The Heathcotian. 171 



Melbourne, in oui' most familiar silurian sections ; hence there 

 has naturally been a tendency to exaggerate the importance of 

 this folding in the Victorian series. The foldings occur on 

 certain lines of fracture and contortion, which are separated by 

 broad bands, in which the silurian rocks have a fairly normal 

 sequence. The silurian rocks seem to me to be bent into two main 

 Anticlinals and two main synclinals (PI. XXV., Fig 6). Along the 

 eastern side of Melbourne is an extremely contorted zone, which is 

 especially well shown in the cutting by the Yarra at the 

 Johnston Street Bridge and near Heidelberg. East of this 

 Melbourne fracture zone the beds have a regular dip to the west. 

 This slope is part of a great anticlinal, of which the axis passes 

 tlirough Warrandyte. Along this anticlinal axis there is another 

 line of contortions and faults, along which occurs a series of 

 a,uriferous quartz reefs. The eastern leg of the anticlinal is 

 much steeper than the western ; and beyond it we come to the 

 great synclinal which passes through Lillydale and Yering. We 

 will therefore call it the Lillydale synclinal. A smaller synclinal 

 with some Yeringian beds appears to occur in the upper Yarra. 

 Eastward again we come to another great anticlinal. Some 

 ordovician beds are exposed in the axis of this anticlinal near 

 Matlock ; we may therefore call it the Matlock anticlinal. To 

 the east again comes the great synclinal of Walhalla ; its two 

 legs are said by Mr. 0. A. L. Whitelaw to have a very regular 

 dip, though the beds along the axis line of this synclinal are 

 intensely folded and contorted. Beyond the Walhalla synclinal 

 the beds are unconformably covered by the rocks which are 

 included in the devonian system. 



In tracing the folding of the silurians it is important to get 

 a palaeontological basis for the correlation of the beds ; but 

 unfortunately, owing to the comparative scarcity of fossils, their 

 imperfect preservation, and the great difference in characters 

 between the limestone and shale faunas, the palaeontological 

 evidence is at present insufficient. There seems, however, to be 

 ■evidence of two main subdivisions ; the first we may call the 

 Melbourne series or Melbournian ; many fossils have been, 

 obtained from it at Moonee Ponds and at the Yarra improve- 

 ments ; and it can be traced north-westward from Melbourne 

 through Keilor, East Kilmore and Heathcote. The beds at 



