On tice Tertiary Iron Ore Measures. 159 



usually I'eplace the pisolitic ore seam, though in places the lignite 

 overlaps the iron ore, in which case the lignite is always separated 

 from the ore by a band of ba,uxite or aluminous clay. A good 

 lignite bed is, however, seldom found in immediate connexion 

 with the pisolitic ore seam, though it sometimes is separated by 

 a dyke only. 



To Mr. P. Gormon, who has bored through most of the lignite 

 and ore deposits of the county Antrim, I am indebted for the 

 followino; information. In all cases that have come under his 

 observation the lignite aluminous clay and ore deposits are found 

 adjoining each other; often they are separated by dykes, but 

 when these are absent, the clay and lignite usually overlap the 

 iron ore at the junction of the deposits. 



At Killymurish, where there was an extensive deposit of lignite, 

 he bored through forty feet of clay under the lignite seam, and on 

 putting down another bore a little to the south of this, on the 

 confines of the Duneny iron ore field, he cut through eighteen 

 inches of pisolitic ore so close to the dyke of separation that the 

 pavement of the ore was wanting. In another portion of this 

 clay field he boi-ed through five feet of aluminous clay, lignite 

 being absent, then three feet of brown clay, containing iron, and 

 underneath struck the iron ore deposit. At Craighill he also 

 found the ore and aluminous clay sepai'ated by a dyke. The 

 silica in this clay was in excess, and the lignite absent, except a 

 thin seam at the north-east corner. 



A.ccording to this authority, at Ballintoy, Ximenagh, and 

 Drumnagaster, the clay and pisolitic ore are found under the 

 same roof and conditions ; and he thus states : — 



" I would here mention that I have usually found the clay and iron 

 ore associated in the same liill or range of hills, and tlie clay is m variably 

 found to occupy the W. or N.W. portion of the gi-ound. T might also 

 state^ a bore hole was piit down iu. the Killymurish Lignite Mines, 

 about eighteen years ago, by a Scotchman called Twist ; his journal 

 recorded that after getting through the clay and lithomarge, he passed 

 through nine inches of coal, then nine feet of limestone, then some shale, 

 and afterwards eight feet of limestone. It was a prevalent theory at 

 that time, that the lignite was a true coal, and by boring deeper various 

 seams of true coal might be reached." 



This section is very remarkable and unlike anything that has 

 come under my notice ; possibly it was in one of the deposits of 

 the iron measures close above the older rocks, such as that at 



