557 



THE GEOLOGY OF THE WARRUMBUNGLE 

 MOUNTAINS. 



By H. I. Jensen, B.Sc, Linnean Macleay Fellow of the 

 Society in Geolooy. 



(Plates xxiv.-xxxii.) 



Synopsis, 



A. Geology. 



1. IXTilODUCTION 



2. Petrography 



5. Physiographic Notes 



4. Geomorphogeny ... 



(a) Pre-Cretaceous Configuration ... 



(b) Stream-Development 



(c) Peneplanation 



(d) Vulcanism 



(e) Present Changes ... 



-5. Springs and Artesian Water 



'6. Diatomaceous Earths, Coal, Ironstone and Opal 



B. Petrology 



Page. 

 557 

 559 

 565 



571 

 572 

 573 

 575 

 576 

 579 

 583 

 586 



A. Geology. 

 1. Introduction. 



The Wari'umbungle Mountains proper lie about 70-80 miles 

 W.S.W. of Gunnedah, and about the same distance N.N.E. of 

 Dubbo, the two nearest and most convenient railway centres; 

 and between the townships of Coonabarabran, Mundooran, 

 Tooraweanah and Baradine, which are the nearest places where 

 stores and accommodation can be obtained. 



The Warrumbungle Mountain Region is roughly circular in 

 shape, with a diameter of from 30 to 40 miles. 



I spent two months in the district in 1905 (October and 

 November) and nearly two months in 1906 (also October and 



