Great Valley of the Scottish Lowlands^ 115 



is particularly exemplified by the Clyde, the Frith of Forth, and 

 very probably by that part of the Irish Channel which is situ- 

 ated within the prolongation of the lines before adverted to, as 

 they flow through or cover strata of the coal formation, which 

 though now removed by, or concealed beneath their waters, we 

 have every reason to presume had once been continuous with 

 those that are still visible on their opposite shores. 



The connection between the Lothian coal-fields and that of 

 Fifeshire, is very apparent, both in the general direction of the 

 strata as shewn by their outcrop on the opposite shores of the 

 Frith of Forth, and in the number and thickness of the beds of 

 coal in each, which exactly correspond. Coal, too, is worked to 

 some extent under the bed of the Frith at the Wemyss colliery 

 in Fifeshire ; but, in consequence of the frequent dislocations and 

 other changes that may be attributed to the influence of igneous 

 rocks, it would be difficult to establish the complete identity of 

 each particular stratum on both sides of the water. 



The carboniferous strata seen in the Island of Arran, and at 

 Campbellton in Kintyre, appear to be only portions of the bed 

 of the Irish channel, that have either been brought up to their 

 present positions by the elevation of the plutonic rocks with 

 which they are associated, or left in those situations when the 

 disruption took place, by which that channel was formed ; for al- 

 though the coal district does not immediately shew itself on the 

 Irish coast except at Ballycastle, being cut off by the trap of 

 Antrim, there are still sufficient indications of its former existence 

 along that shore, to prove the geological connection in this, as 

 well as in most other respects between the west of Scotland and 

 the north-east of Ireland. 



The Scottish coal-measures having hitherto been very imper- 

 fectly described, their exact position in the series, as compared 

 with that of the coal formation of England, has never been pre- 

 cisely determined ; and although more than forty years have 

 elapsed since the remarkable organic remains which have lately 



p 2 



