Hill was accompanied by a warping of the plateau to a 

 height of less than 300 feet at Sydney, while to the north 

 and north-west around the lower course of the river the 

 plateau was carried to a height of over 700 feet. South- 

 ward also the plateau was rapidly carried to a height 

 exceeding 2,000 feet. Moreover this lower central portion 

 was composed in the main of soft Wianamatta shales, 

 while the more uplifted masses consisted of heavy and 



Another point of interest is that the monoclinal fold is 

 almost intact, its mass lias not been severely breached 

 as yet, except where large watercourses cross its line of 

 direction. The small trench (Knapsack Gully) crossed by 

 the western train in ascending the scarp between Emu 

 Plains and Glenbrook, gives a good idea of the extremely 

 youthful stage of its dissection. 



Significance.— The late and Post-Tertiary history of the 



A peneplain was developed in eastern Australia id 

 Tertiary time. The Pleistocene was ushered in (as shown 

 in a previous chapter) by flexing and folding and a great 

 coastal strip was faulted and flexed parallel to the shore 

 line. Against the eastern wall of an upfaidted block to 



commenced to cut its way into the rising ground. Along 

 the lower 100 miles of its course it appears to have had a 



at present, and as the land was warped athwart its course 

 tli" riv.-r maintained its channel against the rising ground. 

 Had this not been the ease, the ,„•,;„„ must have surely 



