490 



THE GEOLOGY AND PETROLOGY OF THE GREAT 

 SERPENTINE BELT OF NEW SOUTH WALES. 



Part I. 

 By W. N. Benson, B.A., B.Sc. 



(Plates xx.-xxi.) 



Introduction. 



The Great Serpentine Belt of New South Wales is one of the 

 most remarkable features to be encountered in the study of the 

 palaeozoic geology of the State. Its presence has been known for 

 many years, owing to the association of the serpentine with 

 mineral deposits of economic value, and the outlines of several 

 occurrences were roughly shown in the first official geological map 

 of 1875, based mainly on data collected by the late Rev. W. B. 

 Clarke. Chief among those who have reported on various portions 

 of this belt, have been Messrs. Anderson(l), Clarke(2), David(3) 

 Jaquet(4), Odernheimer(5), Pittman(3), Stonier(6), Stutchbury(7), 

 and Ulrich(8), but lack of opportunity prevented any of these 

 writers from making a detailed study, or attempting any 

 well-founded generalisations. Mr. W. Anderson(l) has given 

 the only petrographical account of the ultrabasic rocks (1888), 

 while to Mr. G. A. Stonier(6) is due the suggestion of the Upper 

 Carboniferous as the era of the intrusion of these rocks (1895). 

 The tectonic complexity of the associated formations, their great 

 thickness and similarity over wide areas, and also the dearth of 

 determinative fossils, has led to conflicting estimates of their age 

 and relationships, perforcedly based on insufficient data. A great 

 advance was made in 1899, in the recognition, by Professor David 

 and Mr. Pittman, of a great thickness of radiolarian jaspers, cherts- 

 and tuffs associated with Middle Devonian coral limestones. Apart 

 from these investigations, the area might be considered virgin 

 ground. 



