696 GREAT SERPENTINE BELT OF NEW SOUTH WALES, iii., 



times shows strong fluxional arrangement [e.g., N.T., 87]. The 

 rocks are almost free from ferromagnesian minerals, or may con- 

 tain a small amount of biotite. finally, there is a rock [N.T., 404] 

 occurring on the same ridge, composed of rounded grains of 

 quartz and acid plagioclase about 1 mm. in diameter, with a very 

 little, fine-grained base. It may be considered a soda-aplite. 



(c)The sphene-granites of Moonbi have been described by Mr. 

 G. W. Card(18, p. 2 10). Summarising his remarks, the rock is 

 not conspicuously porphyritic. It contains hornblende and biotite, 

 with a tendency to segregate with magnetite into basic patches. 

 Sphene is plentiful. Felspars predominate, with orthoclase and 

 plagioclase in varying proportion, the latter zoned oligoclase. 

 Quartz is not very abundant. An analysis is given of the granite 

 from Walcha Road, a portion of the same massif (Table iii., p. 

 706). 



These granites also extend northwards from Tamworth to At- 

 tunga, and, in Horsearm Creek, many basic segregations were 

 noticed by the present writer. In these, the colourless and coloured 

 minerals are present in about equal amounts. Orthoclase and oli- 

 goclase are about equal, quartz is rather less abundant. The pre- 

 dominant, coloured constituent is biotite, which contains a little 

 zircon. Almost colourless augite is rather subordinate, and decom- 

 poses peripherally to actinolite. A little magnetite is present in 

 small cubes. 



(d),(e),(/) T ne Tingha granite (d), and the acid tin-bearing 

 granites occur near the great bend on the Gwydir River, 30 miles 

 south-east of Bingara. They have been described by Mr. Andrews 

 and Mr. Cotton. Mr. Andrews classes the Bendemeer granite with 

 the acid granite(18, p.212, 219; 19, p.742). 



The Tingha granite is porphyritic with plagioclase and quartz 

 phenocrysts, with biotite, hornblende and accessory apatite, and a 

 second generation of quartz and felspar in the base. Local modifi- 

 cations are very porphyritic, and contain pegmatites and tourma- 

 line felsite dykes. The acid granites are coarsely crystalline, con- 

 sisting of quartz and orthoclase, with sometimes a little biotite and 



