354 



PROFESSOR TTEDDLE ON 



EPIDOTE. 



1. From Balta Island, Shetland. Occurs in a geo which cuts the island near the 

 centre of its eastern cliff-lined shore. The epidote occurs in crystals of half an inch in 

 size, imbedded without any associate in a quartz vein which cuts gabbro. The epidote 

 is pale pea-green, the quartz somewhat granular. 



On 1*396 grammes — 



Silica, -531 



from Alumina, ..... "01 



•541 = 38-753 



Alumina, 



26-986 



Ferric Oxide, 



7-898 



Ferrous Oxide, ..... 



1-806 



Manganous Oxide, ..... 



•501 



Lime, ....... 



20-378 



Magnesia, ...... 



•786 



Potash, 



•25 



Soda, 



•21 



Water, 



2-376 



99-944 



Insoluble silica, 7*578 per cent. 



2. The above occurrence of epidote certainly in no way bears out the theory of its 

 resulting as a product of the alteration of hornblende. This, however, may have been 

 the case at the next locality which I quote. This is Nudista in Hillswick. 



It here occurs in dull, soft-looking crystals of an olive-green colour, of about an 

 inch in length. These crystals radiate through large foliated crystals of dark green 

 hornblende, cutting the foliations transversely. The specific gravity of this epidote 

 is 3*396. 



On 1*304 grammes — 



Silica, 



•484 



from Alumina, 



. -009 





•493 = 37*866 



Alumina, 



24-722 



Ferric Oxide, . 



9-961 



Ferrous Oxide, 



•361 



Manganous Oxide, . 



•536 



Lime, .... 



23-104 



Magnesia, 



•766 



Water, .... 



2-822 



100-138 





