BY H, I. JENSEN. 853 



carbonaceous shales and conglomerates. The sills frequently 

 locate waterfalls in the creeks. 



The country between Mount Odin, Rocky Creek Gap, and 

 Oakey Creek is very broken, consisting of dark green porphyry 

 sills and trachyte porphyry sills intruding Permo-Carboniferous 

 sandstones and shales with Glossopteris. Nearly all the hills 

 have cappings of vesicular trachyte. 



Further up Oakey Creek, about a mile above its junction with 

 BuUawa Creek, massive syenite (akerite) is met with on both 

 sides. This rock has a pepper-and-salt colour, and would make 

 a beautiful building stone. 



Some of the dark syenite-porphyry sills contain angular and 

 rounded included masses of nepheline phonolite, which seem to 

 be fragments of the already cooled magma torn off the walls of 

 the lava-reservoir in the upward passage. 



Oakey Creek contains pebbles of dark syenite-porphyry, grey 

 (pepper-and-salt) syenite, red syenite, essexite, segirine trachyte, 

 88girine phonolite, red trachyte, trachyte porphyries, basalt and 

 basalt porphy rites; therefore all these rocks must occur in the 

 area which it drains. Grey syenite (akerite) covers a large area of 

 rugged country between Oakey Creek and Upper Bulla wa Creek. 

 The occurrence of pine higher up the range under Pound Mountain 

 shows that the syenitic mass has a sandstone capping. Above 

 the sandstone on Pound Mountain and the Nandewar Range in 

 general there is a capping of vesicular volcanic rocks. 



The upper part of the Bullawa Creek (that is above its junc- 

 tion with Oakey Creek) cuts through great igneous masses of 

 trachyte and trachyte porphyry. Very little sandstone is se5h 

 in the area. Here and there a small remnant may be noticed 

 high up on the mountain sides, and may be taken to represent 

 either a floated-up portion of the country rock or remnant of a 

 sill-capping which has not been resorbed. 



South of Bullawa Creek we have a great tableland capped with 

 the peaks Kaputar, Corrunbralborawah, Coryah and Ningadhun, 

 This mass consists at the base of Permo-Carboniferous sedimen- 

 tary rocks intruded by numerous sills and laccolites with a 



