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GRANITE. 



225 



28. — Small-grained granite, composed of quartz, fel- 

 spar, mica, and schorl. Map 33. — Castle an Dinas, Corn- 

 wall. 



29. — Granite, composed of much felspar, forming sepa* 

 rate crystals ; quartz, also with a tendency to form separate 

 crystals ; a little mica, and a small quantity of schorl. 

 Map 33.— Near St. Hilary, Cornwall. (See "Keport on 

 Geology of Cornwall," p. 175.) 



30. — Granite on the side of a tin lode, and composed of 

 felspar in a decomposing state, quartz with a tendency to 

 crystallize separately, a green steatitic mineral, a small 

 quantity of silvery mica, and a little schorl. Map 31. 

 Beam Mine, Cornwall. 



31. — Granite, composed of quartz, mica, schorl, and 



felspar. 



The hill on which St. Dennis Church stands, constitutes 

 an island of granite, varying much in its mineralogical 

 structure, and forming a remarkable boss on the skirts of 

 the Hensbarrow granite. Map 30. — St. Dennis' Hill, 

 Cornwall. 



32. — Granite, composed of quartz, white felspar, form- 

 ing large separate crystals, and black mica, with a small 

 quantity of schorl. This forms the main mass of the rock, 

 the skirts of which, adjoining the slate district, is schor- 



laceous. Map 30. — Penvivian Hill, near Bodmin, Corn- 

 wall. 



33. — Granite, highly crystalline, composed of two varie- 

 ties of felspar, light-brown and reddish-brown, the latter 

 forming separate crystals, with quartz, silvery mica, and a 



Wheal Damsel, G wen- 



small quantity of schorl. Map 31. 



nap, Cornwall. 



34. — Fine-grained granite, composed of quartz, felspar, 

 and a green steatitic mineral, with a small quantity of schorl. 

 Map 31. — Bur thy Quarry, near St. Stephens, Cornwall. 

 (See "Report on Cornwall," p. 185.) 



35 — Granite (granitic porphyry), composed of crystals 

 of quartz, schorl, and mica, in a quartzo-felspathic base. 



H 



Upper 

 Galleky*. 



Wall-cases 

 6 and 7. 





_ ._. 



