GEOLOGY OF NUNDLE DISTRICT. 105 



is the serpentine belt of Port Macquarie, New South Wales, which 

 runs in a north-easterly direction. Little is known as to the period 

 of intrusion of these rocks. The Tasmanian occurrences are stated 

 to be Devonian in age, the Nundle belt is probably late Devonian 

 or early Carboniferous. Of the rest no more can be said than that, 

 with one exception, none of them have been proved to be of an age 

 not comparable with that of the Nundle and Tasmanian rocks. The 

 exception is the serpentine of Dolodrook, near Mt. Wellington, in 

 Victoria, which is Ordovician or older. Should it be shown even- 

 tually that the Eastern Australian and Tasmanian ultrabasic rocks 

 are in the main coeval, it would indicate that at the time of their 

 intrusion, probably near the close of the Devonian period, the whole 

 area over which they extend was being folded as a geological unit, 

 about an axis running approximate by north-north-west, and south- 

 south-east. The evidence at Nundle suggests that the thrust was 

 directed from the east. 



(Postscript added 3rd June, 1911.) 



Since the above paper was written further study has been made 

 of the Nundle-Bingara serpentine belt, about its northern portion, 

 the Bingara district. . While the sequence of events deducted from 

 a study of the Nundle is fully confirmed, it seems that the period 

 of folding associated with the intrusion of the ultrabasic magma 

 was most probable in late carboniferous times. The periods of 

 diabase intrusion and of sihcification must accordingly be advanced, 

 though both antedate the permo-carboniferous. That the thrust 

 was from east to west is sufficiently clear. 



Further work is now in progress. 



Bibliography. 



The following are the references that bear most directly on the 

 matters here considered : — 



1. Anderson, W. A. : Ann. Rep. Dept. Mines N.S.W., 1888, pp. 179-182. 



2. Andrews, E. C. : " Tertiary History of New England," Rec. Geol. Sur. N.S.W., 1903, Vol. VIl., 



pt. iii. 



3. "Geology of the New England Plateau," parts I., IL, HI. ; Ibid. Vol. VII., pt. iv., Vol. VIII., 



parts 1. and ii. 



4. More recent physiographic notes. 



5. Came, J. E. : Ann. Rep. Dept. Mines N.S.W., 1892, p. 153, 1895, p. 125. 



6. David, T. W. E. : Ann. Rep. Dept. Mines, 1891, pp. 218 and 235. 



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pp. 548, et. seqq. 



8. David, T. W. E., and Pittman, E. F. : " On the Paleozoic Radiolarian Rocks of New South 



Wales," Quart. Journ. Geol. Soc, 1899. 



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logical Survey, 1899. 



10. Dunn, E. J.: "On Mt. Wellington Corundum," Austr -Mining Standard, Oct. 16,1907. 



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Queensland, No. 1, 1904. 



12. Etheridge, R. iunr. : Rec. Geol. Sur. N.S.W., 1899, Vol. VI., pt. 3, pp. 152-182. 



13. Etheridge, R. junr., and Jack, R. L. : " Geologj' and Palaeontology of Queensland," p. 91. 



14. Harker, A. : " Natural History of Igneous Rocks," p. 53. 



15. Jaquet, J. B. : Ann. Rept. Dept. Mines, N.S.W. 



16. Jaquet, J. B. : Ibid., 1897, p. 171. 



17. Jensen, H. I. : Proc. Linn. Soc. N.S.W. , 1906, Vol. XXX., p. 102. 



18. Jensen, H. I. : Proc. Linn. Soc. N.S.W., 1908, Vol. XXXII., p. 701. 



19. Pittman, E. F., and David, T. W. E. : See above. 



20. Pittman, E. F., and David, T. W. E. : " Auriferous Deposits of Lucknow," Rec. Geol. Sur. N.S.W., 



1900, Vol. VII., pt. i. 



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22. Stonier, G. A. : Ann. Rep. Dept. Mines, N.S.W., 1891, p. 261, 1895, p. 168. 



