48 



referred to as encircling the island, it appears that when the sea 

 stood at that ancient level, Bute consisted of four islands separated 

 by narrow channels. 



The various strata exhibited in Bute, are the terminal portions 

 of those great bands of rock, sedimentary and igneous, which 

 extend across the country from sea to sea, as already noticed. Mica 

 slate occupies the northern portion between the Kyles on the north, 

 and Kames and Ettrick bays on the south. The rock has its usual 

 character and aspect ; and rises into hills of nearly 1,000 feet eleva- 

 tion. The district south of this, bounded by the Eothesay valley, 

 consists of the two upper slates, the common clay and chloritic. 

 Subordinate to these are great beds of quartz rock, the most con- 

 siderable of which forms the high ridge called Barone hill, with a 

 picturesque old ruin overlooking Rothesay on the west ; and also in 

 the vicinity of Kames bay, copper veins very recently discovered 

 and of considerable promise, arrangements for working which are 

 now in progress. The portion extending from Eothesay valley to 

 Kilchattan is occupied by red sandstone ; and finally the southern 

 portion with a sub-stratum of red sandstone, consists mainly of 

 various rocks of the trap family, erupted through and overlying the 

 sandstone. The accompanying outline of the island shows the 

 relation of these strata to the valleys or depressions, which are 

 obviously a part of that system of parallel fractures ranging N.E. 

 and S.W. on both sides of the Grampians, and probably due to the 

 upheaval of this chain, and the later igneous eruptions already 

 noted. 



(a) Kames bay ; (6) RotJiesay ; (c) Kilchattan ; (m) mica slate ; (n) clay and chlorite 

 slates; (s) red sandstone ; (f)trap; (r) the terrace. 



A description of these rocks would be useless, as it would 

 merely be a repetition of facts contained in all elementary works. 

 The great body of sandstone obviously belongs to the old red 

 system ; and as well from its position in immediate sequence to the 

 old strata, as from its general mineral character seems to form 

 the lower portion of that system; but hitherto no fossils have 

 been detected in it. Like the corresponding strata on the mainland, 

 at the base of Benlomond, Innerkip and Inellan, it contains sub- 

 ordinate beds of cornstone. These are seen in several places along 

 the shore south of Bogany point ; but the beds are thin, and 

 generally contain much siliceous matter, so that the limestone is of 



