116 A. J. R. Atkin — Scheelite near Barhermlle. 



which is being encroached upon by the surrounding crystals. Many 

 of the smaller lapilli show a similar structure. Others consist of 

 a mosaic of quartz grains, probably with felspathic ones intermixed ; 

 the mosaics of varying grain, some being coarser than others. 

 A little calcite is present in irregular patches. 



We have probably here to do with a fine volcanic breccia. 



Note. — My time at Klerksdorp was limited ; the neighbourhood 

 is interesting, and appears to be one around which considerable 

 volcanic activity has been focussed. 



No. 28. — An obsidian. This does not fall within the Transvaal 

 Series. It was given to me by Mr. Sydney Eyan, who collected it 

 upon the Lebombo Range, which lies in Portuguese territory, between 

 the eastern border of the Transvaal and the East African coast. 



Meg. Has the appearance of pitch. Sp. gr. 2-3. 



Mic. The rock consists of a light-brown glass ; X 250. The 

 glass is seen to be crowded with trichites disposed almost exclusively 

 in stellate forms, the delicate filaments radiating outwards from 

 a central point. These are, in turn, very frequently arranged in 

 axiolitic strings, running in parallelism along the lines of flow. 

 There are a few spherulitic groups. They give the usual cross 

 in parallel, polarised light. Some of the crosses break up into 

 distinct hyperbolas as the stage is rotated. A few rounded crystals 

 of sanidine constitute the only crystalline elements noted.^ 



IV. — An Occurbence of Scheelite, near Barkervillb, B.C. 



By Austin J. R. Atkin, Esq. 



LYING in the heart of the gold belt known as the Barkerville 

 District, Hardscrabble Creek was discovered by the pioneer 

 prospectors in 1867, and has ever since been noted for the number of 

 heavy minerals associated with the gold. Galena and various iron 

 minerals were recognized, but the most troublesome was a heavy 

 white substance, which caused great trouble to the miners by packing 

 in the sluice-boxes so tightly that the gold was carried over the 

 firmly set particles by the amount of water required to keep the 

 riffles clean. An investigation by an economic geologist of high 

 standing of some lumps of the alleged mineral showed it to be 

 barium sulphate, and no examination was made of the smaller 

 particles. 



Last Winter the author was asked to suggest some possible way 

 of getting rid of this most troublesome mineral, and went down to 

 see the workings. While there some mineral was noticed that 

 was certainly not barytes, and a careful examination — since checked 

 many times — showed the presence of scheelite of good quality. 

 Shortly after the author's examination the white mineral disappeared, 

 so he advised a careful search for the reef, or deposit, close to the 

 face being worked at that time. Very little search revealed this 



1 The thin sections were cut for me by Mr. Gregory, Mineralogist, of Kelso Place, 

 South Kensington. 



