202 VOLCANIC ROCKS OF SOUTH-EASTERN QUEENSLAND 



Fig. II. — Geological sketch-section iu a general north-west 

 direction from MacPherson's Eange to the 

 Albert River, north of Tamborine Plateau. 



Fig. III. — Geological sketch-section north and south 

 through ]\Iount Lindsay. 



Fig. IV. — Geological sketch-section east and west through 

 Lamington Plateau. 



These sketch-sections show clearly the relationships of 

 volcanic rocks to the Mesozoic and Palaeozoic rocks, the 

 thickness of the volcanic rocks, and also the relative thick- 

 nesses of the upper, middle, and lower divisions of volcanic 

 rocks in different places. 



Plates XII. -XIV. 



Micro-Photographs. 



All the micro-photographs are x 30. and in ordinary 

 light except where otherwise indicated. 



Plate XII. 



Fig. 1. — Pitchstone from Mount Lindsay, showing fluxion 

 structure around a phenocryst of felspar. The 

 felspar shows corrosion and a partial replace- 

 ment by the brown glassy matrix. Sp. 228. 



Fig. 2. — Perlitic pitchstone, Glass Cutting, Springbrook 

 Plateau. Sp. 135. 



Fig. 3. — Pitchstone, Moogerah School, near ]\Iount Alford. 

 It shows spherulites, axiolites and a phenocryst 

 of felspar. Sp. 20x. 



Fig. 4.— Rhyolite. Mount Lindsay. X nicols. Sp. 223. 



Fig. 5. — Rhyolite, ]\Iount Barney, showing micrographic 

 structure. X nicols. Sp. 220. 



Fig. 6. — Rhyolite, S.E, of Tamborine Plateau, shows micro- 

 spherulitic structure. X nicols. Sp. 54c. 



