13Y H. I. JENSEN. 497 



liad been worn down so as to expose deep-seated intrusive bodies. 

 Subsidence or transgressions of the sea followed in many places 

 and Permo-Carboniferous sediments were laid down east of the 

 continental masses. At this time commenced a new period of 

 volcanic action ushering in the era of continental extension in 

 the area of heavy Carboniferous and Permo-Carboniferous sedi- 

 mentation, and the worn-down continental areas to the west were 

 exposed to Mesozoic marine transgressions. 



During this pyrogenic period most of the New England 

 granites were intruded, as shown by C. E. Andrews.* In other 

 parts gigantic basaltic flows took place, as, for example, the lavas 

 of the Kiama-Jamberoo series. This period of volcanic activity 

 ■ended with the eruptions evidenced by the tuffs in the passage 

 beds between the Permo-Carboniferous and Triassic. 



Some of the lavas of this period were rather inclined to be 

 alkaline. 



4. Neopyrogenic— Andrews* has shown that in the New 

 England district the intrusions svere followed by a long period 

 of plateau-dissection and peneplanation. Meantime steady 

 sedimentation took place in the Triassic-Cretaceous basin to the 

 west. During Cretaceous times there was probably a general 

 lowering of the land-level throughout Australia. The close of 

 the Cretaceous was signalised by a renewal of volcanic activity, 

 of which Maitland found evidence in the trachytic tuffs of the 

 Desert Sandstone, near Mackay, Queensland.! 



Andrews considers the latest granites of New England to be 

 possibly as late as the Cretaceous. I have myself found granite- 

 porphyries and diorite-porphyrites (cp. the Noosa Head porphy- 

 rite), in the East Moreton district, Queensland, which are 

 distinctly Post-Triassic. J 



• "Geology of the New England Plateau." Records Geol. Survey, 

 N.S.W. Part i. Physiography, in Vol. vii.: Parts ii. and iii. The Granites, 

 in Vol. viii.; Part iv. Petrology, in Vol. viii. 



t Geological Features and Mineral Resources of the Mackay District. By 

 Authority, Brisbane, 1889. 



£ Note on a Glaucophane Schist from the Conandale Range. Proc. Linn. 

 Soc. N.S.Wales, Vol. xxxii., p. 701. 



