ON THE AUSTRALIAN GOLD FIELDS. 119 



Bald Hills, or Hills of Lava. They are of basaltic rock, 

 which, it is my impression, is not more vesicular or scori- 

 aceous than in other parts of the country; thus these hills 

 differ from volcanoes proper. It is no easy matter to con- 

 ceive the cause of these singular Bald Hills, or the source 

 of the immense body of lava which now forms the surface 

 of a large part of Victoria, and must once have been a 

 liquid mass, glowing in the open air. Among the various 

 ancient rocky strata of the globe, it is well known that 

 overflows and protrusions of volcanic rock are often met 

 with, while I am not aware that an ancient [i.e. primary, 

 secondary, or tertiary) volcano, embedded below more 

 recent strata, has ever been recognised. Is it possible 

 that in Victoria we find the type of the ancient volcanic 

 eruption in which lava was all abundant, while modern 

 volcanoes with lofty cones are distinguished by the dis- 

 charge of much gaseous matter ? 



But, to return from this digression : for many years — 

 indeed nearly up to the time of the geological survey of 

 Ballaarat — the gold miners had no thought that rich de- 

 posits of gold lay concealed beneath the basaltic overflow ; 

 but greater experience, combined with increased means of 

 penetrating the hard rock and of sinking deep and expen- 

 sive shafts, enabled them to trace out several fine leads of 

 gold, extending quite under the new town of Ballaarat up 

 to the lake or swamp indicated on the plan. Numerous 

 companies of co-operative miners have lately taken claims 

 on these leads and, with the aid of steam engines, pumps 

 and other machinery, are raising and washing great quan- 

 tities of gold. I descended one of these mines (on the 

 Malakoff" lead), being lowered by steam power down a 

 well-constructed shaft to a depth of three hundred feet. 

 From the bottom of the shaft a gallery had been driven to 

 reach the lead of gold^ which was then followed to the 

 limits of the claim. 



