1918.] The N.Z. Journal of Science and Technology 369 
Dolomite occurs at Thames (variety pearl-spar) in some of the quartz 
lodes, at the Malvern Hills, Canterbury, and to a greater or less extent 
in the altered ultra-basic rocks (serpentine, &c.) of Nelson, Westland, and 
western Otago. Magnesian or dolomitic limestone occurs in the Waitomo, 
Gisborne, Taranaki (in concretions), Parapara, Collingwood, Little Wanganui 
(Karamea), Rolling River, and Oamaru districts. At Hyde, Central Otago, 
an impure dolomitic clayey-looking substance has been found. Of these 
occurrences those of most importance at the present time appear to be the 
ferriferous magnesian limestone or marble near Parapara and the dolomite 
near the old Collingwood Coal-mine. 
Geological Survey Bulletin No . 3 —“ The Geology of the Parapara Sub¬ 
division, Karamea, Nelson ” (1907), by J. M. Bell, E. de C. Clarke, and 
E. J. H. Webb—has little to say about the dolomitic rocks of the Parapara 
district. On page 38 an analysis of cherty rusty carbonate from Parapara 
Gorge with 12-48 per cent, of magnesia (MgO) is given, and the remark is 
made that some of the carbonate rocks of the district contain so much 
magnesia as to approach dolomite. In 1913 Mr. F. G. Gibbs, of Nelson, 
forwarded several samples of magnesian rock from Parapara to Mr. F. Reed, 
Inspecting Engineer, Mines Department. These were analysed (Nos. 2-4 
below), but none was sufficiently pure to be of value for lining steel-furnaces. 
Mr. J. Bassett, of Parapara, on request then forwarded five further samples, 
two of which, on analysis, were found to be fairly low in silica. The various 
analyses are as follows :— 
1. 
2. 
3. 
4. 
Silica (Si0 2 ) 
24-70 
8-83 
35-14 
30-60 
Alumina (A1 2 0 3 ) 
0-96 
0-24 
0-85 
0-41 
Ferric oxide (Fe 2 0 3 ) 
0-32 
5-76 
6-32 
5-36 
Ferrous oxide (FeO) 
6-55 
, . 
• « 
• « 
Manganous oxide (MnO) 
0-28 
. . 
. . 
• • 
Lime (CaO) 
22-45 
26-97 
0-07 
20-53 
Magnesia (MgO) 
12-48 
16-65 
40-33 
12-31 
Carbonic anhydride (C0 2 ) 
32-20 
41 -56 
17-48 
31-08 
Phosphoric anhydride (P 2 CG 
. . 
0-06 
0-05 
0-05 
Sulphur trioxide (S0 3 ) 
• • 
0-10 
0-14 
0-17 
Loss on ignition 
0-15 
, * 
. . 
. „ 
Moisture at 100° C. . . 
0-08 
0-07 
0-03 
100-09 
100-25 
100-45 
100-54 
No. 1 also contains titanium dioxide (Ti0 2 ), 0-02 
per cent. 
5 . 
6. 
7. 
8. 
9. 
Silica (Si0 2 ) 
11-72 
17-70 
20-13 
3-22 
1-50 
Alumina (A1 2 0 3 ).. 
0-54 
0-19 
0-21 
0-33 
0-83 
Iron oxide (Fe 2 0 3 ) 
8-20 
7-88 
7-24 
8-92 
11-32 
Lime (CaO) 
33-44 
27-85 
30-75 
34-39 
32-62 
Magnesia (MgO) .. 
9-87 
11-23 
12-98 
10-21 
11-21 
Carbonic anhydride (C0 2 ). . 
34-22 
34-65 
28-42 
41-99 
41-86 
Water and organic matter. . 
1-76 
0-16 
0-14 
0-79 
0-18 
Undetermined 
0-25 
0-34 
0-13 
0-15 
0-48 
100-00 
100-00 
100-00 
100-00 
100-00 
24—Science. 
