BY H. I. JENSEN. 625 



LIST OF ILLUSTRATIONS. 



Plate xxiv. 



Sketch Map of the Warrumbungle Mountains, showing Geological Formations. 



Plate XXV. 

 Stereogram of the Warrumbungles. 



Plate xxvi. 



Fig. 1. — View of the BuUeamble Mountains from Siding Spring Mountain, 



showing clififs of columnar lava. 

 Fig. 2. — View of The Spire (Tonduron) from Needle Mountain, showing 



maturity of arid erosion. 



Plate xxvii. 



Fig. 1. — View of the Needle and mountains of continually diminishing 



altitude behind it, overlooking Gowang Station from Needle 



Mountain. 

 Fig. 2. — View of Siding Spring Mountain looking northward do%vn the 



Bugaldi Valley towards the Pilliga Scrub. Note the gradual 



decline in altitude. 



Plate xxviii. 



Fig.l.— View of Bugaldi Valley and Wheoh Mountain from Siding Spring 



Mountain. 

 Fig. 2. — View looking across "Wombalong Valley towards Belougery Split 



Rock, The Bluff, and Mount Exmouth (on the right) from Siding 



Spring Mountain. 



Plate xxix. 



Fig.l. — General View of the Warrumbungles looking north from Needle 

 Mountain. Siding Spring Mountain lies on the extreme left ; 

 Mobara Rock and High Peak in the centre, and Mt. Blackheath 

 on the right. 



Fig.2.— A Sandstone " Mesa " near Baradine Creek. 



(Magnification of microphotographs about 21 diameters in each case.) 

 Plate XXX. 



Fig.l. — Arfvedsonite Trachyte (W.17), Timor Rock, Nicols uncrossed. 



The large black patch consists of an inclusion of shale or schist; 



the rest consists of arfvedsonite (black specks) and anorthoclase 



(white). 

 Fig.2. — Same as fig.l. Nicols crossed. 



