Age of Auriferous Quartz Veins. 117 



In speaking of the Bendigo rocks Mr. E. J. Dunn^ says : 

 "There is no evidence that the quartz formed veins in the 

 Silurian rocks before they were bent and folded, but from that 

 time down to the present there is proof that tlie process has 

 been continually in progress, and quartz veins have formed 

 since the latest known dyke matter was injected." These dykes 

 are supposed to be of tertiaiy age. The main lines of " saddle- 

 reefs " Mr. Dunn considers to be of vastly greater age. 



Mr. E. Lidgey- refers the quartz veins of Ballarat to different 

 ages, the cross-courses of the " indicator-belt " being younger 

 than certain main lines which exist on the field, and he states 

 that their formation was probably started when the Lower 

 Silurian rocks of Ballarat were uplifted above the ocean and 

 folded and crumpled. 



Mr. H. Herman"* shows that an auriferous seam occurs in the 

 Upper Devonian rocks of Gladstone Greek, Gippsland, but he 

 does not state at what period the gold was deposited in this 

 seam. From an inspection of his sections, it must have been 

 contemporary with or sub.sequently to the formation of the 

 Upper Devonian .strata. 



In Victoria we have cemented and uncemented gravels of 

 many ages from Recent through Tertiary and Mesozoic times to 

 the Upper Silurian period, some of these are auriferous, but 

 geologists differ as to the age of the most ancient gravel which 

 is likely to contain gold, either in payable or unpayable 

 quantity, such gold being of a water-worn character. Murray, 

 in his "Geology of Victoria," writes that much of the stony 

 material and gold of our payable gold drifts was probably 

 disintegrated from matrices and rock masses during Palseozoic 

 and Mesozoic times, and that it is not improbable that some 

 of the lowest beds of the Mesozoic strata between Foster and 

 Turton's Creek may consist of auriferous conglomerates. With 

 this locality I am not familiar. In most places in Victoria 

 where I have noted the beds underlying Mesozoic strata, they 

 are conglomerates formed by glacial or drift-ice action, and the 

 fragments of which they are composed are foreign to the local 



1 Report on the Bendigo Gold Field, Dept. of Mines Special Reports, p. 26. 



2 Report on the Ballarat East Gold Field. 



3 Trans. Australasian Inst, of Mining Engineers, vol. v., 1898. 



