BY H. C. RICHARDS. Ill 



The most prominent features of the area are, perhaps, 

 the plateaux capped with basic volcanic rocks in the south. 

 One finds there the extensive plateaux known as Lamington, 

 Rol)erts. Springbrook and Tamborine Plateaux. While 

 slightly undulating on the surface, the first three plateaux 

 rise gradually to the south, and on the border the culmi- 

 nating peaks are approximately 3,500 feet high, while 

 Tamborine plateau is only 2,000 feet high. There is little 

 doubt that they were at one time all connected. They are, 

 however, very much dissected by the head waters of the 

 Logan. Albert and Nerang Rivers and in the upper por- 

 tions of the streams great canyons with almost precipitous 

 sides and nearly 2,000 feet deep in some places occur. 



All along the south-west and west parts of the area, 

 one finds the basalt-capped plateau which constitutes the 

 eastern edge of the Darling Downs, and at a height of 

 approximately 2,500 feet. The main portion of the area 

 is occupied by the slightly undulating Alesozoic plains 

 Avhich are traversed by sandstone ridges in a north and 

 south direction. These are now either capped with volcanic 

 rocks, or show signs of having been covered at one time. 

 The valleys are wide and very deeply filled with alluvial 

 material derived from the volcanic-capped plateaux at the 

 heads of the streams. The outstanding masses of acid and 

 sub-acid rocks form a conspicuous feature, and a close 

 similarity of appearance characterises these masses, e.g., 

 M'ounts Lindsay, Barney, Maroon, Edwards, Greville, 

 Flinders &e., and the various peaks of the Glass House 

 ^lountains. These masses range from 4,600 feet above 

 sea-level in the case of Mount Barney, to small hillocks. 

 The contrast between these peaks of rhyolitic and trachytic 

 rocks, and the plateaux of andesitic and basaltic rocks, 

 is most marked. The western part of the area is bounded 

 by a basalt-capped plateau at a height of about 2,500 

 feet above sea-level, but which has along it several peaks 

 about 4,000 feet high — namely, Mounts Wilson, Roberts, 

 Huntley. Spicer, Mitchell, Cordeaux, Castle &c. On 

 the eastern side, along the coast, there is a broad coastal 

 plain only a few feet above sea-level, extending from 

 near Point Danger to w^ll north of Southport. This 

 is here and there dotted hj inliers of Palaeozoic schists, 



