HORN RXPEDITIOX — ECONOMIC fiKOLOGY. 



81 



were obtuiued by washing the " dirt " in the bed of tlie above-iiientioned creeks 

 until the material is reduced sutlicieutly to permit the rounded water-worn garnets 

 to be picked out by hand. Althougli the gai'nets are exceedingly plentiful, yet 

 good unfractured and clear stones are comparatively rare. The tine surface sand 

 of the beds of the creeks was often observed to have a beautiful claret-red tinge, 

 due to the intermixture of innumerable small fragments of garnet with the sand. 

 The source of the garnets was found to be a garnetiferous gneiss very lich in this 

 mineral, a typical specinien of which was gathered from an outcrop on the banks 

 of the Maude Creek. 



An analysis of some specimens of these garnets has been made by Prof. E. H. 

 Rennie, with the followinir result* : — 



Silica (SiO.,) 

 Alumina (Alp,) - 

 I'Vi-rous oxide (FeO) 

 Lime (CaO) 

 Magnesia (MgO) - 

 Oxide of manganese (MnO) 



38 "48 per cent. 



27-00 



20-28 



1-99 



■1-20 

 •35 



98-39 



" All the iron has been reckoned as protoxide, while some at least of it exists 

 as peroxide." 



* On soiiio so-callfd .South Aiistraliaii Kiilik-s, hy Prof. E. H. UtMinit*, D.Sc., Trans, and Prn(.\ ami Rejiort of 

 the Roy. Soe. Soiitli .\iistrilia, vol. \i. (for l>iS7-S). 



