The Heathcotian. 167 



The confused rocks at Waratah Bay, Cape Liptrap, may 

 include an outcrop of the Heathcotian series. Mr. Stirling^ has 

 recorded the occurrence there of "hard felsitic beds "" either 

 Silurian or pre-silurian " ; of a gabbro with serpentine veins; and 

 of a " hornfels-like contact rock." But he regards the gabbro 

 and diabasic rocks as associated with deep-seated apophyses, fron» 

 the granitic area of Wilson's Promontory ; and the granitic 

 rocks there have been generally regarded as devonian in age. 



On Mr. Stirling's plates some rocks in fig. 1 are marked as 

 Cambrian ; in fig. 2 the diabase or " melaphyre " is shown as 

 intrusive into the silurian (?) ; in the view of Waratah Bay the 

 "felsitic jointed rock" is stated as pre-silurian (?) ; and in the 

 sketch section at " Serpentine Dyke, to west of Bird Rock," it 

 is said to be cambrian, and the serpentine is shown intrusive into 

 it, separated by a "contact rock (mica porphyrite)."'- 



Another area where Heathcotian rocks may occur is on the 

 line of junction of the silurian and devonian rocks in Wonnan- 

 gatta. The most probable locality would be in the Howqua 

 Valley, south of Mount Buller. Mr. Murray's" report on this 

 district refers to the upper silurian beds being there "partly 

 metamorphic in character." So far T know of no certain evidence 

 of Heathcotian rocks in that area. 



VII. — Relations of the Ordovician and Silurian Systems. 



The above conclusions help us to understand the relations of 

 the ordovician and silurian deposits in Victoria. It has been 

 well known since the time of Selwyn's work that the ordovician 

 and silurian rocks meet along a line running from Melbourne 

 northward through Heathcote; but no very satisfactory junctions 

 have been found along this line. 



Starting at the Mount William Range the hills are formed by 

 a continuation of the Heathcotian series. Immediately at the 



1 J. Stirling : Notes on the Silver Deposits and Limestone Beds of Waratah Bay. Projf. 

 Rep. Geol. Surv. Vict., No. viii., pp. 68-69, pi. 4. 



■■: The general impression left by the above account is that the rocks are probably 

 Heathcotian ; but one of my colleagues on the Geological Survey is of opinion that the 

 supposed pre-ordovician roclis are altered Silurians. 



3 R. A. F. Murray : Howqua Hills District. Prog. Rep. Geol. Surv. Vict., No. vii., 

 1884 (1885), p. 57. 



