168 Proceedings of the Royal Society of Victoria. 



western foot of the hills are the Lancefielcl beds ; going westward 

 we cross an ascending series of the ordovicians, coming first to 

 the Bendigo and then to the Castleniaine divisions of this system. 

 Whereas, on the generally accepted view that Victoria is in 

 the main one great synclinal, we should expect to find the 

 uppermost, and not the lowermost, of the ordovician beds 

 nearest to the junction with the silurians. 



So far there is no fully convincing, definite evidence of the 

 Silurian beds resting upon the ordovician beds. There are three 

 possible cases. Specimens collected by Mr. Ferguson in Wombat 

 Creek, in north-eastern Victoria, have enabled Mr. Robert 

 Etheridge, jun., to record the occurrence of silurian fossils from 

 beds above a series with ordovician fossils. But Mr. T. S. Hall's 

 determination of the graptolites from that area suggests doubt as 

 to the occurrence of both the ordovician and silurian systems of 

 that locality. 



A second possible case is at Costerfield. Ranft, in his " Origin 

 of Gold," refers to the occurrence of abundant ordovician grapto- 

 lites in the tip heaps in the mines of Costerfield, although the 

 beds on the surface are there mapped by the Geological Survey 

 as silurian. If Ranft and the Geological Survey are both right 

 in their determinations, then the silurians at Costerfield rest 

 upon the ordovicians. 



The third possible case is at Sandy Creek, a tributai-y of the 

 Mitchell River, in Dargo. Mr. Herman collected some fossils 

 there, which have been identified by Mr. R. Etheridge, jun., as 

 silurian, and the beds are marked accordingly on the last edition 

 of the Geological Map of Victoria. Mr. Herman, however, had 

 previously mapped these beds as middle devonians.^ The collec- 

 tion included a Frodudus. Mr. Etheridge suggests that this 

 fossil was accidentally included with the Sandy Creek fossils.- A 

 definite conclusion in this case must await further evidence. 



The Heathcote evidence gives a simple explanation of this 

 remarkable fact that there is no evidence of the super position of 

 the silurian on the ordovician. During the time of deposition of 

 the ordovician rocks a high ridge probably extended across 



1 H. Hennan : Trans. Austral. Instit. Min. Eng., vol. v., Paper No. 68. 



2 R. Etheridge, jun. : Note forthcoming in Records Geol. Surv. Vict. 



