Highlands of Wesfrrn Victoria. 205 



iiiirive Mountain Cliain. Apparently this is regarded as Devonian 

 in ape. Mr. T. S. Halli has ascribed it to cross folding connected 

 with tho i)itL'h cdnnaonly observed in the folds of the older 

 rocks. 



I think it can be shown that any feature produced prior to 

 the deveh'pment of the peneplain must be of minor importance 

 in determining the position of the Main Divide. 



The gradient of the streams which formed the peneplain must 

 ha^-e been very i^light by the time that operation was finished. 

 Without takincr tho estimated grade as low as 1 in 50, 000, » we 

 may say that if as low a.s 3 feet to the mile (about the gradient 

 of a large part of the Tliames), it would be quite inadequate to 

 account for even the more modera.te inequalities of level of the 

 peneplain. Some other cause has established far greater differ- 

 ences of elevation than those of the peneplain as formed, and 

 this cause must have operated subsequent to the formation of 

 the peneplain. At Warrenheip the peneplain level is about 1750 

 feet above the sea level. Thirty miles to the south are contem- 

 poraneous marine beds which even allowing for depth of water 

 may be stated as elevated less than 700 feet. This gives a 

 difference in elevation equal to 1000 feet in 30 miles. From the 

 south-west of Daylesford to Warrenheip the general level of the 

 pen;^plain falls from aibout 2350 to 1750, or about 30 feet to the 

 mile. These would give slopes quite sufficient to overcome the 

 slopes of the original peneplain, though it would not neces- 

 sarily reverse the original slope in the vicinity of a I'idge. And 

 it must be remembered that the ridge remaining on the peneplain 

 would only be a very nmch modified remnant of an older 

 eminence. 



The more marked differences of elevation about the Grampians 

 and Pyrenees would be correspondingly more effective in over- 

 coming older inequiulities. 



Selwyns suggestion leaves the question very open if we 

 substitute peneplain for original sea bottom. Professor Gre- 

 gory's Primitive Chain, if it existed, would have been reduced 

 to insignificance in the formation of the peneplain, but there 

 are gi'eat difficulties in supposing its existence. In the first 



1 A'ietoriau Year Book, 190;^-C. 



2 Gregory, oj) cit., \i. 7S. 12 



