The Heathcotian. 173 



Bellerophon cresswelli, Eth. 

 Tremanotus pritchardi, Cresswell. 

 Favosites grandipora, McCoy. 



IX, — Summary of Conclusions. 



1. The heathcotian series of Victoria consists mainly of 

 phyllites and schists, with diabases, porphyrites, and amphibolites. 

 Some of the igneous rocks are intrusive, others are eruptive, and 

 some are volcanic agglomerates. 



2. The heathcotian series is of pre-ordovician age. The 

 evidence at present is insufficient to show whether it be Cambrian 

 or pre-cambrian. It is probably, however, more recent than the 

 metamorphic rocks of north-eastern Victoria and of Dundas. 



3. The Dinesus ida beds may be regarded as of lower 

 ordovician age, and they contain a new genus of trilobite, 

 Notasaphus. 



4. Dinesus, so far as the available evidence goes, may be 

 included in the Asaphidae. 



5. The heathcotian series is best exposed on the Colbinabbin 

 and Mount William Ranges. The latter extends from Mount 

 William to the south of Lancetield Gap, and has an outlier in 

 Deep Creek, south-east of Lancefield. Representatives of this 

 series also occur at Dookie ; under the silurian rocks of Rush- 

 worth ; some miles west and north-west of Geelong, in the 

 valleys of the Barwon and the Moorabool ; at Mount Staveley in 

 Western Victoria. Probably also at Waratah Bay, Cape Liptrap. 

 Possibly also on the Howqua River. 



5. The heathcotian rocks formed, in lower ordovician times, 

 an extensive land area across Central Victoria. By the upper 

 ordovician times, the sea had spread eastward across what is now 

 the Melbourne basin and the Upper Yarra. 



6. The silurian system in Victoria may be divided into two 

 divisions, a lower or Melbournian and an upper or Yeringian. 

 The silurian system occurs partly in a series of gentle folds 

 and partly in belts along a series of meridional fracture 

 lines, along which the beds are intensely contorted. Going 

 eastward from the western edge of the series the main folds 

 in the silurian are (1) the contorted zone of the Melbournian 



