634 Scientific Proceedings, Royal Dublin Society. 



And again in 1867 1 he says : — 



" The Antrim [i.e. Ballycastle] coal district appears to be a prolongation of the coal 

 field of the Forth and Clyde valley in Scotland. They are in the same strike and position 

 with regard to the older adjacent rocks ; and as no one can doubt that the whole of the 

 Carboniferous formation of the British Islands was deposited at the same period, it is 

 likely that at Antrim and Glasgow, two places not very far distant, there would be a 

 typical likeness in the rocks which compose them both, as to lithological character and 

 succession. The valley of the Forth and Clyde, which is in the Carboniferous rocks, may 

 be prolonged on the map of Great Britain and Ireland. It passes through Ballycastle, 

 across Lough Neagh, by Dungannon, Caledon, and Clogher to the Connaught coal district 

 about Lough Allen. This shows that the limestone at Ballycastle. as well as the coal 

 rocks there, forms a part of the great band stretching between the Firth of Forth and the 

 Connaught coal district." 



These passages show that Kelly thoroughly appreciated the bearing of 

 the extension of the trough-valley into Ireland on the question of the possi- 

 bility of the occurrence of coal beneath the basalts. What is more, he 

 appears to have realized that the basin of Lough Neagh was a likely point 

 within this valley for the preservation of Coal Measures. Curiously enough, 

 however, he failed to perceive that the Antrim [Ballycastle] coalfield lies 

 outside the trough-valley, and belongs to a more or less distinct Carboniferous 

 basin. 



The 25-mile-to-the-inch map of the British Isles, published by the 

 Geological Survey, shows the course of the rift-valley very clearly, from the 

 North Sea to the Clyde, and from Dungannon south-west into the centre of 

 Ireland. The boundaries of this trough, where seen, are lines of such 

 remarkable straightness that it is easy to predict their course in the areas 

 where they are concealed beneath the sea, or buried beneath newer rocks. 

 Thus the northern boundary, where the Old Bed Sandstone of the trough 

 abuts against the Highland schists, follows a line of remarkable straightness 

 from Stonehaven to the coast of Arran. Here it is locally deflected by the 

 Tertiary granite intrusion of Arran, but it can be picked up again in Kiutyre, 

 where it takes a somewhat more southerly course, and at Cushendall, where 

 it tends to resume its normal south-westerly direction before disappearing 

 beneath the basalt plateau of Antrim. It emerges again at Draperstown, in 

 Go. Londonderry, and is well defined throughout Co. Tyrone. Its further 

 course towards the extreme west of Ireland is probably indicated by the 

 southern flank of the gneissose range of the Ox Mountains. 



The southern boundary, where the Carboniferous and Old Bed Sandstone 



1 John Kelly: On the Geology of the County of Antrim, with parts of the adjacent 

 Counties. Proc. Royal Irish Academy, vol. x, p. 234, 1868. 



