Notes on the Area of Intrusive Rocks at Dargo. 149- 



has hitherto been given to it, for in general nothing was 

 done with the taihngs except to facilitate their departure 

 from the mill, and no care was taken to learn whether any 

 gold was being carried away in them or not. 



In some instances in past years I have obtained samples 

 of pyrites from such mines in the district, which in all cases 

 proved to be auriferous, up to over in one case 70 oz. to 

 the ton of pyrites. 



The want of success in the working of the contact reefs by 

 incorporated companies in the past is brought well into view 

 by comparison with the individual efforts of Mr. Peter 

 Forsyth, an enterprising quartz miner, at Swift's Creek, who 

 for some years past has perseveringly worked on his own 

 account with satisfactory results on one or other of the 

 contact reefs of that district. At the Budgee Budgee Beef 

 the Messrs. Hardy and other miners are now working with 

 prospects of ultimate success. 



It seems probable to me that the auriferous contact reefs of 

 Dargo, Swift's Creek, and Omeo will in the future be worked 

 somewhat in the manner now indicated, and with remunera- 

 tion to those engaged upon them. This would be a true 

 revival of one branch of quartz-mining. It would not afford 

 a field of operation for the promoter of companies, but it 

 would give remunerative employment to men who wished 

 to work on their own account, and who would be content 

 with doing so in an unpretending manner, for moderate 

 returns on the capital invested. 



There is one question which I have not yet considered, 

 namely, the probable origin of such reefs as those of Dargo. 



Such quartz veins are found either in the intrusive 

 plutonic rocks where laid bare by denudation, in the contact 

 between them and Silurian sediments, or in the latter, where 

 either metamorphosed into liornfels, or at a greater distance 

 from the contact in a more normal condition. It is safe to 

 assume that the quartz veins in the plutonic rocks once 

 extended upwards into the sediments whose denudation 

 has supplied the streams with the alluvial gold, and that 

 those now found in the contact zone would, if traced to 

 sufficient depths, pass into the intrusive rocks. Such 

 veins fill fissures whose original width may have 

 depended upon downthrow or upon a side shift which 

 brought discordant parts of the walls together, and 

 thus prevented the complete closing of the fissure. Narrow 

 and regular veins, such as those at the Exhibition mine. 



