Mines and Mineral Statistics, 
79 
aLoiit 100 foot iliroTigli the basalt, l)Ottonibig on gi’anite, without any 
intervening drift ; but. as the bed rock was dipping fast to the north 
the deeper groiind will be found in tliat direction, and whieli the con- 
formation of the contiguous granite ranges would also suggest. 
In niy former report J mentioned an old lead which crosses the New 
Banca Tin-mining Company’s ground. I have since traced this lead 
for more than a mile to the soiitiv-west ; its course being marked in 
places by a liard, white, siliciotis conglomerate. I believe tliat it 
crosses Cope’s Creek, between Captain 8\vintou’s station and Tiengha, 
and tliat tlie tract of country occupied by tertiary red sandy clay, 
south of Copehs Creek and passing near Stanborough, indicates the 
course it has taken. I cannot, however, spealc with certainty on this 
point, not having had sullicient time to examine the ground minutely. 
Outlying patches of drift, partly covered by l>asaltic trap, occur on 
the hills south of Cope’s Creek, near Sutherland’s 'Water, and also on 
the Eismart'k Tin Mine. 
Between Inverell and Middleton the tertiary rocks forming the red 
hills cover up the granite formation to a considerable extiuit. I am 
not aware of its having been pi'ospected. There may, howevei’, exist 
as pa^^able drift in this as in those localities above di'seribech 
On the Borah Greek, whicli hows into the Gwydir, about 2 miles 
above tlic junction of the river with Cope’s Creek, several patches of 
pebble-drift, iron-stone, and clays, capped with basalt, mark the course 
of a small lead. Not far from its source the Borah Crei'k crosses the 
lead, and for about 21 miles further down the valley, whieli lies 
between abrupt granite ranges, it Las been entirely denuded ; but 
below this point it may be traced now and again, in a N.E. direction, 
by pateJies of drift covered with basalt. ft is immediately bi'low 
where the creek lias first cut through the lead that the operations of 
tlic Borah 'bin and Diamond Mining Company liave been carried on 
in sluicing the more recent alluvial drift. Beside several tons of 
stream tin, upwards of 200 diamonds were obtained in a few months. 
Mr. Thos. Adams, one of tlie proprietors, siiowed eighty-six of the 
dianionds, which I weighed and found to average one carat grain each 
— the largest of tlicm weigliing 5*5 carat grains. They were mostly of 
a light-etravv and pale-greenish colour. Several were nearly octahedral 
crystals, but tlic rest were modifications, with curved facets and edges, 
some appealing almost sphencal in shape. Sapphires and garnets 
occur in the diamond-bearing drift, together witli small polished black 
pebbles. If tlie diamonds have been derived from the old leail, no 
doubt many more u ill bo found where it lias been entirely denuded, 
and the tin ore and diamonds it contained liave been redistributed in 
the alluvial deposits lower down the creek. Prom the Bengonover 
Mine (Messrs. Butler, Swansons, & Co.), about 2 miles below the 
Borah Mine, J examined several diamonds ; tlic largest, not ot good 
form, weighed 7*5 carat grains, and gave specific gravity 3'4. 
At the time of my visit the diamonds were reported from the Buby 
Tin Mine on the Borah Creek, about a mile above its junction with the 
Gwydir Eiver. 
The fact that the diamonds from the Borah Mine are found in the 
creek, immediately below where it has cut through the lead, suggests 
the impression that they have been derived from the lead. The small 
black pebbles associated with the diamonds may point to tlio former 
existence of another formation, hut no vestige of it in situ, that I am 
