156 



Robert A. Kehle: 



From the fact that the lavas of Western Victoria are compara- 

 tively recent, and those of Eastern Victoria relatively old, typical 

 instances of the cross-lateral in all its stages are difficult to 

 .select. Perhaps the confluence of the confined and extensive lava 

 plains to the south of Ballarat provides as good an example of the 

 preliminary conditions leading to the formation of a cross-lateral, 

 -as may be found. (Fig. 10.) 



Softer seof/mentarj POcA g 

 Fig. 10. 



/Resistant /sya f/e/(f. 



Typical conditions for the subsequent development of the cross -lateral 

 junction of confined and extensive lava fields, south of Ballarat. 

 Scale 8 Indies to 1 inch. 



The Hallam Creek furnishes a typical example of a mature crpss 

 lateral, Assisted by the hard rocks at Flinders, which retarded 

 ■all streams seeking an outlet in that direction, strengthened by the 

 rapid and unretarded erosion of the Port Phillip system, and 

 rejuvenated by the Cape Schanck-Dandenong fault, the head-waters 

 -of a stream belonging to the Port Phillip system have cut back to 

 the east of Dandenong, and encroached on and captured all the 

 laterals of the Western Port system up to and including the eastern 

 lateral of the Berwick residual, and possibly even further afield. 

 It has diverted the lateral streams coming from the north, and 

 reversed the direction of their continuation to the south. The 

 streams concerned are the Narre Warren Creek (the original 

 length of which is shown on Fig. 6), two laterals (in part) of the 

 Cranbourne residual, which have been reversed, and some minor 

 laterals. 



