president's address. 1227 



marsupials, ceratodus, araucarias, zamias and other ancient forms 

 of animal and vegetable life which are now found upon the 

 continent also attest the antiquity of the land ; and the different 

 Tertiary " deep leads " or buried river-beds, and the later deposits in 

 the principal valleys, are also evidence that the Dividing Range 

 has been subject to atmospheric influences varying in intensity 

 from a very remote period to the present time. There is, perhaps, 

 no portion of this epoch of greater importance than the Pleis- 

 tocene period. 



The Pleistocene deposits are indicated by such vast accumula- 

 tions of the drift and diluvial sediment which have been derived 

 from the erosion of the deep valleys in the highlands, and spi'ead 

 out over the low lying country, as to point to a time of much 

 greater rainfal than obtains at present. 



Were we from a great height to look down upon, or as it were 

 to take a bird's eye view of our country, or what would serve the 

 same purpose, to look upon an accurately made model of it, the 

 great Coast Range, the Barrier Ranges beyond the Darling, and all 

 the other surface prominences would resemble some railway or 

 other earth embankments, whose sides have been furrowed by the 

 action of rain, whilst the great plains of the Darling, and Riverina, 

 with their network of Billabong drainage channels intei-secting 

 them, would appear like the patches of silt filling the hollows near 

 the denuded earth embankment with the little water rills crossing 

 them. Our comparison would not be an inappropi-iate one ; for 

 many of the minor surface appearances are due to the same cause, 

 sub-aerial denudation, which in the one case has produced these 

 effects in a few years, whilst in the other the erosion is the work 

 of ages. 



But on closely examining the country we find that the present 

 surface features are but the production of the latest of many 

 changes that have taken place. 



As an instance I will give you a splendid section which is 

 exposed in the Mooi'abool Valley between Geelong and Ballaarat. 

 I measured the section myself some years ago. The river flows 

 over the upturned edges of an old slate formation, traversed by 



