BY E. C. ANDREWS. 789 



age; while upon the same area a still later and comparatively 

 insignificant movement or vibration of elevation has been imposed, 

 criteria of the uplift existing as numerous raised beaches, tombolos 

 and wide coastal plains backed up by high precipitous escarp- 

 ments. 



For the Sydney area we may represent the elevation which 

 attained its maximum importance during the eai^ly part of the 

 canon cycle as 3000 feet, the fluctuating late subsidence as 200 

 feet,"^ and the joggle of elevation as 10 feet. The relative 

 importance of each is thus appreciated. In a short time the thin 

 veneer of coastal plain exposed by the elevatory vibration will 

 vanish from the shore-line topograph}', while under the steady 

 march of marine and subaerial forces the evidence of the epicycle 

 of coastal sinking in late Pleistocene times, although more stable 

 than that of the weaker elevation, will also be found to be short- 

 lived. Yet after their disappearance the geographer will decipher 

 the tale of the great late Tertiary uplift with the greatest ease, 

 though doubtless scores of tremulous movements will modify the 

 topography before the close of the C3'cle. Care should be exercised 

 not to miss the main lesson in the insignificant details; shore-line, 

 shore, coast, and plateau should be surveyed together, and the 

 recent oscillatory movements discussed in the later portion of this 

 pa[»er may be regarded as ephemeral features which influence the 

 grand issue in part only and depend for the very recognition of 

 their existence on the evidence yielded by the associated sedi- 

 ments, as the occurrence of scaffold planks is inferred from the 

 sight of a finished edifice. 



As this paper is written mainly with the object of clearly 

 differentiating between the various divisions of a cycle, let us 

 emphasise the point still further by considering the philosophy 

 of sedimentation as throwing light on the subject. Great systems 

 like our Carboniferous and Permo-Carboniferous show immense 



* More pronounced subsidence with equivalent sedimentation is indicated 

 for North Queensland. 



