118 MR. W. S. JEVONS : REMARKS 



A fresh feature is now to be noticed which, although 

 unconnected geologically with the gold, is of some import- 

 ance to our subject, because it often conceals the golden 

 strata and obstructs the miner in reaching them. 1 allude 

 to a great sheet of basalt or, in fact, lava, which at a very 

 recent geological period has overflowed the beds of auri- 

 ferous drift often to a thickness of fifty feet. At Ballaarat 

 this overflow has only partially taken place, and the viscid 

 current of lava appears to have been stayed in its progress 

 so as to form a plain bounded by a steep slope. A large 

 and irregular area of country in Victoria, perhaps one 

 hundred miles in length, is covered by this basaltic rock. 

 Melbourne stands upon the edge of the basalt, and its 

 houses and stores are built of this hard blue vesicular 

 rock. Standing upon the higher parts of that city, the 

 view extends inland over an immense sheet of lava often 

 nearly as level as the sea, and only covered by a thin layer 

 of fine brown soil. 



Extinct volcanoes also, unmistakeable in form and 

 nature, occur in several parts of this basaltic country. 

 Thus Mount Buninyong, lying seven miles east of Ballaa- 

 rat, is an obtuse cone of basalt, becoming more and more 

 scoriaceous towards the summit, whence I brought several 

 specimens of decided scoria taken from a slight depression 

 which was, undoubtedly, an imperfect crater. From this 

 mountain a very extensive view was obtained over a coun- 

 try generally flat. A mile or two to the north was seen 

 Mount Warrenheip, the counterpart of Buninyong, and, 

 like it, an ancient volcano ; while Mount Blackwood, Mount 

 Clarke, and other eminences lying at various distances 

 and points of the compass, could also be distinguished as 

 of similar origin by their isolated conical or rounded form. 



Again, twenty or thirty miles to the north of Ballaarat 

 there stand, scattered over the basaltic plain, a numerous 

 group of very smooth-rounded eminences known as the 



