1919.] 
Departmental Reports. 
119 
a number of manganese deposits which will be found of value when steel- 
making, glassmaking, and other industries requiring manganese have been 
established in the Dominion itself. 
CLAY AND FULLERS’ EARTH. 
During the past year the Geological Survey has given further attention 
to the subjects of clays for pottery and firebricks. An urgent demand for 
fullers' earth suitable for use as a clarifying medium was received, and, 
largely through inquiries and investigations made by the Geological Survey 
and the Dominion Laboratory, it is believed that at least three satisfactory 
sources of fullers' earth have been discovered—one at Glen Massey, Wai¬ 
kato district; another at Croydon, near Gore ; and the third at Hokonui, 
Southland. Many samples of clay obtained by Mr. E. R. Green, Inspector 
of Mines, Dunedin ; by Mr. Boyd Bennie, Inspector of Mines, Huntly; by 
officers of the Geological Survey; and by others, were tested at the Dominion 
Laboratory. In addition to samples from the three localities mentioned 
above, the following clays were found to possess considerable clarifying- 
power :— 
(1.) Two clays from Whangarei district. 
(2.) A clay from Puketerahi, near Tairua. 
(3.) A pumiceous silt from the Gisborne district. 
(4.) Several samples from the Gore district, exact locality not specified, 
but probably near Croydon. 
Analyses of some of these clays are,— 
1. 
2. 
3. 
4. 
Silica (Si0 2 ) 
62-95 
61-65 
55-40 
56-80 
Alumina (A1 2 0 3 ) 
23-27 
22-57 
23-60 
30-00 
Iron oxide (Fe 2 0 3 ) .. 
1-44 
1-44 
6-70 
1-60 
Lime (CaO) 
0-70 
0-60 
1-20 
Nil. 
Magnesia (MgO) 
0-10 
0-10 
1-65 
0-23 
Titanium dioxide (Ti0 2 ) 
0-29 
0-29 
e • 
Alkalies (soda and potash) 
0-15 
0-25 
3-52 
0-55 
Moisture lost at 100° C. 
1-95 
3-64 
[- 7-93 
10-82 
Combined water and organic matter .. 
9-15 
9-46 
100-00 
100-00 
100-00 
100-00 
(1) and (2). From Glen Massey. No. 1 is moderately plastic, and No. 2 highly 
plastic. Tests have shown that, while both samples possess clarifying-power, No. 2 
is the better. No. 1 is suitable for use as a fireclay, and No. 2 for porcelain. Both 
are valuable clays, especially No. 2. 
(3.) From Mr. Terry’s property, Croydon, near Gore. The plasticity is poor, but 
the clarifying-power good. 
(4.) Fireclay from McSkimming’s pit, Mako Railway-siding, Hokonui Railway, 
Southland. This clay is highly plastic, and has good clarifying-power. As a fireclay 
it is of exceptionally good quality. 
OIL-SHALE AT WAIKAIA, SOUTHLAND. 
On the 10th and 11th January* last I visited Waikaia and, in company 
with several of the directors and shareholders, inspected the area held under 
* Written early in 1917. 
