72 GEOLOGY OF MT. FLINDERS AND FASSIFERN DLSTRICTS, Q., 



To the south of the area in which all these trachytic mountains 

 occur, and lying between this area and the McPherson Range, 

 there are numerous steep peaks, and ridges, and ranges which 

 are of rhyolitic composition, according to Mr. Wearne, who has 

 shown me beautiful rhyolites and obsidians from this district. 

 The rhyolitic mountains comprise the McPherson Range, Mt. 

 Maroon, the Maroon Range, Mt. Barney, and Mt. Toowoonan 

 (the last-mentioned may be composed of trachyte). It would 

 seem that the period of eruption which gave trachytes in the 

 Fassifr-rn District, gave rhyolites in the McPherson Range area. 

 Pasalts have followed in both areas. 



From Engeisburg, in the Fassifern District, I visited, accom- 

 panied by Messrs. Wearne, McGrath, and Johns, the Little 

 Liverpool Range. We ascended the range along the Old 

 Warwick Road, and reached a point between Spicer's Peak and 

 Mt. Mitchell, about 23 miles from Engeisburg. A section show- 

 ing the structure of the range (not to scale) is given in figl. 



Governors Rock 



Fig. 1. — Diagrammatic representation of the formations met \Yith in 

 ascending the Little Liverpool Range along the Old Warwick Road 



The whole range is apparently due to a gigantic trachyte fissure- 

 eruption, which has emitted flows of light grey trachyte, sheets 

 of breccia and tuff, dark trachytes and trachy-andesites. Later 

 eruptions of a more localised and less intense nature emitted 

 andesite, which in some places has burst through the trachyte. 

 Still later, eruptions simultaneous with those which emitted the 

 enormous flows of basalt on the Darling Downs, gave rise to dykes 

 and sills, intruding also the trachyte. These Darling Downs 



