbonate of lime, 53 per cent. ; carbonate of magnesia, 44 per 
cent.” Apparently the dolomite band as seen in the drift was not more 
than 7J ft. thick, and may have been less. 
In 1915 a sample of dolomitic limestone, which it is understood came 
from a stream-bed within or near the old Collingwood Coal-mining Com¬ 
pany’s lease, was analysed at the Dominion Laboratory, with the following 
result: — 
Silica (Si0 2 ) 
0-57 
Alumina and iron oxide (ALCL, Fe 2 0A 
0-32 
Lime (CaO) 
.. 32-21 
Magnesia (MgO) 
.. 19-92 
Alkalies (Na 2 0, K 2 0) 
0-06 
Carbonic anhydride (C0 2 ) 
.. 46-92 
100-00 
A band of crystalline limestone or marble occurs on the eastern side of 
the old Collingwood Coal-mining Company’s lease, and the prospecting of 
this for dolomite may be recommended. 
An analysis of dolomitic limestone from Rolling River, a tributary of 
the Wangapeka, is reported by Skey in the Twentieth Annual Report of the 
Colonial Museum and Laboratory , 1886, page 42. Skey states,— 
“No. 3940 is a graphitic dolomite from the Rolling River, forwarded 
by Messrs. Fifield. Its precise composition is as follows :— 
“ Carbonate of lime . . . .. 62-31 
Carbonate of magnesia ,.. .. .. 32-18 
Alumina and iron oxides . . .. .. .. 2-27 
Silica .. ., .. .. .. .. 2-92 
Graphite .. .. .. .. . . 0-32 
100-00 ” 
Presumably this rock came from the Silurian or Ordovician limestone of 
Mount Owen, the northern slope of which is drained by the Rolling River 
and its tributaries. 
There is a fair probability that a workable deposit of dolomite will be 
found somewhere in connection with the Palaeozoic limestones of Nelson. 
So far, no serious search for magnesian carbonates has been made out¬ 
side the Parapara district. 
The following analyses of serpentine, irregularly streaked with bands 
of white carbonate, are of great interest. The samples analysed were from 
* This report will be found, under the heading of “ The Coalfields of New Zealand 
(Report on),” in Pari. Paper E-10, 1873, pp. 27-28. It is reprinted in a publication 
printed in 1879 by Wyman and Sons, London, for the New Zealand Government. This 
brochure has the title, “ 100,000 Tons of Steel Rails required to be manufactured in 
New Zealand. Iron and Coal. Reports on the Mineral Deposits of the Colony, addressed 
to the Hon. the Minister for Public Works, and published by Order of the Government. 
With Maps and Plans.” 
