568 THE GEOLOGY OF THE WARRUMBUNGLE MOUNTAINS, 



runs N.N.W., gradually diminishing in altitude, until it is lost 

 in tlie Pilliga Scrub to the N.W. of Baradine. The Warrum- 

 bungle Range has only an average height of about 2,000 feet, 

 and is composed essentially of sandstones, conglomerates and 

 shales which belong to the Triassic to the north-west and north 

 of Coonabarabran, but to the east and south-east they probably 

 belong to the Permo-Carboniferous (Upper Coal Measures). 



The highest peaks of the Warruinbungle Mountains themselves 

 attain an altitude of about 4,000 feet. In the centre of the 

 group we have Wombalong (4,210), Terra Terra (3,710), The 

 Bluff(about 4,000), Mt. Caraghnan(3,875), Berum Buckle (3,710),. 

 and Belougery Split Rock. Practically situated on the Warrum- 

 bungle Range, where it approaches most closely to the centre of 

 the mountain group, are the high peaks of the Siding Spring 

 Mountain (about 4,000), Mobara and Bulleamble. Mt. Bullo- 

 way, at the commencement of the Kalga Range, is apparently 

 also about 4,000 feet high."^ 



The zone of table-topped mountains and spurs of dark trachyte 

 and plionolite surrounding the central mass attains usually to the 

 height of from 2,000 to 2,500 feet. Thus Timor Ledges, north 

 of Timor Rock, are 2,400 feet high. Black Mountain and Naman 

 Ledges 2,500-2,600, Gowang Tableland 2,200-2,500 ; Kalga 

 Range, Paddy McCulloch's Mountain and the Bugaldi Ranges- 

 reach 2,000-2,500 near the Bugaldi-Tenandra Road, but drop to- 

 lower levels further northward. 



In the valleys between the mountains are numerous smaller 

 knobs, steep-sided plugs and sugarloaf-shaped cones. These are 

 particularl}^ abundant in the Gumin-Gumin Valley; Plate xxviii» 

 illustrates their appearance. 



The level at Coonabarabran is about 1,700 feet. At Rivers- 

 dale, 10 miles or so to the S.S.E., it has fallen to about 1,400 



* The elevations given in this paper can only be taken as approximate,, 

 being based on aneroid measurements checked by comparisons with the 

 official barometric readings taken at Coonabarabran, for which I am indebted 

 to the Postmaster. The altitude of Coonabarabran was taken to be about 

 1,700 feet. 



