150 Proceedings of the Royal Society of Victoria. 



Silurian rocks " ; so that we must interpret Selwyn's view as 

 being that the diabase series was intrusive in post-silurian 

 times. 



The next contribution to the Lower Palaeozoic geology of 

 Heathcote was a short but important note by Mr. E. J. Dunn, 

 published in 1889 ; he described the rock series as beginning 

 with some "schistose beds," (p. 77), followed by lower silurian 

 [ordovician] and upper silurian. That Dunn regarded the 

 schistose beds as older than the ordovician is stated by Sir F. 

 McCoy, when describing some markings from Heathcote which 

 he determined as worm tracks. Dunn's " Notes " moreover state 

 that the basic rocks, which he calls " greenstone " are intrusive.^ 



In 1894 Mr. Lidgey published a fuller account of the Heath- 

 cote rocks, in which he stated Mr. Dunn's views as to the 

 pre-silurian [i.e., ordovician] age of the metamorphic rocks. He 

 added the opinion that the basic rocks were lavas and amygda- 

 loid s. 



During the survey of this area by the Victorian Geological 

 Survey, Mr. W. H. Ferguson discovered a series of fossils, which 

 were described by Mr. R. Etheridge, jun., as of cambrian age. In 

 1896 Mr A. W. Howitt published the results of a most careful 

 microscopic study ot" the rock specimens collected near Heathcote 

 by the officers of the Greological Survey ; he recognised the 

 intrusive character of many of the rocks. According to his 

 instructions, Mr. Lidgey re-examined the ground, and some of 

 the sections were visited by Mr. Howitt. The result was the 

 conclusion that the rocks of the diabase series were intruded in 

 devonian times, and that they were injected along the line of 

 junction of the ordovician and silurian series. 



1 McCoy's note suggested that Dunn had done more work on the Heathcote rocks 

 than is given in his report of 1S89. On enquiry in tlie Mines Department, I have seen a 

 letter from Mr. Dunn (Cth July, 1891) in which he clearly expresses the view that the 

 Heathcote rocks include a pre-silurian system. He says— "'The formation is of pre- 

 silurian age, and the beds ot which it consists comprise highly siliceous and jaspideous 

 rocks, very talcose splintery schists, tufaceous deposits, quartzite, and ancient vesicular 

 basalts, once surface flows but now intercalated with other strata. The railway cuttings 

 near Heathcote expose a tongue of these rocks ; they extend and widen out in a northerly 

 direction towards Mounts Camel and Pleasant ; how far the.\- continue has yet to be deter- 

 mined, as I only discovered the formation on Saturday last, and traced it towards Mount 

 Camel." Mr. Dunn then makes the interesting suggestion that these rocks have marked 

 resemblences to the rocks of the Te Anari series in New Zealand.— J. W.G., 13-xi.-02. 



