16 Evidences of a Glacial Epoch in Victoria 



that half of the globe were swamped, whilst the sea drained 

 off the shallower littoral of the other, converting large areas 

 of sea bottom into dry land. 



Dr. Croll goes further, and taking the present rate of 

 sub-aerial denudation as a measure of time, shows that there 

 are excellent grounds for believing that the period of 

 eccentricity just referred to corresponds with the last glacial 

 epoch in the Northern Hemisphere, which occurred towards 

 the close of the tertiary and the commencement of the 

 quaternary periods, that is to say, during post-miocene 

 times. 



But if the Northern Hemisphere passed through a glacial 

 period about that time, the Southern cannot have escaped ; 

 and the only question to be discussed to-night is whether 

 Victoria was or was not within the range of its rigours. 



Now, geologists have determined the range of glaciation 

 in the Northern Hemisphere so well, that their conclusions 

 will afford us great help in ascertaining the range of 

 glaciation here. 



Croll and others find that the polar ice-cap must have been 

 two and a half miles thick at the least, and that it was 

 probably vastly more, perhaps as much as twelve miles 

 (G. and T., pp. 377-81); that the ice was two and a half miles 

 thick in Canada, and 2000 feetdeep over Scotland (C.and T., p. 

 452). One vast ice-sheet covered all Europe down to the lati- 

 tude of the Thames ; while far southward of 52 degs. N. lati- 

 tude every mountain had its glacier system. The equatorial 

 margin of this ice-cap was as irregular as an isothermal line 

 on a chart, and in places it overlapped latitudes corresponding 

 to that of Melbourne (Great Ice Age, p. 457). Therefore, there 

 is nothing unlikely, in itself, in the statement that Victoria 

 has been glaciated ; and its probability is increased when we 

 remember that all the lower lands of Australia must then 

 have been submerged, whereby the northern interior, which 

 now serves as a warming pan to our atmosphere, was 

 exchanged for cool sea- water ; that the north-west anti-trades 

 would then be stronger and moiwter, and the south-west 

 Antarctic Ocean drift would then be stronger and colder ; that 

 then every zone of temperature must have been shifted 

 equatorward at least 10 degs., so that the wet west winds 

 which now circulate below 40° S., and which feed the 

 glaciers of New Zealand and Patagonia, would then blow 

 up to 30° S., soaking with rain or mantling with snow the 

 islands of Australia. For then Australia, partially sub- 



