SHORELINE STUDIES AT BOTANY BAY. 175 



have been formed independently of the bedding planes. 

 Especially well is this feature shewn at certain points near 

 Sydney as at Long Reef, examined in 1916 by Dr. H. E. 

 Gregory of Yale, Mr. J. E. Oarne, State Government Geo- 

 logist, and the writer. These platforms vary in width 

 from a few yards to as much, perhaps, as 150 or 200 yards. 

 They are awash at high tide. The cliffs have been ex- 

 cavated in sandstone and tough shales and they are well 

 subdued forms with a moderate thickness of soil and sub- 

 soil beneath, through which the rock structure is visible 

 only in a few places of insignificant size. Trees also of con- 

 siderable age are growing thereon. The general appear- 

 ance of the exposures indicates that for some reason the 

 sea has not sapped these subdued slopes for a hundred years 

 if not much more. In addition to this evidence, it may be 

 mentioned that certain of the more vertical cliffs in the 

 hard sandstone around Sydney overlook rock platforms 

 lying above high water mark. These cliffs have their 

 bases cumbered with heavy rock masses which have fallen 

 from the cliffs above. So high out of the water and so 

 heavy are these fallen masses that they were not moved 

 by the 1912 storm, neither indeed do the great storms of 

 1889 nor 1876 appear to have moved them. These plat- 

 forms are at such heights that heavy storm waves could 

 not have carved them during the period which the sea has 

 stood at its present level, seeing that the action is not 

 due to benching, but to actual truncation of rocks dipping 

 gently inland, and moreover, a low cliff of submarine erosion 

 forms the seaward aspect of the bench or terrace. The 

 present position of these benches of marine erosion can 

 be explained satisfactorily only upon the assumption of a 

 recent and slight emergence of the land. 



Inasmuch as Lady Robinson's Beach is centred among 

 all these emerging features, it may be explained, therefore, 

 as a beach formed upon a set of shoals which have emerged 



