ON THE AUSTRALIAN GOLD FIELDS. 127 



plastic quartz is forced out, of course the hornblende and 

 feldspar are left behind to form the walls of the reef. 

 Among Silurian rocks we never, I believe, find hornblende 

 near the quartz, and only in the instance of the feldspathic 

 porphyry at Maryborough, do we find any plutonic rock at 

 all present. 



The gold districts of Victoria, including the southern 

 parts of New South Wales, I regard as a great mass of 

 auriferous granite, upon which lie Silurian strata of a 

 slight thickness. Granite protrudes bodily from the sur- 

 face in very many places, of which the May-day Hills, 

 Mount Alexander, Mount Tarrengower, Adelong and 

 Braidwood are only a few of the best known. In other 

 parts the liquid quartzose constituent of granite has alone 

 been forced upwards, filling a system of fissures which 

 have an almost invariable direction from north to south. 

 I am in no way called on to explain the cause of these 

 parallel fissures, for the same parallelism is well known to 

 be a characteristic of all systems of mineral veins, or 

 fissures filled by mineral ores, in Cornwall and elsewhere. 



Some of the opinions above expressed were entertained 

 many years ago by the Rev, W. B. Clarke, of Sydney, a 

 geologist who had discovered gold in New South Wales 

 many years previously to Mr. Hargreaves's practical dis- 

 covery, and who is better acquainted with the geology of 

 Australia than any other person. 



///. On the future Supply of Gold. 



The question, Will the supply of gold from Australia 

 increase, remain constant, or diminish ? is of evident and 

 high importance. I will therefore conclude with a few 

 remarks by way of answer. 



The rich diggings of Ballaarat, Bendigo and Forest 

 Creek were all discovered in the course of one or two 

 years after attention was first drawn by Mr. Hargreaves 



