RECENT ADVANCES IN SCIENCE 381 



Influencing Gold Deposition in the Bendigo Gold-field," Part II 

 {Commonwealth of Australia, Advisory Council of Science and 

 Industry, Bull. No. 8, 191 8, pp. 45). The chief new point is 

 that the force of crystallisation of the quartz is regarded as 

 instrumental in opening up the fissures (see Taber's views 

 below), although some reefs have been formed by the infilling 

 of already open fissures by quartz, and others are due to the 

 replacement of slate and sandstone. 



In a discussion of Stillwell's earlier paper (see Science 

 Progress, 191 8, 13, 215) S. Taber advances the view that 

 the veins have largely made room for themselves by mechani- 

 cally displacing the country rock. He does not think it pos- 

 sible that large cavities could remain open at the crests of the 

 folds during a period of intense folding under conditions of 

 deep burial and great pressure. Possibly small cavities were 

 filled by the silica-bearing solutions, and some replacement of 

 country rock effected ; but both these processes are believed 

 to have been of minor importance {Economic Geology, 191 8, 13, 

 538-46). 



Stillwell replies to this criticism {Ibid., 1919, 14, 430-4) 

 by pointing out that he has partially adopted Taber's views in 

 his second paper. 



The first full description of the famous Charters Towers 

 gold-field of Queensland is given by J. H. Reid {Geol. Surv. 

 Queensland, Publ., No. 256, 191 7, pp. 236). The country rock 

 consists of a pre-Devonian metamorphic series of schists, slates, 

 phyllites, quartzites, etc., which are intruded by a great mass 

 of granodiorite. This, in its turn, is intersected by numerous 

 sets of dykes. The lodes occur along fault-fissures in crushed 

 granodiorite and consist of quartz reefs carrying pyrite, galena, 

 zinc-blende, and native gold. Of rarer occurrence are tellurides 

 of gold and silver, arsenopyrite, and chalcopyrite. The two 

 main auriferous belts are connected with groups of diorite- 

 porphyrite d}^kes. The ores are believed to have been 

 deposited by ascending magmatic waters at intermediate 

 depths. 



The Amisk-Athapapuskow Lake District (Saskatchewan- 

 Manitoba), described by E. L. Bruce {Geol. Surv. Canada, 

 Memoir, 105, 191 8, pp. 91), consists of an immense series of 

 Archaean granites, schists, and gneisses, partly covered by 

 Ordovician limestones. Some rich gold quartz veins occur 

 in the older Archaean rocks, along with chalcopyrite-sphalerite 

 replacements which carry low gold and silver values. Both 

 types are believed to be genetically connected with the granite 

 batholiths. 



The controversy as to the origin of the Sudbury nickel ores 

 is carried further by Roberts and Longyear in a paper on the 



