Highlands of Western Vldorm. 269 



such a valley, full of aaigrilar Iilocks from the basalt, and with 

 its sides for some distance an almost continuous series of land- 

 slips. A similar explanation can be applied to Bacchus Marsh 

 itself. At the Minrsli the valley has been cut through the basalt 

 to the underlying terbiaries. Down stream deepening is less rapid 

 because the hard rocks extend to lower levels and are not yet 

 penetrated. Hence the valley has been greatly widened in the 

 soft rocks. When the Parwan has cut through the couple of 

 miles of basalt in its course betw^een its upper valley and the 

 Marsh, it will be able to deepen its upper valley again at a 

 more rapid rate and perhaps even to recapture what it has lost 

 to make the Eastern Moorabool. 



Professor Gregory has described the Grampians as ranges of 

 the Pennine type. The area of Upper Palaeozoic rocks forms 

 a great sjTicline with a few minor corrugations. The long gentle 

 slopes towards the syncline are near the direction of the bedding, 

 and the short steep slopes in their present form seem largely 

 due to strong jointing. A well-developed jointing also occurs 

 in a direction at right angles to the ranges contributing to the 

 jagged character of their summits. Selwyn shows a section of 

 the south end, and Krause^ has given a >ection near the north 

 end. The latter shows one of the minor folds. He also shows 

 the granitic rocks as intrusive, though in his description he re- 

 gards this point as doubtful. Two causes may have led to his 

 favouring the idea that the granodiorite was intrusive. In the 

 area afterwards worked for gold at Mt. William sandstone from 

 the high hills close by is common. In its natural condition it 

 would be difficult to see that this area was granodiorite covered 

 with a thin layer of debris from the hills, and he >eeuis to have 

 mapped it as sandstone with dykes. Also there are undoubted 

 dykes in the sandstone. Those with which I am acquainted at 

 Hall's Gap are more probably allied to the Coleraine trachyte 

 than to the granitic rocks. 



The strike of the Grampians sandstone varies considerably, 

 being distinctly west of north in the northern parts, but more 

 meridional or east of north in the vicinity of Mr. William. The 

 dips are usually low, but near Hall's Gap Krause records 77 deg., 



1 Profjress Report, Geol. Surv., Vic. I. 



