44 Proceedings of the Royal Society of Victoria. 



Coole Barghurk Creek, there is a thick mass of volcanic rock 

 overlying the Ordovician. Its thickness we estimated at about 

 150 feet. The lower part of the igneous rock, as seen in several 

 sections, is very much decomposed, while that near the surface is 

 columnar and sound. It would appear from this that there is 

 some difference in the age of the upper and lower parts. 



On consideration we are inclined to think that the Newer 

 Volcanic rock here rests on the Older Volcanic without the 

 presence of any intervening beds, and it is not till we have gone 

 some three miles to the southward, in the neighbourhood of the 

 Maude Bridge, that we are able, owing to the occurrence of an 

 intercalated marine limestone, to separate the two with certainty. 



Under the volcanic rock occurs a deposit of sand and gravel, 

 which can be traced down stream till it is clearly seen to pass 

 in its upper part into the Lower Maude marine beds, the 

 representatives, as we have previously stated, of the Lower Spring 

 Creek series. To the northward these gravels, which are in 

 places represented by quartzites, have been shown by Selwyn and 

 the officers of his staft" to underlie auriferous gravels, and where 

 examined by them, to be not gold-bearing (5). From the data 

 thus obtained, as well as from observations on some of the older 

 gravels elsewhere, which were also non-auriferous, Selywn arrived 

 at the conclusion that gold was not to be found in Miocene 

 gravels. In the same report (5, p. 24) he says, "No beds what- 

 ever containing marine fauna are known in Victoria overlying 

 alluvial or drift gold deposits." Since then, howevei', such beds 

 have been found near Stawell under marine deposits of apparently 

 Eocene age. Selywn's explanation of what he held to be the 

 non-auriferous character of the Miocene gravels is that the age of 

 the auriferous quartz reefs was Post-Miocene, the non-auriferous 

 ones being of greater age. Now that we know of the existence 

 of detrital auriferous deposits of greater age, another explanation 

 of the absence of gold from the gravels north of Maude must 

 be sought, and the true one appears obvious. The gold in our 

 Ordovician is practically confined to beds of certain ages, and 

 we thus find the north and south lines of auriferous country 

 separated by barren belts. One of us has shown that such a 

 barren belt is indicated at Castlemaine by the presence of 

 graptolites belonging to what he has called the Loganograptus 



