Mines and Mineral Statistics, 
12 ; 
in many parts of the continent, numerous volcanoes burst out, 
their intermittent streams of lava pouring into the adjacent 
valleys, overflowing river courses and the bordering forests, and 
ill their onward progress spreading far and Avide, to form those 
rich basaltic downs of the western districts. These features are 
frequent both in Ncav 8011 th A\^ales and in Victoria, and it is of 
great importance that they should be carefully investigated, not 
only with the object of elucidating geological history, but also a 
correct understanding of the tacts they reveal Avill greatly facili- 
tate the progress of mining the deeper alluvial leads. Those 
buried old river beds noAV constitute the so called deep leads. As 
vet they have been tested only near tlieir sources, Avhere they 
formed but the tributaines of some larger river-channels not yet 
discovered, but the existence of which is obviously certain. Mr, 
T. A. Brown, AVarden at Giulgong Grold Fields, bas expressed his 
fixed belief in tlie future discovery in his district of rich deposits 
underlying the basaltic formation at greater depth than has 
hitherto been reached. And Mr. Fred. Dalton, A\ arden, in his 
annual I’eport for 1874, gives the folloAviug interesting particulars 
respecting the deep leads in the Lachlan Mining District : “ On 
several leads discovered and worked during the past year it has 
been, proved that the deepest ground is not auriferous ; shafts 
have been sunk to depths A'arying from 140 to IGO feet, and 
bottomed upon a Avash-dirt that differed in no respect from that 
obtained in adjoining claims at depths of from 80 to DO leet, 
except that the former did not contain any gold, while the latter 
yielded from 10 to 15 dwts. per load. These Avatercourses run in a 
parallel direction, and are not 100 yards distant from each other. 
Such not uncommon occurrences may have originated in various 
ways. For instance, at the particular time ot the deposition of 
the gold-hearing drift, the old stream may have been Avearing 
aAvay and distributing as drift some auriferous bed of rock or 
quartz reef Avhich had no great depth ; consequently, Avhen the 
river had eroded its channel to a lower IcA'^el, the underlying rock 
it then acted upon may have been non-auriferous, and therefore 
the drift derived therefrom Avould be so also. Again, in siluriau 
country there have been frequently noticed belts ot non-produc- 
tive rock, running parallel and alternating with rich tracts ; 
these then under certain circumstances Avould also afford an 
explanation of the above-mentioned facts. I could also 
instances Avhere alluvial drifts had derived their richness from 
the bed of an old auriferous lead wFich had been cut through,^ 
and its contents redistributed ; any further deeiAcning theretore ot 
the valley in the rock bcloA\^ the old lead, Avould cease to produce 
payable drift ; in this manner also may it often occur that the 
drifts left at various heights in the same valley will difter lu 
richness. 
