io6 
Mines and Mineral Statistics, 
The great denudation which the district lias sustained is at once 
apparent from the drift, together with its protective covering of 
basalt, having been cut up into these isolated patches or outliers. 
The remains of the drift can still be traced for some 17 miles 
up the river, and in parts it still retains a thickness of 70 feet. 
The patches which were worked, as enumerated in the above- 
mentioned paper, are as follows : — .Jordan’s Hill, 40 acres ; Two- 
mile Elat, 70 acres ; Eocky Bidgc, 40 acres ; Horseshoe Bend, 20 
acres ; Hassall’s Jtill, 340 acres. Total, 510 acres. 
A peculiar deposit of crystalline cinnabar was found in one 
patch. 
In the above localities the drift has invariably been met with in 
tunnelling under or sinking through the basalt, and in places 
where the basalt had been denuded away the drift has either 
disappeared or has been scattered over the neighbourhood. 
ISo diamonds have been found in tlie river bed, except in 
places where the diggers have discharged the drift into the river 
when washing for gold. 
The basalt when not resting on the drift frequently lies upon 
metamorphie shales, slates, sandstones, or greenstone. 
The general formation of the neighbourhood is regarded as 
Upper vSilurian, with overlying outliers of undoubtedly carbon- 
iferous age. 
The rocks in the vicinity are nearly vertical, with a general 
strike of ,W., and consist of red and yellow coarse and fine 
grained indurated sandstones ; thin white platy argillaceous shales ; 
pink and brown fine-grained sandstone, banded with purple stripes; 
slates and hard metamorphie schists ; hard brecciated conglome- 
rate, containing limestone nodules, fiint, and red felspar in a 
greenish silicioushase. And with these occur dykes and ejections 
of intrusive greenstone. 
The rocks aro generally devoid of mica. Eor the most part 
the Older Pieiocene diamond-bearing drift is coarse and loose, 
but parts are cemented together into a compact conglomerate by 
a white cement of a silicious nature, sometimes rendered green 
by admixture with silicate of iron ; in other cases oxides of iron 
and manganese have been the agglutinating agents. Diamonds 
were proved to exist in this solid portion by a special experiment 
of Mr. Taylor’s. 
The drift is chiefly made up of boulders and pebbles of quartz, 
jasper, agate, quartzite, flinty slate, shale, sandstone, with abun- 
dance of coarse sand, and more or less clay. 
The quartz pebbles are white, like vein quartz, but often 
encrusted with films of iron or manganese oxides. 
Many of the boulders and pebbles are remarkable for a most 
peculiar brilliant silicious polish, wWch is evidently not due to 
friction, since the cavities are equally well polished. Silicified 
