UrrER 

 Gallery. 



- v 



Wall-oases 

 6 and 7. 



228 



SCIIORLACEOUS GRANITE. 



49. — Sciiorlaceous granite, composed of felspar, quartz, 

 silverij mica, and schorl. — Penvivian Hill, near Bodmin, 

 Cornwall. 



50. — Sciiorlaceous granite, composed of schorl, dark 



flesh-coloured felspar (some in crystals), and quartz, the 

 latter somewhat rare. 



This is a variety of the schorlaceous granite of the 

 boundary portions of Penvivian Hill, which, with some of 

 the other varieties, might be employed for ornamental pur- 

 poses. They could easily be obtained in large masses. 

 Map 30. — Penvivian Hill, near Bodmin, Cornwall. 



51. — Granite, a compound of schorl, quartz, silvery mica 



/< 



It constitutes an outer portion, in a north- 



western direction, of the great Hensbarrow mass of granite 

 and exhibits the passage of the more ordinary kinds of 

 granite of the district into schorl rock, upon which repose 

 the altered schistose beds. The rock itself is situated on 

 the southern part of Fat Work Hill, and from its elevated 

 position forms an object visible from a large portion of 

 country in a western direction. 



There is a considerable mineralogical variation even in 

 the mass of Caryquoita rock itself, illustrative of the great 

 changes to which rocks of this kind are subject. Map 31. 

 Caryquoita Rock, near St. Enoder, Cornwall. 



52. 



lade's quarry. 



) 



flesh-coloured felsp 



St. Bre- 



o3. — Geanite, composed of schorl, quartz, 



felsp 



and much silvery mica. — Above St. Martin's Bay, St. 

 Martin's, Scilly Islands. 



54. 



■Porpiiyritic granite, composed of imperfect crys- 



W 



base, with a few minute spots of silvery mica. Map. 31. 

 From the skirt of the Carmarth granite, near St. Day, 

 Cornwall. 



55 and 56. — Porpiiyritic schorl-rock, composed of 



quartz and schorl. 



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