73 



bestowed, this object might doubtless be accomplished." (Guide to 

 Arran, p. 12). The weathered surface of the granite is generally 

 white ; but the prevailing colour in a fresh fracture is red. It is 

 fine grained, with little mica in proportion to the quartz and felspar, 

 and is very similar to the fine grained variety of the interior. Drusy 

 cavities often occur, lined with crystals of quartz and felspar. Mr. 

 Ramsay states (p. 12), that "It sends forth veins into the adjacent 

 sandstone; while specimens of the sandstone, much altered by the 

 effects of intense heat, may even be found enclosed in the granite." 

 We have not noticed these cases of intrusion ; nor are the precise 

 spots mentioned, so that we might verify them. We have, however, 

 seen such in connection with the porphyry of Windmill hill, to which 

 the granite succeeds on the west, and also in connection with the 

 new granite tract to be next noticed. 



The Craig-Dhu Granite. 



51. The other granite tract lies on the south side of the Shiskin 

 road, nearly opposite the farm house of Glaister. Here the hill, whose 

 base is skirted by the road all the way down from the " String," 

 overhangs the valley of Mauchrie water in a steep cliff called Craig- 

 more, Craig-Dhu, or The Corby's Eock. This cliff is the outer 

 edge of a small plateau or table land, cut off from the higher ground 

 behind, towards Doir-nan-Each, by a deep hollow which completely 

 isolates it. The summit is 700 to 800 feet above the valley, and is 

 more than a quarter of a mile long, by one to one and a-half furlong 

 broad. It descends steeply towards Shiskin on the south-west, and 

 slopes gradually north-east towards Moniquail. The summit and 

 sides of this plateau are formed of fine grained granite, very similar 

 to that of Ploverfield. The base of the cliff towards Mauchrie water 

 is covered by a long talus of granite blocks and smaUer fragments, 

 reaching to within 200 or 300 yards of the road, and appearing even 

 at that distance of very different aspect from fallen masses of sand- 

 stone. See last cut, b, c. 



The granite here seems to rise either through the old red sand- 

 stone, or at the junction of this rock with the carboniferous strata. 

 The granite is nowhere seen in situ at a low level ; the talus before 

 mentioned obscures the rocks along the base of the hill ; and the 

 ground by the roadside, and along the valley, is deeply covered with 

 alluvium. At one spot only could we detect any rock in situ. Im- 

 mediately below the bridge, by which the road crosses a small 

 stream, the water runs over a projecting mass, which seems to be 

 either a serpentine, a greenstone with much felspar, or an iron-shot 



