96- geology of lower mesozoic rocks of queensland, 



Geological History. 



In discussing the conditions which existed during Lower 

 Mesozoic times in Queensland, reference must be made to the 

 conditions, as far as we know them, towards the close of the preced- 

 ing Permian ( Perrao-Carboniferous) Period. The latest sediments 

 of this latter period are the Upper Coal- Measures in both New 

 South Wales and Queensland. In New South Wales, the New- 

 castle or Upper Coal-Measures were formed in a large basin. In 

 an earlier paper,* I have attempted to show, in a general way, 

 the distribution of land and sea in New South Wales during the 

 various stages of the Permian (Permo-Carboniferous)t Period, 

 and have suggested that the successive stages within the period 

 might have been produced by a tangential force acting towards 

 the continental mass of Australia in a W. b}^ S. direction. 



The close of the Palaeozoic era in Northern New South Wales 

 and Southern Queensland was accompanied by extensive intru- 

 sions of granitic masses. In the New England and Stanthorpe- 

 Warwick districts, these intrusions have resulted in extreme 

 folding of the Permian (Permo-Carboniferous) stiata, but have 

 not affected the sediments of the Walloon epoch. The age of 

 the intrusions is definitely between the upper marine sediments 

 of the Permian System and the Walloon Series. The Permian 

 (Permo-Carboniferous) sedimentary strata have been extremely 

 folded and contorted, and converted into slates resembling, in 

 general appearance, rocks of greater age than Permian: their 

 age, however, has been fixed beyond doubt by the occurrence in 

 them of marine fossils in the Drake district, and near Warwick. | 



* Proc. Linn. Soe. N. S. Wales, 1913, xxxviii., pp. 139-145. 



t It has recently been suggested bj^ Professor David and Mr. W. S. Dun 

 (British Assoen. Adv. 8ci., Australia, 1914: Report, p. 379; and Federal 

 Handbook on Australia, p. 267) that perhaps the term Permo-Carboniferous 

 in Australia should be replaced by the term Permian. Without going into 

 reasons here, it maybe stated that the author is entirely in accord with 

 the suggestion, and, for the purposes of this paper, proposes to write the 

 name thus : Permian (Permo-Carboniferous). 



ij: Andrews, "Report on Drake drokl and Copper Field,'' Geol. Surv. 

 N. S. Wales, Mineral Resources, No. 12, 1908. 



