RY C. HEDLEY. 321 



Til conclusion, the Boiidi anticline is suggested as the medium 

 of that tremendous driving force which thrust down the l)asin 

 now outlined by the Wianamatta shale, till the Prospect la\a 

 squirted through its broken floor, displaced the Hawkesbiuy 

 liiver from Camden to Windsor, and pressed up the Blue 

 Mountain ridge behind. The giant fold, of which it was a part, 

 relaxed its grip and died in its youth, as the anticline cracked 

 and burst. 



EXPLANATION OF PLATES XXV.-XXVIL 



Plate XXV. 

 Scheme of an anticline deduced to match the Blue Mountain ridge and 

 the Pairamatta trough, and to account for the disturbed .shales and sand- 

 stones about Sydney. From the paths of the radial dykes it is developed 

 as a crescent directed west and swollen medially near Bondi. Based on 

 the Geological Sketcii Map of Sj'dney, Dept. Mines, 1903. 



Plate xxvi. 

 Example of a crumpled sheet of shale regarded as entangled in a slide 

 of the sandstone-beds. Opposite Cremorne Wharf, Milson Road in the 

 foreground. Drawn l)y Miss P. Clarke. 



Plate xxvii. 

 A series of coils of sandstone which, it is presumed, were slowly rolled 

 up and together when a superincumbent mass of rock was launched across 

 them. From the road side, between Seaforth and the Spit, east side of 

 Middle Harbour. Photographed by Dr. H. G. Chapman. 



