Art. XI 1. — On the Age of Auriferous Quartz Veins 

 and Alluvial Deposits in Victoria. 



By W. H. FERGUSON 



(Field Geologist, Department of Mines of Victox-ia). 

 [Read 13th July, 1899.] 



It has occurred to me that a short paper on the period of time 

 in geological history when the auriferous quartz reefs were 

 formed, which are now found in Upper and Lower Silurian rocks 

 in Victoria, as well as some reference to the age of the gravels 

 derived from them may be of interest. Of late years, by boring 

 and actual mining some of the southern leads have been traced 

 to sites near where the ancient rivers debouched into the ancient 

 seas, and their gravels are overlain with marine strata which 

 upon palseontological evidence may be classed as Miocene or 

 perhaps as Eocene. 



The finding recently of an auriferous quartz vein in the South 

 GlenJdne Mine proves, as many geologists and miners had 

 expected, that along the continuation of some of the belts of 

 auriferous strata reefs exist far out under the basalt of the plains. 



It is known that reefs in these positions exist, and that they 

 are covered by gra\e]s, so that it becomes an important question 

 to decide, whether at the time the earliest tertiary gravels were 

 formed, were there then auriferous quartz reefs in existence in 

 the Silurian strata. 



Many people are of the opinion that the deposit of gold in our 

 reefs took place in comparatively recent times, not earlier than 

 the Tertiary period. Murray^ states that Dr. Selwyn considered 

 that payable gold would not be found in Miocene gravels in 

 Victoria. Murray, however, says that Miocene gravels in Gipps- 

 land and in the Yarra basin are payably auriferous. 



There is, it may be mentioned, some confusion about the use 

 of the term Miocene, as some authors consider some of the strata 

 called Miocene by Selwyn's Survey are really Eocene. Murray 



1 Oeolog-j- and Physical Geographj- of Victoria, p. 152. 



