206 Charle.s Fniner : 



been mainly preserved by faulting in the Werribee area, and in 

 all probability close examination would reveal like relations else- 

 where. 



Our Victorian peneplain, therefore, was for the m.ost part com- 

 posed of hard, folded slates, sandstones, and quartzites, with 

 accompanying gneisses and granites, the less abundant later and 

 softer rocks being preserved only in troughs and pockets. 



At some date to be decided, this extensive level surface was sub- 

 jected to great forces of uplift, which have ultimately at our 

 present day resulted in the old peneplain level in eastern Victoria 

 standing at 6000 feet above sea-level, in the Werrilx^e area at 2000 

 feet or less, gently sloping westward until at the Glenelg River, in 

 Western Victoria, it sinks below the younger beds of the " Murraj^ 

 Gulf." 



There are two means whereby we might attempt to arrive at a 

 decision as to the date of commencement of uplift : — 



(a) Physiographic evidence, amount of erosion during and sub- 



sequent to uplift, fault evidence, etc. 



(b) Palaeontological evidence — the selection of some bench 



mark with which we can correlate the beginning of up- 

 lift. 



(o) Physiogi'aiyhic evidence. — Both methods above referred to have- 

 been availed of. Much use has been made of physiographic evidence- 

 in New South Wales, but it does not appear to lead to very reliable- 

 results. There are enormous variations in the amount of erosion 

 accomplished during the same period at dift'erent points in this-. 

 States. 



(i.) At Dargo Higli Plains we have steep valleys 1500 feet in 

 depth cut since the beginning of the uplift, and Mr. Herman (ref. 

 29 and 30) refers on page 3.39 to " 3000 feet of vertical Cainozoic 

 erosion "in that area. 



(ii.) At Mount Buller (ref. 19, p. 396), tlie Howqua and Delatite- 

 have cut valleys nearly 4000 feet deep into similar hard slates and 

 granites during the same period. 



(iii.) In the Werribee area we have the Lerderderg, with its; 

 long and precipitous gorge, cut over 800 feet deep into very hard 

 folded slates. This is much less than that accomplished in eastern 

 Victoria, and shows how the factor of elevation affects the result. 



(iv.) Meanwhile, we have the Werribee, above Bacchus Marsh, 

 cutting a gorge about 700 feet deep in quite similar i-ocks subse- 

 quent to the Newer Basalt period, presumably a considerably 

 sdiorter time. 



