RECENT MARINE EROSION AT BONDI. 155 



area, and the sources of the Namoi, Peel, Macleay, Manning 

 and Hunter Rivers. 



Western Slopes and Plains. — These consist of excessively 

 fertile slopes and plains of chocolate, red and black soil. 

 These have been derived from the denudation both of the 

 New England basalts and the fertile Devonian and Carbon- 

 iferous tuffs. 



The writer believes that here will be large centres of 

 population in the future, as a knowledge of the produce 

 adapted to the climatic and soil conditions of this vast area 

 is alone needed for success. 



Note on some RECENT MARINE EROSION at BONDI. 



By C. A. SUSSMILCH, F.G.S. 

 [With Plates IV -VI.] 



[Read before the Royal Society of N. S. Wales, September 4, 1912.1 



On the 15th July of this year (1912) an unusually heavy 

 sea, caused by a storm some distance away in the Tasman 

 Sea, did considerable damage to jetties, breakwaters, 

 retaining walls, etc., along the coast of New South Wales. 

 Some very striking results were produced at Bondi by the 

 waves during this storm and are worth recording. In 

 Plate IV is shown a huge block of sandstone thrown up by 

 the waves at the foot of the headland on the northern side 

 of Bondi Bay near Sydney. This block measures approxi- 

 mately 20 feet long, 16 feet wide and 10 feet high; it has 

 therefore a cubical content of 3,520 cubic feet, and assum- 

 ing that 15 c. ft. of sandstone weigh 1 ton, its total weight 

 must be about 235 tons. It was situated originally at the 



