No. IV. APPENDIX. 375 



occasional facets of white mica. This mica schist passes 

 into a white gneiss, composed of quartz, white felspar, 

 and black mica, penetrated by veins, coarsely crystal- 

 lised, of the same minerals. Yellow and white sand- 

 stones are also found in small quantity on the islands, 

 reposing upon the granitoid rocks. 



7. Capes Oshorn and Warrender, lat. 74° 30' N., North 

 Devon. — The granitoid rocks between these two capes 

 are composed of graphic granite, consisting of quartz 

 (grey) and white felspar; this graphic granite passes 

 into a laminated gneiss, consisting of layers of black 

 mica and white translucent felspar, sparingly mixed 

 Vfiih quartz ; with the gneiss are interstratified beds 

 of garnetiferous mica slate, consisting of quartz, pale 

 greenish wliite felspar, black and white mica in minute 

 spangles, and crystals of garnet, rose-coloured, dissemi- 

 nated regularly through the mass. Quartziferous bands 

 of epidotic hornstone occur with the foregoing beds ; 

 and the whole series is overlaid by red sandstones, of 

 banded structure, which bear a striking resemblance to 

 those that overlie the granitoid beds of Wolstenholme 

 Sound. 



8. North Somerset. — The granitoid rocks are found 

 again on the west side of the island of North Somerset, 

 where they form the eastern boundary of Peel Sound. 

 Boulders of granite are found at a considerable distance 

 (100 miles) to the north-eastward of the rock in situ, as at 

 Port Leopold, Cape Eennell, &c. The general character 

 of the granitic rocks in the north and west of North 

 Somerset are thus described by Captain M'Clintock : — 



" Near Cape Eennell we passed a very remarkable 

 rounded boulder of gneiss or granite ; it was 6 yards in 

 circumference, and stood near the beach, and some 15 

 or 20 yards above it: one or two masses of rounded 

 gneiss, although very much smaller, had arrested our 

 attention at Port Leopold, as then we knew of no such 

 formation nearer than Cape Warrender, 130 miles to 



