Coast Line Formation of the Western District 33 



gulf of the area described, and probably from 600 to 1000 

 feet deep ; but as its activity lessened the cones of eruption 

 formed in the interior, and these having broken out from 

 time to time in new vents, moulded the peaks nearly as 

 they now exist 



Surrounded as Tower Hill is by extinct volcanoes, ranging 

 at various distances from thirty to forty miles — all of which 

 poured out molten lava in abundance — it is somewhat 

 singular that amongst the deposits from Tower Hill there 

 is evidence only of showers of red-hot stones, comminuted 

 basalt, or ash-dust and vapour. The stones are glassy in frac- 

 ture, and are obtained in the sides of the crater and adjacent 

 pastures ; but the ash and the dust and vapour which form 

 the tufa extend around for several miles' distance, but more 

 especially to the south and east in the direction of Warrnam- 

 bool, precisely as if ejected under existing meteorological 

 conditions. It is to the vast volumes of steam ejected, and the 

 heavy rainfalls which would accompany these great atmo- 

 spheric disturbances concomitant with violent eruptions, 

 that I attribute the induration of the sand dunes on which 

 Warrnambool is built into strata of rock bending equably 

 over in the form of mammaliferous hills ; and as each layer 

 or bed of sand became blown over and covered the former 

 layer, fresh precipitation of moisture would dissolve, and the 

 solution would penetrate and cement the loose particles of 

 shell together ; and so the process would continue for such 

 time as Tower Hill continued to eject matter. 



Evidence of the formation of these dunes on dry land is 

 occasionally given by the exposure of the imprint of foot- 

 marks of some three-toed animal or bird, which may have 

 been either emu or kangaroo, the impressions being suffi- 

 ciently distinct as a footprint, walking on sloping ground, 

 but scarcely so clear an impression as to indicate precisely 

 the nature of the animal. 



On the flank of Tower Hill, near Yangery, a shaft was 

 sunk through the layers of ashes and tufa to a depth of from 

 70 to 80 feet and a bed of ancient turf exposed ; but this 

 depth I believe to be a minimum. 



From a careful consideration of all the preceding facts, 

 and from reasoning based on them, I have been able to 

 arrive at only one conclusion, namely, that between Warr- 

 nambool and Yambuk the form of coast line has been 

 determined by the outflow of molten lava ; that three coast 



e2 



