174 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.W., 



i. Introduction. 



The material embodied in the following paper, is the result of 

 observations, made at intervals, during the last ten years. A 

 residence of some eight years in Bathurst gave me special facilities 

 to study the geology of the district. During that time I have 

 carefully examined some 180 square miles of country, taking the 

 City of Bathurst as a centre. Although I am conscious the paper 

 deals with nothing that may be regarded by geologists as novel or 

 striking, for all that, it may be acceptable to place on record my 

 observations on a district on which very little has hitherto been 

 written. The present contribution will, I hope, be merely an 

 introduction to the geology of a portion of the country that 

 presents rare facilities for the study of many of the great questions 

 connected with the nature of metamorphism, and the phenomena 

 presented by altered strata in the regions of eruptive rocks. 



The hand-specimens which accompany this paper will help to 

 make clear descriptions of rocks of uncertain affinities. The 

 micro-photographs of rock-slices, on Plate xiv., will also help to 

 illustrate the structure of the basalts. This is all the more useful 

 in the present unsettled state of penological nomenclature. 

 As there is a growing tendency among penologists to follow 

 Professor Rosenbusch's classification of the eruptive rocks, I have, 

 as far as possible, referred the Bathurst rocks to his system. 



There are many interesting questions immediately connected 

 with the geology of Bathurst not touched on in this paper. The 

 contact area, for instance, that forms a fringe of metamorphic 

 rock around the central boss of granite, would demand more 

 knowledge and experience in the refinements of modern petro- 

 graphic methods than I can lay claim to. In fact I have stu- 

 diously avoided, or merely pointed out, debatable questions. But, 

 having described what almost all geologists are agreed on, the way 

 is clear in the future to deal with the more obscure, but possibly 

 the more interesting, problems that may be studied in and around 

 Bathurst. In dealing with the microscopic structure of the basalts 



