78 
leads appear to have been filled up and buried during a period long 
antecedent to the actions which have given the existing surface its 
present sha])c. 
Opposite the Kanowna railway station on the head of the 
“town lead.” we find a very hard silicious fine conglomerate lying 
over the wash layer in the lead. A somewhat similar hard cherty 
quartzite caps a small hill not far from the road to the racecourse, 
and under this caj) there is loose quartz gravel made up of pebbles 
of the thoroughly rounded marine type. Where this occurrence 
fits into the geological history of the locality is at present a matter 
of speculation so far as the writer is concerned; it is however, 
evidence of lacustrine or marine conditions in that area in no very 
(.listant geological period. The little gra\el hill is quite isolated, 
and is the only one of the sort seen by the w riter anywhere in the 
district, and it is certainly much older than the last stage of sur- 
face sculpture. It may be i)erhaps connected with the “cement” 
(fine grained conglomerate) beds of Kintore, but is evidently a 
relic of an older superficial formation which has otherwise almost 
entirely disappeared. 
'fhe Deep leads, however, are not by any means the only 
proof that there is often an older land surface buried under the 
existing i)lains, and which is often at such varial)le depths below 
the latter as to show that it was not so uniformly level as the pre- 
sent ])]ain surfaces. This is quite often seen in mining shafts and 
in stopes which come up close to surface, it being not at all uncom- 
mon to find much variation in the de])ths at which the bedrock is 
found beneath the surface. 'Fliis deep “surface” or “made ground” 
as the miners commonly call it, often gives considerable troul)le in 
tracing the outcrops of reefs into the flats, as it has to be sunk 
through to find the ontcrojis. l)e])ths of “surface” up to irld feet are 
not uncommon. Much greater dejiths of it are often found in 
sinking wells, many of which go dowm -”() to KK) or more feet before 
the bedrock is reached. Ibifortunately it is hard to get exact data 
on this matter, as the well-sinkers rarely make any distinction 
between soft weathered portions of the bedrock and the detrital 
de])osits which cover it. There arc a great many cases known 
where w'clls of (luite considerable depth are sunk almost from sur- 
face in soft weathered rock, which is merely the bedrock softened 
and kaolinised by weathering, and areas of such rock appear to he 
as useful in acting as reservoirs of under-surface water as deposits 
of superficial detritus. The records of ground passed through in 
well-sinking, therefore, are rarely at all de])endablc as showing 
whether the sinking is in detrital material or in weathered bedrock. 
A good deal of attention has been given by the writer when travel- 
ling about the fields to examining the dumps thrown out from the 
wells, and in making inquiries from men with knowledge of them 
to ascertain the depths at which the true bedrock has been encoun- 
tered, and there arc a large number of instances where the sinking 
