Mines and Mineral Statistics. 
109 
^ In tlie former sinkings made Idv tie gold diggers diamonds 
have occasionally been met witli at depths of GO feet, or even more ; 
but, as the men were working for gold, no great attention was 
paid to the diamonds, and it is quite likely that they fell in from 
tlie surface. 
The method employed iu tlie search for the precious atones is 
very simple The drift is stripped off and carted to the puddling, 
machines, Avherc it undergoes a great diminution in bulk by the 
removal of the clay and hne sand; the large pebbles are then 
screened oil. and the clean gravel remaining is passed through 
one of Hunt’s diamond-saving maeliines. But since this ap])aratiis 
depends upon the principle of separation by difference in specific 
gravity, it docs not perhaps afford the best method which could be 
devised ; it may answer well enough for gold and other bodies of 
very higli specilic gravity, but must certainly answer very imper- 
fectly for diamonds, on account of their comparatively low specific 
gravity, viz., ;T4 to 3*5, -whieli is nearly equalled by most of the 
accompanying minerals, and exceeded by some. 
I should 1)0 inclined to recommend the methods employed in 
Africa and Brazil, since they would probably prove more 
efficacious. 
We may now pass on to consider in more detail the mineral- 
ogical nature of tlie drift, or "‘wash-dirt” as it is termed by the 
miners. 
Brom Messrs. Westcott and M‘ Caw’s claims I obtained three 
different specimens. See samples Hos. 1, 2, and 3. 
IVasli-cliri JSo. 1. 
This is a pale brown clay, binding together well-rolled pebbles, 
suhangular and angular fragments of variously coloured jasper, 
red, green, bi’own, &c. Also black flinty slate, tourmaline, argil- 
laceous sandstone, and shale, &e. 
WasJi-dirf JSR). 2. 
This is rather darker in colour than Ho. 1, and the clay is more 
tenacious, the coutaiaed pebbles arc of much the same character ; 
the clay has a hrecciated structure, and difiers in colour in parts, 
fragments of it being nearly white. On the spot, when freshly 
dug out, portions of the clay are of a bright green colour, clue to 
the presence of a ferrous silicate, which, by exposure to the air, 
absorbs oxygen, and passes into the reddish ferric silicate which 
imparts the red colour to the clay. 
Wash-dirt No. 3. 
This kind contains a larger proportion of pebbles than either 
Ho. 1 or Ho. 2 ; it is of a light colour, and much less indurated, 
being of a sandy nature. This also contains pebbles of argillaceous 
shale. 
