174 DISTRIBUTION OF BEDDED LEADS 



Aside from the necessity of sinking, the most important 

 feature which can be used, not for comparison but for contrast 

 with our local conditions, is the absence of any "horizon of 

 most abundant slate"; and the consequent diffusion of the veins 

 not only over a very great depth, but laterally over practically 

 the whole extent of the great dome, about 140 square miles. 

 We have exactly the opposite — much deeper legs to individual 

 leads, but a very limited lateral and vertical extension to the 

 domes or zones. 



It has been computed by one student of the series that the 

 difference in size between our folds and those of Bendigo is 

 approximately as 20 to 1 ; and this has been used to prophesy 

 the possible conditions underground as regards intervals between 

 leads not now exposed at the surface, and length of leg on 

 individual leads. Such statistics must be used with the greatest 

 care, if at all : and in this case they are better discarded 

 altogether. For if we push figures like these to their ultimate 

 end, they act as boomerangs and discourage us completely. The 

 fact is, the tw^o districts are dissimilar in many essentials, while 

 the superficial similarity of both containing bedded veins has 

 blinded students to the relative value of the totally different 

 factors entering into the equation of the tw^o deposits. There 

 are other regions of bedded veins in the world besides these, and 

 altogether too much importance has been attached to the really 

 accidental method of occurrence. To return to Bendigo, if our 

 deposits are on a scale of 20, we miy expect to go 50,000 feet 

 vertically in some places to strike live leads, to use Lansell's 

 " 180 " mine for comparison. Again, the 4,000 feet now reached 

 by several mines represent 80,000 feet in which we may expect 

 to find productive veins — which is too ridiculous for comment. 

 No ! The fact that there happens to be about that difference in 

 the scale of construction of the folds in the two countries is 

 interesting, but utterly worthless for prophetic purposes. 



We have seen that our own veins are, to some considerable 

 extent, localized within small domed districts ; that these dis- 



