Becker — Auriferous Conglomerate of the Transvaal. J 99 



intimate manner with the formation of the white quartz seams 

 which carry pyrrhotite and rarely pockets of gold. I made a 

 special effort to ascertain whether the dikes are in any way 

 connected with the tenor of the banket, and consulted many of 

 the most experienced managers on the subject, There is, I 

 believe, substantially no connection.* The ore at and near a 

 dike is sometimes rich and sometimes poor ; a single dike will 

 intersect one stope, or one reef, at a point where the assays are 

 high, and will cut another working or another stratum of pud- 

 dingstone in a poor patch. The conditions are such as they 

 would be if, after ore deposition were complete, the country 

 had been disrupted and injected with dikes having no connec- 

 tion with the deposition of gold in the banket. Mr. De Launay 

 came to precisely the same conclusion, and emphasizes it by an 

 " assay plan" with the dikes drawn into it, and this diagram 

 fully justifies his position. f Mr. John Hays Hammond, how- 

 ever, has very recently expressed his opinion that although it 

 is generally true that there is no ascertained connection be- 

 tween the richness of the banket and these dikes, there are 

 nevertheless notable examples of local enrichment due to the 

 proximity of dikes.;); Such exceptions seem to me hard to 

 prove, for I think it would not be difficult to find other cases 

 in which banket close to dikes is locally almost barren. Indeed 

 I have heard of such occurrences, but cannot believe the local 

 impoverishment due to the presence of the intrusive rock. 



In the foregoing pages an attempt has been made to gather 

 all the more striking facts which it is necessary to consider 

 in testing the theories propounded to account for the deposition 

 of gold on the Rand. One of them must be right. 



The theory that the banket reefs are of alluvial origin, rep- 

 resenting metamorphosed placers, was probably the earliest to 

 be suggested, and was held as long ago as 1887, when gold pro- 

 duction first began. Who first advocated this solution I am 

 unable to state. It has been supported in 1891 by Mr. De 

 Launay, who has since adopted another view, by Mr. Pelikan 

 in 1894, and by Prof. F. Zirkel. 



In 1888 Mr. W. H. Penning§ was led, mainly by the charac- 

 ter of the gold (which he describes as occurring in sharp grains, 

 not waterworn), to state: "I am convinced that it was de- 

 posited — at the same time the gravels were being accumulated — 

 from water holding gold in solution." This is the opinion ex- 



* Messrs. Hatch and Chalmers find no reliable evidence that dikes have acted 

 beneficially on the tenor of the reefs. The Gold Mines of the Rand, 1895, p. 72. 

 t Op. cit. p. 324. 



X Engineering Mag., Feb. 1898, p. 746. 

 \ Jour. Soc. Arts, London, vol. 36, 1888, p. 437. 



