THE GEOLOGY AND PETROGRAPHY OF THE CLARENCETOWN- 

 PATERSON DISTRICT, Part ii. 



Tectoxic Gbology and Physiography. 



By G. D. Osborne, B.Se. 



[Read 25th October, 1922.] 



General Tectonics of the Area 519 



Faulting 522 



General Considerations concerning the Faulting and Folding 525 

 Structural Relations between the Kuttung Series and the 



Permo-Carboniferous System 526 



Physiography 523 



A detailed account of the stratigraphical and regional g-eology of the 

 Clarencetown-Paterson Disfrict was given in Part i. of this series (Osborne, 

 1922). From the matter there presented, certain tectonic features were implied, 

 but no details of the very interesting structures developed in the area were 

 given. It is the purpose here to describe these structures and the local physio- 

 graphy in detail, the description of the former being a contribution to the 

 knowledge of the tectonics of Eastern New South Wales and of the latter in- 

 dicating the important influence exerted by the arrangement of the strata ui^on 

 the evolution of the topography. 



In addition to acknowledgments already made, the writer desires to thank 

 Dr. Leo A. Cotton, Dr. W. R. Browne and Mr. C. A. Sussmileh for help in 

 discussion on the points specially dealt with below. 



General Tectonics of the Area. 



The broad structural features comprise two irregular plunging anticlines and 

 their complement, an asymmetric plunging syncline, which have been extensively 

 faulted. It will be convenient to name these features the Paterson and Williams 

 River anticlines and the Dunn's Creek syncline. The individuality of these 

 three units is best displayed in the southern part of the area and as one goes 

 north it is found that the warps smooth themselves out and merge into a more 

 unified surface constituting a dome-like structure, the core of which exists some- 

 where about Hilldale or Welshman's Creek. Very little is known of the tec- 

 tonics to the north, but it is evident that the simple dome-like bulge round about 

 Hilldale gives place to more complicated folding northwards, the small syncline 

 shown on the map near Wallarobba forming part of this folding. 



The plunging anticlines are not simple, regular structures, but, as is the 

 ease of most plunging folds, possess a number of irregitlar bulges and local de- 

 pressions which give rise to some interesting forms of outcrop where dissection 

 is fairly well advanced. The extent of the three folds may now be briefly given. 



