8G0 GEOLOGY OF GLASS HOUSE MTS. AND DISTRICT, 



Greater denudation of the Triassic has taken place in the 

 Blackall Range area, where sedimentation had been greater, and 

 subsequently re-elevation more considerable. 



That the eastern coast of Australia is undergoing a wave-like 

 movement tangential to shore-line is rendered probable by the 

 evidence afforded by numerous submerged forests and raised 

 beaches along our coasts. Folding from the X.W. in New South 

 Wales and from the S.W. in Queensland would explain such a 

 tangential movement, the focus from which folding proceeds 

 underlving the New England Tableland and the McPherson 

 Range. "^^ 



Tidal action extends in the meandering Caboolture River as far 

 as Wararbah Creek, and larger streams like the Caboolture and 

 Stanley rivers have undoubtedly captured the drainage areas of 

 other streams which are now represented by creeks and swamps. 

 This indicates long-continued stable conditions, or at any rate 

 extremely sloiv change of level. Sandy bars occur at the mouths of 

 all the creeks and rivers. Yet it would be extremely risky to draw 

 inferences from these features, as, on account of the soft nature 

 of the Triassic bedrocks, and the vehemence of Queensland floods, 

 it does not take a river very long to carve a course for itself in 

 this region, and those rules which hold for hard Palaeozoic forma- 

 tions can in this case only be applied with extreme precaution. 



V. Petrology. 



The subject of the petrogra.ph}- of the Glass House Mountains 

 rocks, the writer proposes to discuss in greater detail in a future 

 paper. 



An idea has already been given of the sedimentary rocks of 

 the district, which comprise : — 



1. The Palieozoic slates and schists referred by Queensland 

 geologists to the Gympie Formation. 



* Of. Suess' Theory on "The Parallel Grouping of Mountains round 

 Ancient Coasts " in 'Das Antlitz der Erde. ' 



