Upper 

 Gallery. 



Wall-oases 

 6 and 7. 



222 



GRANITE. 



separate crystal 



s 



( 



Mar 



quartz. — Bars Oban, Argyleshire. Presented by the 



quis of Breadalbane. 



7 # Grey granite, composed of translucent quartz, crys- 



Dalkey, 



fel 



much black mica and quart. 



Ite felspar 

 Strontian, 



tals of 

 Dublin. 



8. 



(o rti 



Argyleshire. 



9. g RE y granite, a ternary compound, in nearly equal 



proportions, of orthoclase (lohite potash-felspar), black mica, 

 and quartz. — Aberdeen, Scotland. 



10. Red granite, a ternary compound of two varieties 



of felspar (ivhite and flesh 

 quantity of mica 



Presented by the Duke of Argyle. 



11. 



felsp 



(white and flesh 



Extensively used as a building material ; the steps at the 



Mu 



Peterhead, Aberdeenshire. 



12. 



(white 



es of felspar 

 In the speci- 



men the felspar constitutes the predominant ingredient, 

 while the mica is comparatively scarce. — Blackhill, Stirling- 



shire. 

 13. 



flesh-coloured ft 



and black mica. This specimen shows the general character 

 of the mass of granite which extends, north and south, from 

 Camelford to St. Neotts and St. Cleer, and east and west 

 from St. Broward and Blisland to Five Lanes and Tre- 

 bartha. (See Geological Maps, 25 & 30.) In some places 



the granite is porphyritic, containing 



large crystals of 



Or 



M 



V.: 



A 



I? 



' 1 1 



I 



iff 



$ * 



i 



00 

 



t; 



'• 



10 





ft 



.inoi 

 See 



mite 



- 



- 



,-Fi 



osey, 

 -Fi 



i T! 

 Bike 



Uv 



ir.au 



tin? 



felspar, and, occasionally, on the skirts of the mass it is |«D 



schorlaceous, containing schorl, which often appears in -F 



little radiated bundles in the granite. The highest point e D 



of this mass of granite is the rocky hill named Brown \ 

 Willy, 1,368 feet above the level of the sea, according to 



I 





t 



