76 



of most of these beds give much additional probability to this suppo- 

 sition. 



This original continuity of the beds occupying the carboniferous 

 district, appears to have been subsequently interrupted by the intru- 

 sion of the igneous rocks and hills so universally prevalent in that 

 formation, by which they have been separated into the fields or basins 

 where they are now found. The effects of Plutonic action, by which 

 these hills were produced, seem to have been the chief agents em- 

 ployed in modifying the external surface of this important district, 

 and occasioning those chemical changes and combinations in the in- 

 terior of the earth, by which, when elevated above the waters, it was 

 destined to become a more suitable habitation for the human race. 



The Pentland, Campsie, and Ochil hills, as well as many others 

 of a similar description within the limits specified, afford striking 

 examples of the effects produced by their intrusion among the coal 

 strata, at periods subsequent to the consolidation of the latter, of 

 which some instances were noticed by the author. In fact, the 

 whole country occupied by the Scottish coal-measures, displays more 

 or less the influence of such igneous hills, or of the dykes connected 

 with them. A certain degree of parallelism may be traced between 

 the principal ranges, their general bearing being from the eastward 

 of north to the westward of south, which corresponds with the gene- 

 ral strike of the fossiliferous strata; but they often appear to have 

 been protruded through the surface without any order or regularity, 

 and the dykes are found to proceed in every direction from the prin- 

 cipal masses. 



The author farther remarked, that rivers, estuaries, or portions 

 of the sea, now flow through or cover strata of this coal formation, 

 which, from the appearances on their opposite shores, were in all pro- 

 bability, once continuous. The connection between the Lothian coal- 

 fields and that of Fifeshire is very apparent, both in the general di- 

 rection of the strata, as seen 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. The appearance of the 

 carboniferous series in Arran, and at Campbelton in Kintyre, as well 

 as the indications of its existence at Ballycastle, and other places on 

 the Irish coast, within the prolongation of the lines before adverted 

 to, seems fully to establish the geological connection in this, as well 

 as in most other respects, between the west of Scotland and the north- 

 east of Ireland. 



In regard to the age of the Scottish coal-measures as compared 



