264 



colour varies from light honey-yellow to a red dish -brown 

 Two samples, obtained by the bulk concentration of the ore- 

 on a Wilfley dry table, were submitted to Mr. J. C. H. 

 Mingaye, who kindly analysed them and obtained the follow- 

 ing results : — 



Sample 1. Sample 2. 



Rare earths of the Cerium Group 



as oxides 25'04 % 66*48 % 



Thoria (ThO,) ... O20 % 016 % 



The No. 2 sample was much more free from admixture of 

 other mineral matter. Both will be noted to be unusually 

 poor in thoria. 



6. Cordierite. — iVssociated with the corundum-schist r 

 already referred to, near Mount Pitt, is cordierite-rock. On 

 account of the abundance and excellence of the material this 

 forms a notable occurrence of the mineral. The distribution 

 is irregular throughout the zone affected by pneumatrolysis, 

 but is more abundant and appears in distinct bands in the 

 peripheral belt. Usually it is admixed with corundum, silli- 

 manite, and some mica ; but in places outcrops of almost 

 pure cordierite-rock appear. Where there is much cordierite 

 the corundum is pink. Some perfect double-ended hexagonal 

 pyramids of pink corundum have been met with embedded in 

 the cordierite. In one place the rock is about half-pink 

 corundum and half cordierite, and there lumps of corundum 

 many pounds in weight were got. Normally, it is of a waxy 

 appearance and a brown colour, but is also found very light- 

 coloured and even black. Its microscopic characters are 

 normal and the pleochroic halos are beautifully shown. 



7. SHU m emit e\ — Microscope sections show this mineral 

 to occur in notable amounts in association with the ccrclierite 

 just described. It is normal in character. This is probably 

 the most important occurrence of this mineral yet recorded in 

 South Australia. 



8. Spinel. — Large octahedral crystals of the spinel, 

 pleonaste, are frequent in the corundum-mica-schist belt near 

 Mount Pitt. They are opaque, and reach an inch in 

 diameter. The octahedral form is perfect. The composition 

 of the spinel appears to vary in different portions of the 

 outcrop, but the prevailing type is best described as a 

 pleonaste. The crystals are often embedded in the soft mica 

 and can easily be isolated. 



9. Spin- in-. — Mr. Greenwood was the first to bring in 

 specimens of this mineral from the Mount Painter district. 

 These were examined chemically and identified by Mr. W. T. 

 Chapman, of the Mines Department. An examination of the- 



