286 GFXERAL COMPARISON OF 



eastward ; but under considerable variations which it 

 is necessary to explain, as the discordant positions of 

 the different Chlorite isles depend on them. 



It was shown, that in Gigha, the bearings of the 

 elevated edges were north-east, or a little more northerly. 

 The same disposition will be found to pervade the cor- 

 responding prolongations on the mainland, and by this 

 the forms of Loch Tarbet and Loch Killisport are 

 determined ; the boundaries of each of these being 

 identical with the course of the strata. This portion 

 lies near the south-eastern boundary of the series, and 

 thus Gigha and Cara are also situated on the confines 

 of the whole deposit. In proceeding to the northward, 

 the line of bearing gradually assumes a more northerly 

 tendency ; the effect of which on the forms of the 

 coast is also marked in the disposition of Loch Swin, 

 and in that of the shore from Keils point to the 

 extremity of Loch Craignish. This direction, as already 

 mentioned in treating of the Craignish isles, is north- 

 north-east, and thus these islands, as \vell as those of 

 St. Cormac, appertain to a part of the series which 

 lies at nearly equal distances from the middle and from 

 the north-western boundary. In approaching still nearer 

 to this boundary, the strata gradually assume a position 

 still more northerly, which is indicated, as before, by 

 the forms of the coast, while it is also visible in the 

 strata themselves in numerous places. In Shuna, as 

 was already shown, the direction becomes nearly north, 

 the tendency to the eastward scarcely amounting to 

 half a point; and with this, the small islands in the 

 channel leading to Loch Melfort, which it was not 

 thought necessary to describe, correspond. It was 

 also shown that in this island a sudden flexure took 

 place to the north-east by north; the only example of 

 such a change which I observed throughout the whole 

 extent of this series. That flexure is indicated on the 



