1857.] SMYTH EXTINCT VOLCANOS OF VICTORIA. 235 



newer basalt, some of these volcanos were active, hut were not erup- 

 ting lava in such large streams as at former periods. 



4th. That the volcanic ash and scoriae resting on the ancient humus 

 found at Tower Hill, Mount Leura, and in the Korangamite district, 

 belong to a still later period, when the igneous force was almost 

 exhausted. 



The greatest extent of country throughout which the igneous force 

 has been exerted in this colony, and exerted for such a lengthened 

 period — the areas covered by the streams of lava, which are in some 

 places more than 25 miles in length, and of great thickness — the 

 occurrence of auriferous deposits around the great centres of action 

 — and the contiguity of the extinct cones to the great volcanic chain 

 extending from the Aleutian Islands to New Zealand, and probably 

 still further southwards, — all serve to render the question of the age 

 of our most recent volcanic products one of the most interesting 

 problems in geology ; and, as a step in this direction, the late dis- 

 covery at Tower Hill is obviously important. 



It has been said that the aboriginals point to Mount Franklyn 

 {Lame-bar amuX) as the spot from which smoke has been seen to 

 issue, and much stress has been laid upon this fact ; but, though 

 there is no doubt that Mount Franklyn is a recently-extinct volcano, 

 it is likely that the natives have framed such a story to satisfy the 

 demands of their interrogators. There is no evidence within my 

 knowledge which would show that any hills in Victoria have been 

 active volcanic points within the historical period. To say that the 

 ancient force is exhausted, or may not be again in operation, would 

 be untrue. Slight earthquakes have been occasionally felt ; and the 

 settlers speak of one having occurred some ten years ago at Mel- 

 bourne, which caused a considerable wave in the River Yarra. 



During a long- continued depression of the barometer in September 

 1855, the shock of an earthquake was felt over a considerable area, 

 sufficient to awaken sleeping persons, and to shake the walls of un- 

 stable buildings. 



We have proofs, too, throughout the whole line of our coast, that 

 many parts of it have been recently upraised. Large lagoons, now 

 bordering on the sea, are only a few feet above the tidal level, and 

 their beds are composed of clay and sand containing numerous shells 

 of existing marine species, — true post-pliocene deposits. 



This upheaval, like the preceding change of level, when the older 

 basalt and palaeozoic strata sank to receive on their surface marine 

 tertiary beds, to be again upraised and again depressed, has been 

 slow, and not violent. 



It would be very interesting, and useful in a practical point of 

 view, to ascertain whether this upheaval is still in progress ; and I 

 trust, when a proper system of tidal registration is initiated, that 

 steps will be taken to determine it with accuracy. 



VOL. XIV. PART I. 



