32 ANlSriVERSART ADDEESS. ' 



COPPEB. 



There are certain cases in wliicli tin becomes an indication of 

 copper. In Cornwall it is found tliat copper is seldom abundant 

 in a lode, unless gossan forms the back of tlie lode ; and oside of 

 tin very frequently occurs in the gossan. Formerly many copper 

 lodes hare been worked for tin. Mr. Carne, an author well 

 known among Cornishmen, states that gossan was worked for 

 tin as recently as 1827. Tin occui's as well as copper in bunches ; 

 and as much of the copper in New South Wales occurs in 

 bunches or "blows," it would be well if some experiments were 

 made to ascertain whether tin may not occur in our copper mines. 



Copper and tin appear to be as abundant metals here as in 

 Cornwall ; and if any reliance is to be placed on indications, 

 persons looking for the former in a granite country should search 

 at the junction of granite and the slates 4;hat often adjoin it. 

 Formerly granite was not considered a likely rock for copper ; 

 but it has been found that, in one of the richest copper lodes in 

 Cornwall, where the lode left the granite the copper ceased. 



A contrary fact relating to granite and gold is shown in Vic- 

 toria, as I have seen myself. The rich gold reefs of Castlemaine 

 and Bendigo stop at the junction of the slates and the granite. 



Another fact which I have observed is, that copper often occurs 

 in a wash of inconsiderable value, though deceiving to the eye, 

 on what is really a gold lode. Such is the case at Kilkivan, in 

 Queensland, and in other places. 



It is a pity we have no public record kept of the peculiarities 

 observable in the occurrence of our Colonial ores. It would be 

 very useful hereafter. 



I would invite particular attention to the condition of hardness 

 or of decomposition of our granites and traps ; inasmuch as 

 (especially of late) I have noticed the occurrence of elvans in 

 soft granite, and gold in decomposed trap, under circumstances 

 of great interest and importance. 



