170 Proceedings of the Royal Physical Society. 



rocks. Up the lake, a little beyond the mouth of the Awe, 

 a felspar porphyry is seen under the granite, into which it 

 appears to pass. This porphyry shows divisional planes 

 ranging N. 30° W. At the bend of the loch, about two 

 miles above Bunawe, the divisional planes of the granite are 

 vertical, with a N.E. by N. strike, directed exactly to the 

 valley between the Buachaile Etive mountains. This tract 

 is one of the most instructive in Scotland in relation to the 

 present subject. 



5. Arran.—hi ascending Goatfell from Brodick, at the 

 mill-dam, where the junction of the granite and schists 

 occurs, the latter are very hard and quartzose, commonly of 

 a greenish grey colour, but sometimes dark, and resembling 

 certain carboniferous shales. The granite sends veins into 

 the schists, some of them only two inches wide. The sub- 

 stance of these veins is fine-grained, chiefly felspathic, and 

 is firmly welded to the schists, though the line of demarca- 

 tion is most distinct. The granites of Goatfell, Glen Eosa, 

 Caistael Abhael, and of Arran generally, are chiefly composed 

 of felspar, the quartz being in considerably smaller quantity, 

 and the mica very deficient. In Glen Eis-na-bearadh, be- 

 tween two and three miles from Loch Kanza, a dyke of fine- 

 grained granite appears in the bed of the stream. Further 

 down, this dyke is seen to be connected with a mass of 

 the same character, underlying the ordinary large-grained 

 variety, and penetrating it in veins. The fine-grained 

 granite is in some places almost wholly felspathic. Near 

 the foot of the glen the junction of the granite with chloritic 

 schists is well seen, the latter dipping under the former at 

 angles of about 60°. The schists constitute the bulk of the 

 conspicuous hill called Toirnaneidnoin, on the west side of 

 which, at a great height, they are seen to be penetrated by 

 granitic veins. Near the junction the schists are very hard, 

 and shew alternating dark and light coloured laminae, gener- 

 ally even, but sometimes curiously contorted. At the junc- 

 tion of the glen with Glen Chalmadail, the schists are verti- 

 cal, with a W.N.W. to E.N.E. strike. 



6. Portsoy. — A short way east of the town (upon the 

 shore) the schistose rocks are nearly vertical, and consist 



