H'njhhtiuJs i)f Wt'stmi Victor HI. 253 



tunately fcir the ;ir<jruiiiLiit tlit- Murray c<.'ls turn out on investiga- 

 tion to be either lampreys or importations, thouprh it is quite in 

 accordaiu'e with the known habits of eels to wrip^rle across the 

 Divide occasionally, as they can travel some distance on land 

 durinp: heavy rains. The mao:]iie is scarcely worth considera- 

 tion in this connection ; it can, fly across the Divide if it likes 

 If one variety is northern and the other southern, there is 

 nothing to keep either exactly in its place. In spite of any- 

 thing that can be said, the fact remains that there is a greater 

 diflference between the jilants and animals of northern and 

 southern Victnria than there is between those of southern Vic- 

 toria and Tasmania.^ This is all the more remarkable when 

 we comider the Divide closely. Differences in climate and soil 

 ha/ve a large share in producing this result, but we can only 

 explain its importance in this respect by considering it a Divide 

 which has been much longer established than Bass' Strait. 



There is little doubt, however, that Ba>s' Strait dates from 

 within the human period in Victoria. 2 



The .Main Divide, from a geographical point of A-iew, is a 

 watershed line of composite character between the north and 

 south flowing streams. Biologically it is an area of highlands 

 sufficient to offer some direct obstruction to the migration of 

 ])lants and animals, and to establish a climatic difi'erence which 

 further affect*; their distrilmtion. Commercially and indus- 

 trially it is important, not only for this climatic difference, but 

 because it is a suihcient barrier to have determined trade routes 

 by its easiest passes. Politically it has become incorporated as 

 a boundary line of districts in much of our administrative 

 system. 



I propose now to consider the character of the Avestern high- 

 lands as a whole, then of the Divide as we now see it, then its 

 origin and early history. 



The rocks of the western highlands are for the most part 

 coloured as Ordovician on the geological maps, though direct 

 evidence of fossils has not vet been obtained over the greater 



1 A. H. S. Luc^as, " On some facts in the f!eoi,''rap)iical Distribution of Land and Fresh- 

 water \ertel)rates in Victoria." l^roe. lloy. Soe. Victoria, IX., new series, 18ft7. 



2 A. W. Howitt, Aiistralasiaii .Association for the Advancement of Science, Sydney, 

 1898. Presidential Address, Section G. 



