3° 



western boundary a clean escarpment of all the district rocks, from 

 the Trap to the underlying schists of Deny, along the eastern 

 boundary of the valley of the Roe, near Dungiven, and on its 

 eastern boundary near Cushendall, a similar section, and no indi- 

 cation of coal can be found there. The coal fields of Ballycastle 

 and Dungannon were really very limited, and seem to be cut off 

 from the aiea just referred to under the Trap and New Red Sand- 

 stone. Some persons may suppose that the beds of Ballycastle 

 may be continued under the Antrim rocks to Dungannon, but 

 there is no proper ground for such a supposition ; on the contrary, 

 it is clear they have no connexion. The Ballycastle coal field is 

 clearly cut off from the other parts of the county by the schists and 

 other primary rocks that surround the basin. The coal field of 

 Dungannon is of a different age to that of Ballycastle. The latter 

 belongs to a much lower zone than the former, indeed, although 

 we have in Ireland one of the largest developments of the Car- 

 boniferous system found anywhere ; that system is chiefly repre- 

 sented by its lower divisions — the Carboniferous Slates and 

 Mountain Limestone ; and the coal fields of the south occur in 

 basins on the limestone ; but mainly, the Coal Measures, if they 

 were ever deposited extensively, have been removed by denudation, 

 and now we have extensive areas of Carboniferous Limestone with- 

 out the Coal Measures that once reposed upon it. We have, in 

 fact, over the greater part of Ireland an enormous development of 

 the Carboniferous system, but it represents only the zone that is 

 below the coal. This is an answer to the often-repeated question, 

 How is it we have no coal in Ireland ? But in the north, at 

 Ballycastle, the thick-bedded southern limestone is represented by 

 shale, sandstone, and coal, like the lower Coal Measures of Scot- 

 land, which belong to a zone below the Carboniferous Limestone, 

 it being found both in Scotland, England, and Ireland, that the 

 limestone thins out almost to nothing towards the north, although 

 it is several thousand feet thick in the south, and although the 

 true Coal Measures occur over the Mountain Limestone towards 

 the south of Britain and in other countries, yet in Scotland, and at 

 Ballycastle in Ireland, the coal occurs below what may be con- 



