BY H. I. JENSEN. 



857 



Dunmore's place, where T camped (altitude 1,150 feet), has sand- 

 stone cliffs 400 feet high on either side. Higher up the creek 

 cliffs of igneous rock are frequently seen. Ascending the table- 

 land south of Dunmore's the sandstone formation was seen to 

 persist to a height of 1,600 feet, where dark, fine-grained cappings 

 of Eegirine- trachyte or andesite commenced. Much of it is quite 

 scoriaceous. The sandstone north of the creek has a gentle dip 

 to the N.W. at Dunmore's, changing to N.E. as one proceeds 

 upstream. South of the creek it has a gentle westerly dip. 



Between Dunmore's and Deriah Mountain coarsely porphyritic 

 basalts without olivine and andesites cap the trachyte in various 

 places on the tableland at a height of 1,650-1,700 feet. The 

 forest vegetation improves at this level, consisting of box 



{Eucalyptus alhens)^ cedar ( ?), kurrajong {Sterculia diversi- 



folia), watergum {E. rostrata), and wattles. A basaltic crater 

 occurs a couple of miles west of Deriah. Boxtree Gully heads 

 near it (Fig. 8). 



Deriah Creek heads near Deriah ^Mountain, the structure of 

 which is represented in Fig. 7. 



OrRIAH 

 l^oofr (TrachytG.) 



Fig. 7.— Section, in a general E. and W. direction, at Deriah. 



a, andesitic rock; b, trachyte breccia; c, vesicular trachy-andesite; 



r, arfvedsonite trachyte; a, sandstone (Triassic ?). 



The Deriah Mountain trachyte is oldeo-than the fine-grained blue 

 fegirine-nepheline phonolite and phonolitic trachyte which 

 occur under the basalt of the surrounding hills (Figs. 7 and 8). 



At Left Eulah Crag on Eulah Creek, north of Deriah, a large sill 

 of even-grained arfvedsonite-trachyte intrudes the sandstone and 

 forms a bold cliff. In the area lying between Deriah and Eulah 



