208 PROCEEDINGS OP SECTION C. 



It is possible to divide the Palaeozoic formations into two great 

 groups, which are separated by marked stratigraphical discordance 

 from each other, and which may be shortly described as follows : — 



The oldest rocks which have so far been observed in the part 

 of Eastern Victoria, to which I now refer, form a great recurring 

 series of argillaceous and arenaceous beds with quartz veins, in 

 fact the goldfield series of the district. The few organic remains 

 which have been found in these sediments have been Graptolites 

 of Lower Silurian age.* These occur in several localities to the 

 east of the Snowy River. At the Limestone River, one of the 

 sources of the Murray, there are obscure " remains of corals in 

 metamorphosed limestones, which are probably Upper Silurian. f 

 The probabilities therefore are that the great series of older 

 Palaeozoic sediments in this district represent both the Lower and 

 Upper Silurian Periods, and as such I shall provisionally speak of 

 them. Stratigraphically the next succeeding formations are vast 

 extents of intrusive holocrystalline plutonic rocks, which have 

 invaded the Silurian sediments. I have carefully examined 

 numerous places in North Gippsland where contacts with these 

 rocks have been exposed, and nowhere have I discovered those 

 older formations upon which the Silurian strata must have been 

 laid down. In no case have I found that the Silurian beds have 

 been laid down upon the plutonic rocks, and my present impression 

 is that all the formations older than the former have been absorbed 

 by the invading magmas, which now in their consolidated condition 

 as quartz diorites, granites and granilites, abut in many places 

 against the truncated ends of the sediments. In some places 

 where the natural sections have been favourable, I have clearly 

 seen that the plutonic magmas have eaten their way upwards into 

 the Silurian beds. There is such a section in Tingaringa creek 

 in Eastern Gippsland, and I long ago figured another which I 

 observed at Beechworth.| 



Next in succession to the intrusive plutonic rocks is a great 

 extent, both horizontally and vertically, of acid volcanic ejecta, 

 constituting the formations which I have described elsewhere as 

 the Snowy River Porphyries. i; These occupy an area which may 

 be roughly defined as conforming generally to the space contained 

 between the Snowy and Buchan Rivers. These rocks consist of 

 ancient lavas, tuff's and agglomerates. In places within or near 

 their bounds arise through them mountains of porphyritic rock of 

 a granitic cliaracter, which I have seen reason to believe mark 

 the sites of volcanoes of that time. 1 1 



* M'Coy, Prodromus Palieoiitology of Victoria, Decade I. 

 t Murray op. cit p. 24. 



I Geological Survey of Victoria, Progress Report 11. p. 77. 

 § Op. cit.. Report III. p. 181. 



II Op. cit., Report III. p. 181. 



