562 Clarke — On Australian Gold-Reefs. 



quartzites and shales have presented their edges to destructive 

 influences." 



In a subsequent number of the "Herald," the Eev. W. B. Clarke 

 states, that having read Mr. Hill's letter, and judging from the 

 extract given by Mr. Hill, as compared with Mr. Selwyn's 

 report, he is persuaded that Mr. Keene and Mr. Selwyn treat 

 of different matters. The former seems to refer to " quartz " 

 geologically below the Carboniferous formation. The latter re- 

 ports a " drift " of quartz merely, below the Miocene beds, 

 but in immediate association with them, and conformable there- 

 to. All this is quite different to what Mr. Hill supposes. He 

 adds, that geologists in Victoria are not satisfied with Mr. Selwyn's 

 generalisation, that because in some places the drifts have been found 

 non-auriferous, it is therefore to be concluded they are always so. 

 It is believed, that, if non-auriferous, they have been derived from 

 non-auriferous rocks, such as the Bacchus Marsh, and other Carbon- 

 iferous rocks, Mr. Selwyn considers them as derived from rocks of 

 " Miocene age." This has nothing to do with Mr. Hill's idea of 

 " Quartz " at the base of the Carboniferous rocks. 



In the Silurian rocks themselves there are instances of reefs without 

 gold for considerable distances. This was reported to the Govern- 

 ment in 1852. From a long experience since, in examining various 

 rocks, and in connection with careful analytical experiments, con- 

 dttcted by skilful analysts, Mr. Clarke states that all the evidence 

 about non-auriferous rock is merely negative, that gold does often 

 occur in rocks of all ages, and that he is quite satisfied that any 

 statement claiming discovery for indications such as Mr. Hill refers 

 to, is of no value. 



Mr. Clarke remarks further, that gold occurs in parts of the Carboni- 

 ferous formation, above and below the coal, and even in one instance, 

 in coal itself ; and that it occurs not only in the Siliu-ians, but in the 

 Calcareous conglomerates of the Secondary formations. He mentions 

 many of his own published observations, giving the following 

 extract from his report of the 28th December, 1852 : — "We may thus 

 be led to understand, why, as in Australia, ridges and bands of 

 quartz that follow the strike of the slates that contain them, may be 

 traced for miles and miles without a sign of auriferous mineral, or 

 gold, though in other instances, every quartz vein may be, more or 

 less, auriferous. The difference depends upon the ages of the silicious 

 intrusions, the impregnation of auriferous quartz having occurred at 

 various epochs." 



In conclusion, Mr. Clarke states that Mr. Selwyn's valuable obser- 

 vations on the Tertiary deposits of Victoria do not bear on any 

 practical question yet mooted in New South Wales. And although 

 at present he concedes to Mr. Selwyn's hypothesis about the Lower 

 Miocene drifts, the facts on which that gentleman bases his opinion, 

 have been, as he has shown, long known to himself, and " proclaimed 

 to the world." 



