:242 Charles Fenner : 



Bay Were slightly exaggerated in the figure in order to sIioav that 

 feature. The eastern boundary, Selwyn's fault, has been proved 

 to be of greater age than the western boundary, the Rowsley scarp. 

 Probably later movements have taken place on the east (ref. 8), 

 .and earlier ones on the west, although the latter have so far not 

 l>een demonstrated. 



(b) l^he Ballan Sunkland. — This area has also been previously 

 •described, as regards it-s economic and. other aspects, having been 

 referred to as block B. It is bounded on the north by the Greendale 

 fault, and by a fault of probably similar age on the south, shown 

 in Fig. 5. On the west the suggested boundary is the Doran- 

 Egerton line, beyond which no glacial nor older ba&aJt is preserved 

 as far as known. In the east, the Ballan sunkland is bounded by 

 the Rowsley fault, and stands higher than the Werribee plains; it 

 may be known alternatively as the Ballan Plateau, a distinct 

 geological unit in the larger Ballarat Plateau (refs. 20, 21). A 



Bvkr<; f ". BLACKWOOD RANGES 

 /FAULT \ jN. 



HORIZONTAL SC4LE: ° \ 1 L_i J '^"-^S- Ordovician. Gwihc PtrrJiMarB Older TcrHary. Newer 



Volunic Volcanic 



Fig. 13. — Section across the Ballan Sunkland, showing geology and 

 relief. Note the complex structure of the let-down block. In 

 these sections the geology is necessarily to some extent diagram- 

 matic. 



section drawn to scale from, the Military Survey maps (50 foot con- 

 tours), with the geological formations diagrammatically suggested 

 is shown in Fig. 13. 



(vii.) Final conclusions as to age. — We see then that there are 

 here two dominant and undoubted faults with fairly clear age 

 relationships, and these should prove important factors in arriving 

 at the precise period of uplift of our highlands, a matter which we 

 have already discussed. The writer is led to the conclusion that — 



(1) the peneplanation was completed about the time of the Older 

 Volcanic period. 



(2) Differential uplift took place subsequently with extensive 

 faulting. 



(3) Dissection, etc., continued up to the Newer Volcanic period, 

 closely subsequent to w^hich a further series of uplifts occurred, 

 slowly bringing the main highlands of Victoria to their present 

 general levels. 



