736 PROCEEDINGS OF SECTION F, 
position of Post-Tertiary deposits in Victoria, Tasmania, and the 
islands of the Strait, may not exceed 50 to 60 feet.* 
There are some grounds for the belief that the upward move- 
ment is still continuing. 
In this brief summary the main features in geological history, 
and in the physical geography of Victoria and South Australia, 
which seem to have a bearing upon the questions discussed in this” 
address, are the following :— 
‘An elevation of the land following an Eocene or Miocene sub- 
sidence, which in the Pleiocene was accompanied by or culminated 
in the newer volcanic when the newer deep leads of Central 
Victoria were formed. Finally a resubmergence of the land in 
late Pleiocene or Post-Pleiocene times, by which Bass’ Straits were 
formed. 
I have been long impressed by the fact that the “deep leads” 
referred to—that is, the ancient. river channels—are now at con- 
siderable depths below the surface over which the modern rivers 
flow, with but a slight fall to the sea by way of the Murray River 
valley. 
During the past thirty years the Victorian Department of 
Mines has carried out an immense amount of boring with the 
diamond drill, by which the underground contours of the valleys, 
and also the trend of the deep leads, extending north and south 
from Ballarat, have been ascertained. 
Tt seemed to me that a comparison of the data thus obtained, 
with the surface features, might prove of interest, and for this 
purpose I have selected the statistics of bores put down furthest 
north on three main leads, where the hilly country subsides into 
the great levels of the plains through which the river Murray 
winds its course towards South Australia and the sea. 
Each locality chosen was also not far distant from the termina- 
tion of the flow of basalt, by which the old valley had been levelled, 
and which itself was, at its termination, levelled of by the later 
alluviums of the plains. 
The following are the data from which I was able to draw 
certain conclusion :— 
No. 9 Bore at Bung Bong. 
Height of surface above sea-level ; ane ... T14 feet. 
Depth of deep lead channel below the surface} iy OOCwas 
Distance from the bore to Swan Hill, on the river 
Murray, by way of Bet Bet Creek and the Lodden 
River oh 3 Pe ue fe . 200 miles. 
* XXXII, p. 320 et inpa. 
+ In each case, in order to approximate the conditions of the “lead” with those of the 
river Murray, ‘I have deducted from the results of boring the depth of ‘‘ wash,” and have 
also allowed 5 feet for the possible depth of water. 
