77 
branch of a larger lead running southward under the Black blag 
Lake, and more than TOO feet below its present bed. 
At Siberia, a deep lead is found at a depth of bo to 100 feet 
under what is now a hill. Some mining work done on this showed 
it to be a buried watercourse. 
At Kurnalpi, the celebrated alluvial workings were on the 
slopes of a hill on the edge of a lake, and the ground became 
rapidly deeper approaching the lake. 
At Nunngarra, on the Black Range, some work was done on 
two leads, one at least of which was traced to a depth of 40 feet. 
They disappear under flats through which they have not been fol- 
lowed. 
At Lake Darlot, a quite similar lead was lately followed from 
shallow beginnings on the hills near the St. George mine down into 
ground about TO feet deep, under the flats surrounding Lake 
Darlot. but has not been traced actually under the lake. Evidence 
that the ground deet)ens ratn'dly towards the lake is also seen in 
some of the workings in the Hats at the west side of the field. 
The above are all cases into which the writer has made per- 
sonal examination, and to him there seems no doubt possible that 
the leads are old watercourses in which there was a certain amount 
of concentration of alluvial gold by ordinary river sorting action, 
'I'he beds usually contain rounded and subrounded pebbles clearly 
due to attrition in running water. The most typical gravels are 
those in the Paddington and Oversight leads. 'I’here is generally 
much clay and satid with the gravel or immediately over it, and 
above the lowest part of the filling it is very usual to have thick 
beds of unctuous clay or “pug" of which the Kanowna “pug" is 
the mo.st marke<l and well-known occurrence. In the Oversight 
lead a layer of hard dolomitic cemented material lies in jdaces over 
the "wash" in the deep ground. Above the clayey and sandy layers 
nearly all the leads have a thick layer of oxide of iron, often show- 
ing concretionary and botryoidal structures, but not in my opinion 
])roperly to be regarded as true lalerite. There is a general scar- 
city of included superficial matter, and much of the iron oxide is so 
pure as to suggest that its origin was as a precipitated iron oxide 
rather than an efflorescent laterite- The normal succession of iron 
oxide upon fine sedimentary cays in these buried valleys suggests 
slow filling tinder lacustrine and subsequently marshy conditions, 
in which first fine silts and afterwards iron oxide precipitates were 
accumulated. I'he capping of leads by masses of somewhat spongi- 
form oxide of iron is so very characteristic in this Stale that the 
finding of a line of this sort of iron oxide, which is easily distn. 
guished from laterites and gossans, may almost be regarded as a 
probable indication of deep ground, with possible gold, beneath it. 
In all the leads which have been examined by the writer, the deep 
