Vol. 50.] THE GEOLOGY OF BATHURST (NEW SOUTH WALES). 105 



9. The Geology of Bathurst (New South Wales). By W. J. 

 Clunies Boss, Esq., B.Sc, F.G.S. (Bead November 8th, 

 1893.) 



Contents. 



Page 



I. Introduction 105 



II. Previous Work on the Subject 106 



III. Physiography of the District 106 



IV. Detailed Geology of the District 107 



1. The Central Area. 



2. The Age of the Granite. 



3. The Silurian Rocks. 



4. The Devonian Rocks. 



5. Rocks newer than the Devonian. 



6. The Later Tertiary Rocks. 



V. Summary 117 



Map and Section 108, 109 



I. Introduction". 



Bathurst may be regarded as the centre of a district of considerable 

 geological importance, not alone as an isolated area in the Australian 

 colonies, which might be considered of merely local interest, but 

 because of its relationship to other areas. The solution of the 

 problems connected with its stratigraphy and petrography may, 

 therefore, contribute in no small degree to decide the age and 

 relative positions of many of the older rocks of New South Wales, 

 and enable us to correlate them with those of Victoria, on the 

 one side, and Queensland, on the other. 



The late Bev. W. B. Clarke, F.B.S., long ago pointed out the fact 

 that all the older stratified rocks of Eastern Australia have a general 

 north-and-south strike, which can be traced from Victoria, through 

 New South Wales, to Queensland. This important generalization is 

 the key to much of Australian geology. When we ask, however, what 

 is known of the relationship of the rocks of the various colonies, 

 or even of different parts of the same colony, it must be admitted 

 that much still remains to be done. 



In Victoria, it is true, rocks belonging to the Lower and Upper 

 Silurian have been recognized, and a thick series in Gippsland has 

 been classed as Lower, Middle, and Upper Devonian by Mr. A. W. 

 Howitt, E.G.S. In New South Wales the distinction between 

 Silurian and Devonian rocks has not been so clearly made out, and 

 over a large area the strata have been provisionally classified as 

 Siluro-Devonian. Moreover, while there is uncertainty as to the 

 base of the Devonian system, there is also a good deal of doubt as to 

 its upper limit ; and it has been suggested that many rocks formerly 

 classed as Devonian should be placed in the Lower Carboniferous. 



Both Silurian and Devonian rocks are well developed in the 

 neighbourhood of Bathurst, where they form two very distinct 

 series, and as many of them are similar in character and fossil 



Q. J. G. S. No. 198. i 



