136 PROCEEDINGS OF THE 



Antrim coalfield into three groups, which, in a descending series, 

 consist of — 



1st, Coalbeds and blackband ironstone alternating with other 

 strata; 



2d, Limestone and impure earthy shales, with shells, crinoids, 

 and corals ; 



3d, Beds of reddish sandstone, conglomerates, and shales. 



The first group corresponds closely to the Possil and Govan 

 coal and blackband ironstone series; the second to the lower 

 limestone series of the AVest of Scotland; and the third to the 

 sandstones, conglomerates, and shales that underlie our limestones, 

 some of which are of a reddish colour, as in Arran and in various 

 tracts along the south-western base of the Ayrshire coalfield. 



Mr Hull states that he is not sure if the millstone grit series is 

 represented in the Ballycastle coalfield, and I think there is also 

 evidence from the three divisions of the strata which he gives us, 

 that the upper limestone series of the West of Scotland is not 

 there found. With us this upper limestone series consists of 

 three or four beds alternating with other strata of sandstone and 

 shale, which lie over the Possil coal and ironstone series — the 

 supposed representatives of the upper strata of the Ballycastle 

 coalfield. But as many tracts of the Irish coalfield have suffered 

 extensive denudation, it may probably be concluded that these 

 upper beds have been all swept away. 



One other point of similarity which Mr Hull notices in connec- 

 tion with the coalfield of the West of Scotland and that of Bally- 

 castle, is the occurrence of a brachiopod shell — Lingula squa- 

 miformis. In the coalfields of Lanarkshire, Eenfrewshire, and 

 Ayrshire, this shell occurs in such abundance in certain strata on 

 the horizon of the Possil and Govan ironstone series, that it 

 strongly characterises this division of our beds. Years ago Dr 

 Rankin of Carluke, in his section of the strata of that district, 

 named certain beds on this horizon as " Lingula ironstone," 

 " Lingula limestone and shale," from the abundance of this one 

 shell in the beds. This shell, though ranging Trom the lower to 

 the upper limestone series in the West of Scotland, is nowhere 

 else met with in such numbers. 



It is worthy of being noted that Mr Hull in this paper does 

 not claim to be the first to recognise the difference that exists in 

 the beds of the Ballycastle coalfield from those composing the 



