150 R. A. WEARNE AND W. G. WOOLNOUGH. 



(1), of Trias-Jura Age contemporaneous with the Walloon 

 stage of the Ipswich Ooal Measures and including the more 

 normal trachytes of the Main Range, Mounts Edwards and 

 Flinders and the basalts of the Main Range near Cunning- 

 ham's Gap, and 



(2), of Tertiary Age including the more alkaline trachytes 

 of Mounts French and Greville, the rhyolites of Mounts 

 Maroon and Barney, and the basalts of the Toowoomba 

 Range. 



Summary. 



1. At least two levels of erosion are to be recognised in 

 West Moreton, standing respectively at an altitude of 

 2,600 feet and 4,000 feet. 



2. Extensive block faulting has occurred, giving rise to 

 what we have termed the Main Range Fault, the Lockyer 

 Block, and the Fassifern Block. 



3. An area of fossiliferous Permo-Oarboniferous is shewn 

 to exist near Mount Barney. 



4. The volcanic sequence is: — 



i. Trachyte 



ii. Andesites and dacites 

 iii. Rhyolites 

 iv. Basalts 



5. The ages of the volcanic eruptions believed to belong, 



i, to the Walloon stage of the Trias-Jura Coal 



Measures, etc. 

 ii, to the Tertiary Period. 



Fetrographical Notes. 

 Granophyre, Mount Alford. — Allotriomorphic granular 

 rock with very conspicuous granophyric structure, Essen- 

 tial constituents, plagioclase, anorthoclase, quartz, alter- 

 ation products of ferromagnesian minerals, ilmenite and 

 apatite. Exclusive of the granophyric fibres, the average 



