Geology of Warrandyte Goldjield. 549 



Allowing, however, for these possibilities, the structure of 

 the country surrounding Warrandyte does not support any 

 hope of a substantial extension of the present, or of the dis- 

 covery of a new goldfield. 



ihe second phase of the question is more difficult to deal 

 with. Extensive shallow workings exist along the line of the 

 Main South Anticline from the Great Southern Reef to the 

 Yarra, but their history is not fully known. The same may be 

 said of most of the other workings on the field. Throughout 

 the official records there is scarcely a hint as to the mode of 

 occurrence of gold, nor any light as to its origin and distribu- 

 tion. At the time of the writer's visit to Warrandyte, only one 

 mine — the Caledonia — was working, and from that no gold was 

 being obtained. Thus there is little to help the question. 



Most of the workings show that further effort was abandoned 

 when the level of ground-water was reached. The depth at 

 which the gold was obtained is recorded in the official returns 

 to 1898 fairly completely, and these show conclusively that the 

 great bulk of the gold was found at and above 150 feet below 

 the surface, and most of this within 100 feet from the surface. 



Most of the gold therefore up to 1898 was found within the 

 zone of oxidation or vadose zone. Since 1898 the Caledonia 

 and the Victory are practically the only mines that have been 

 working. The Victory went below the water-line, and some of 

 its gold may have come from there. At the Caledonia the level 

 of ground-water is near the surface, and the bulk of the gold 

 came from below that level — i.e., from the (probably enriched) 

 sulphide zone. 



It is important to determine for the point under discussion 

 whether the reefs are likely to prove permanent in depth and 

 whether secondary enrichment has taken place. As regards the 

 former, although the reefs are thin, there is ground for be- 

 lieving that they continue in depth. The minor folds are 

 clearly defined, and there is no reason to doubt that the frac- 

 tures which accompany them descend some distance. At 

 the 600 feet level of the Caledonia the reef became very thin, 

 but there was a roll to the east, which would probably account 

 for its pinching in. I was told that it became a strong reef 

 again below this level, when it had its normal underlie again. 



