59 



least with that of their present submergence. (Four hundred" 

 feet actually: known.) 



4. It is highly probable that upheaval was an important 

 factor of climatic change at this period. The relationships of 

 the Post- Miocene faunas and floras of the continent with those 

 of the large adjacent insular masses demand a more intimate- 

 connection with the continental area than that which now ob- 

 tains ; this was probably furnished by elevation of the sea bed. 



5. That the present arid zone of Central Australia was, 

 during the glacial period, a region of copious rainfall, of fresh- 

 water seas, and perennial rivers ; now a barrier to the comming- 

 ling of the south-western and eastern floras and faunas ; it, at- 

 that time, was doubtlessly the line of migration of the eastern 

 species of south-western generic types, and vice versa. 



