212 Proceedings of the Royal Society of Victoria. 



Mr. Stirling (20, p. 29) may also be quoted in support of the 

 view that the Dandenong rocks, which he calls mica-diorites, are 

 much later than the underlying plutonic rocks. 



IX.— The Age of Mount Macedon. 



The stratigraphical evidence as to the age of the Macedon 

 volcano is very incomplete. It was post-Ordovician ; and it was 

 ■earlier than the adjacent basalts, which belong to some part of 

 the Upper Cainozoic. That is all that the available evidence 

 positively proves. 



The Geological Survey have regarded the mountain as Palaeo- 

 zoic. But as Mr. E. G. Hogg has remarked (5, p. 96), no 

 fragment of the Macedon rocks has been recognised in the glacial 

 conglomerates of Bacchus Marsh and Heathcote. This negative 

 evidence suggests that Macedon is later than the glacial series, 

 which at the earliest is Upper Palaeozoic. 



The thick Kerrie conglomerates which occur on the south 

 eastern flanks of Macedon are considered by Mr. Hart (9, p. 66) 

 to be probably earlier than the glacial series. No fragments of 

 the Macedon rocks have been found in these beds, so that the 

 dacites are probably later than the Kerrie conglomerates. 



The only Cainozoic rocks with which the Macedon series is in 

 contact are the basalts. 



Mr. Knox, M.H.R., tells me that it has been suggested that 

 some of the deep leads at Malmsbury originally flowed southward 

 over the present site of Mount Macedon. I know of no direct 

 evidence which renders this view either probable or impossible. 

 The suggestion, howevei', is of interest, as showing that its author 

 understood that Macedon is not a plutonic mass, and that it 

 is not of Palaeozoic age. If this hypothesis be correct then 

 Macedon is later than the beginning of the deep lead series of 

 Central Victoria, and is at the earliest, according to current 

 terminology, of " Miocene " age. 



At present we can only conclude that Macedon is certainly 

 post-Ordovician, most probably post-Palaeozoic, and certainly 

 earlier than the upper Cainozoic. It may belong to any. part of 

 the Mesozoic or Lower Cainozoic. If the dacite series be Lower 



