136 GEOLOGY OF ARRAN. 



mantling stratification around the nucleus which is usually 

 seen in granite tracts. The entrance of Glen Catacol 

 exhibits some fine terraces. On the south side there are two ; 

 one about forty feet in height, with which a mound rather 

 than a terrace on the other side corresponds; and a lower ter- 

 race about twenty to thirty feet high, which reaches down 

 to near the sea. "With this a terrace on the north side 

 corresponds, beginning near the farin-house, and sweeping 

 round eastward. The front of the higher terrace is cut into 

 promontories and bays, indicating the action of water upon 

 it after its deposition ; all the terraces consist of alluvial 

 matter, not of rock. When the sea stood at its former level, 

 so often alluded to already, the plain in the centre of the 

 glen must have been entirely under water there is but a 

 thin soil over rolled gravel through all its central part. On 

 the north-east part of the glen, and out eastwards over the 

 mountains towards Torneadaneoin, some very interesting 

 junctions are to be seen ; but we must pursue our way now 

 towards Dougrie. 



It is only on this extreme north-western border of the 

 slate tract that the micaceous character which prevails in 

 Cantire is assumed by the slate. Near the Free Church, 

 which stands on a lovely picturesque spot in North Thunder- 

 gay, a fine mica slate, banded with quartz, occurs ; east of 

 this there is much chlorite slate, and one mile west of it, 

 near the secluded cemetery, blue argillaceous slate, mixed 

 with the chloritic variety. But generally there is on this 

 side a greater tendency to the micaceous character. On the 

 Imochar shore, and towards Dougrie, the ordinary character 

 has become again established. The slate ceases, and the old 

 red sandstone begins to form the front of the cliff a little to 

 the west of the mouth of the lorsa ; but the junction is not 

 seen. The stratification appears to be conformable. There 

 are comparatively few dikes on this coast A little east of 

 the Free Church there are two, each of which appears to 

 bifurcate. On the Pcnrioch shore a great bed of greenstone, 



