12 F. L. mUlireU: 



Connected with this is the fact that the bulk of the gold ia in the 

 brecciated material, which would itself certainly provide the easiest 

 passage for soluticms. This is evidence which points to the conclu- 

 sion that the gold is secondary, meaning by this that the gold is sub- 

 sequent to the reef, that the gold haisi been deposited elsewhere first, 

 from there removed, and re-deposited in this breccia, and that therefore 

 there has been secondary enrichment in this particular spot. 



A drive was opened to the south from this winze for about a hundred 

 feet, and a second winze is being sunk. In this winze the lavas are six 

 feet apart, but the whole of the space between is not filled with quartz. 

 It is in part slate, and tlie reef, about three and a-half feet wide, pursues 

 a wavy course downwards. Occasional colours of gold, I was informed, 

 are seen throughout the reef, but the brecciated material seemed to be 

 absent. The reef in this winze is not nearly so rich as the No. I. winze, 

 and this erratic distribution supports the conclusion of secondary 

 enrichment. 



The lavas may infiuence the gold distrilnition in the following 

 ways : — 



(1) The heat accompanying the intrusions may stimulate the 



flow of tlie underground solutions involved in the formation 

 of the quartz reefs. 



(2) The lava sheets may act as an inpervious barrier to the transr 



verse passage of such solutions. 



(3) The lavas may form drainage channels for the vertical passage 



of such solutions. 



(4) The dyke n)aterial may act as a precipitating agent to the 



gold carried by traversing solutions. 



If the lavas are of the late geological date indicated by the i)etrolo- 

 gical evidence, the first of these methods has had no effect on the 

 primary deposition of the gold. Observations where the dykes cut 

 through reefs at the deeper levels, as at 2300 feet in the Catherine 

 Mine, Eaglehawk, and at 2600 feet in the Koch's Pioneer, Long (tuIIv, 

 are all negative, yielding no evidence of any influence on the gold 

 distribution. Such infiuence would be noticeable, if anywhere, in 

 the deepest levels, where the heat and stimulation would be greatest 

 and it is becoming generally recognised that the deeper reefs are not 

 so valuable as the shallower reefs. 



If the second method operated, one would expect enrichment only on 

 one side of a lava, cutting through a reef, and I have found no evidence 

 in this direction. 



The third method is one which I venture to suggest in explanation of 

 che above Ironbark occurrence. The evidence points to the circulation 

 of gold-bearing solutions subsequent to tin- iccf. and to the lava. The 

 evidence is not suificient to decide whether the solutions came from 



