252 THE ANTIQUITY OF MAN IN TASMANIA. 



were to recede 300 feet, we would have about the land as 

 it appeared in post-glacial times. 



A receding of the sea level for 300 feet corresponds 

 with the 50-fathom line. On the eastern coast of the 

 isthmus the 50-fathom line is monotonous and not inter- 

 rupted by any bays, but on the western coast we per- 

 ceive a number of deep bays. The largest bay is found 

 between 39deg. and 4odeg. lat., and I43deg. to I44deg. 

 long. A little further south there are three more bays, 

 and further south still the 50-fathom line comes close 

 on to the present coast Hne. 



The whole appearance of the bays above-mentioned 

 is such that they probably represent the mouth of old 

 rivers coming from the north-east. 



Now, let us assume that the sea level having receded 

 to the 50-fathom line, and the basin of subsidence be- 

 tween Tasmania was not in existence. The south-east 

 corner of Australia would then represent a large pointed 

 peninsula, reacliing almost to 44deg. lat. (i). It is ob- 

 vious that under these circumstances the course of rivers 

 from the north of Tasmania and from the southern coast 

 of Victoria, in particular those east of Wilson's Promon- 

 tory, must have been different from what it is to-day. 



The rivers from Tasmania will have continued to run 

 towards north, and those from Victoria towards south, 

 till the two systems met, probably forming one large 

 stream running in south-western direction across the 

 peninsula. Traces of these old river courses are still 

 preserved in the submarine contours of Bass Strait, the 

 40-fathom line showing them particularly well. The in- 

 dented course in its eastern portion indicates the course 

 of the old rivers, and the deep channel which runs in 

 south-western direction represents most probably the 

 course of this ancient river. 



This hypothesis is strongly supported by another fact. 

 Hitherto it has been rather a mystery to account for the 

 strange similarity that exists between the fauna of the 

 rivers in southern Victoria and northern Tasmania. Mr. 



(i) Australia would have a strange likeness to present Africa, 

 ■ during that time. 



