Lava Residuals. 



135 



conclusions arrived at in this' paper how the lava was extravasated, 

 or whether the crustal movements responsible for it were of the 

 mountain or plateau building types. What is more important 

 from the standpoint of the physiographer and palaeographer is to 

 reconstruct the lava field as it was at tlie cessation of volcanic 

 activity, and only volcanic phenomena essential to this reconstruc- 

 tion are considered. The Older and New Basalt residuals afford, 

 it is submitted, the necessary data for this reconstruction. 



Pre-Older Basalt cycles of Western Port and Port Phillip. 



Portion of the Western Port system during the Pre-Older Basalt 

 cycle was, as it is now, a mountain region. The same factors that 

 made it so then are in operation now, namely, highly resistant 

 metamorphic rocks at the contact of Palaeozoic granitic and 



Fig. 3. 



New basalt valleys of pre basalt cycle. These valleys were infilled with the older basalt 

 which precipitated the intermediate cycle. 



