. 213 



XIL—JYotes on Belowda Sill Mine. B^j Q.Jssi Neve Foster, B. A. , 

 D.Sc, F.Gr.S., Joint Son. Secretanj. 



Read May 2lst, 1875. 



BELOWDA Hill Mine, when I saw it some eighteen months 

 ago, was simply an open cast working, on a so-called lode, 

 40-ft. wide. I am of opinion that the lode is merely altered 



granite. It consists of 

 B E 



6 * a o 







a 



quartz, with a micaceous 

 mineral, and the felspar 

 has evidently been re- 

 placed by schorl and tin. 

 In some places small 

 grains of tin are seen 

 scattered through the 

 rock, in others there are 

 large grains of tin in the middle of a cavity left by the decom- 

 position of a felspar crystal. It appears to me that the granite 

 was altered by small veins, such as A A, B B, or rather by the 

 mineral solutions which they brought up. These veins, from 

 2 inches to 6 inches wide, consist either of schorl, or quartz 

 and schorl, and sometimes a little tin. In the altered granite, 

 you see cavities, C, D, E, shaped like orthoclase crystals, and 

 filled with schorl, or schorl and tin. 



I was told that the stuff yielded on an average ^about ^ per 

 cent, of tin. 



Note on a new locality for the Mineral Pistacite (Epidote). 



AT the last Spring Meeting I presented to the Museimi some 

 specimens of garnets and asinite which were found in a pit 

 close to the cross near the old church in the sand, Perranzabuloe. 

 I revisited the locality a few months ago, and was rewarded by 

 finding some pistacite. The mineral occurs in the form of small 

 prismatic crystals of an oil-green colour, some of which are J-inch 

 long. 



