PRESIDENTIAL ADDRESS. 37 



the Oanobolas through those of the Warrumbungle moun- 

 tains to those of the Nanclewar Ranges. 



The trend of this great alkaline belt and its prolongation 

 in Queensland through the Macpherson Range, Cunning- 

 ham's Gap, and the Glasshouse Mountains on to Yeppoon, 

 near Rockhampton, and thence to Clermont, has been well 

 shown by Dr. H. I. Jensen. 1 The trend of the Oanobolas 

 to Nandewar line is about N. (true) from the Oanobolas to 

 the Warrumbungles, and N. 35° E. from the Warrumbungles 

 to the Nandewars. The line of trachytic eruptions is pro- 

 longed in a S.S.W. direction from the Warrumbungle moun- 

 tains to the Gibraltar Rock near Dubbo. 



As regards now the chief tectonic lines in the great 

 central coal-field, there are two well marked directions, 

 the first set running more or less parallel to the general 

 axis of the trough in which the basin lies, (in the Lower 

 Hunter district this is shown by the Greta etc. faults, 

 running from between E. 30° S. and E. 10° S. to W. 30° N. 

 and W. 10° N., in the southern coal-field they trend in a 

 general E.S.E. and W.N.W. direction). In this first set of 

 faults the throw in each case is in towards the centre of 

 the basin. The other set of faults runs more or less parallel 

 with the coast line. A well marked trend belonging to 

 this set, is the flat asymmetrical anticline forming the 

 eastern escarpment of the Blue Mountains. This was 

 referred to by me in previous papers to this Society. 2 The 

 general trend of this fold is N. 15° W. (true). It is to be 

 noted that this structure makes an angle of nearly 35° with 

 the fold of the continental shelf. It cannot therefore be 

 correctly described as a parallel structure. The continental 

 shelf has been ably described in detail by Hedley. 3 



1 Proc. Linn. Soc. N.S. Wales, 1908, No. 131, pt. 3. 



2 This Society's Journal, Vol. xxx, 1896, pp. 33-41; Vol. xxxvi, 1902, 

 pp. 399 - 370, pis. xvi, xvii. 



s Presidential Address, Proc. Linn. Soc, 1909, and ibid. 1910. 



