BY G. THUKEAU, F.G.S. 7 



"mud" is still retained within tlie "dead" vent or closed 

 fissure, and happily for the colony at large, it is comeatable, 

 and it can be extracted by future systematic mining operations, 

 followed by skilful treatment for the rich gold it is reported 

 same contains. 



With regard to the opinion I have had occasion to express 

 in my report to the Grovernment, I may add that the mining 

 operations carried on since still expose rich ores at times, and 

 as Mr. Johnston concludes his Paper by saying : It — the 

 hydrothermal theory — had also been adopted by Mr. Thureau 

 in respect to such mineral formations as the Iron Blow at the 

 Linda, although the latter " seems to be unaware of the fact 

 that the mode of origin of the more common quartz reefs are 

 also frequently ascribed to the hydrothermal agency." 



I may be permitted to state that, in the years 1845 to 1848, 

 when a student at the Royal School of Mines, Clausthal, 

 Hannover, Germany, I studied under several eminent pro- 

 fessors of geology, and at that time no less than five or more 

 theories — including what is now termed hydrothermal — were 

 tnown, recognised, and applied practically. Since then I 

 have been, and am still, an ardent student of mining geology 

 in several countries, so that it is not likely that I am ignorant 

 of so important a portion of that science. 



When I held, in 1875 to 1877 inclusive, the position as 

 Lecturer at the Bendigo (Victoria) School of Mines, of 

 " Geology as applied to Mining," Mineralogy ; also Practical 

 Mining, the Administrative Council of that institution 

 arranged during each winter for a series of public lectures on 

 Popular Science, and at such I elaborated a series of lectures 

 upon the hydrothermal origin of the famous Bendigo Quartz 

 Eeef s, without controversy. It appears that at those lectures, 

 — illustrated by models, diagrams, geological sj)ecimens, and 

 analysis, — visitors from England, 'New Zealand, and America 

 attended, and as one result of the interest they must have 

 taken in the subject dealt with, I was subsequently elected, 

 upon unsolicited nominations and recommendations, as a 

 Fellow of the Geological Society of London, which honoui'- 

 able position I still hold and treasure. 



