IGO Scientific Proceedings, Royal Dublin Society. 



Craig-na-slioke, due north of Money more, recorded at page 159 of 

 " Kinahan's Geology of Ireland." 



Usually under the lignite, there is a small band of carbonaceous 

 clay, containing fossil wood, and immediately under this, the 

 altered lithomarge or bauxite ; the purest bauxite being on top or 

 nearest the carbonaceous clay, in depth however, it becomes 

 more and more ferruginous, and ultimately, it changes into 

 lithomarge. Small pieces of lignite have been found in the 

 pisolitic ore seam, in the mines near Ballymena, the Mountcashel 

 mines, and rarely in the Glenarifi" mines, although on the rise of 

 the beds, both towards the north and east at Throstan and 

 Ardecliaes, the lignite is found to replace the pisolitic ore, and in 

 such places, the ferruginous pavement of the ore is replaced by 

 aluminous clay or bauxite. The lignite seems nearly invariably 

 to occur at the margins of the basins of iron measures — and if 

 these iron ores are lake deposits, the lignite is the remains of the 

 shore vegetation — and if the main measures, are one great 

 deposit, then, it would seem to be surrounded at its borders or 

 edge by lignite. The accompanying analysis of the lithomarge 

 shows it to be essentially a silicate of iron and alumina. There- 

 fore, as bauxite is a silicate of alumina, the dissolving out of the 

 iron of the bole or lithomarge, would change either of them into a 

 bauxite; hence, it is highly probable, the organic matter from 

 the decaying shore vegetation (now represented by the lignite), 

 dissolved out the iron from the bole and lithomarge. 



Intervening between the pisolitic ore (or lignite, where it 

 occurs in the ore seam), and the roof, a steatitic clay and rock 

 called respectively, " holing" and " brushing " usually occur. This 

 steatitic clay, invariably contains numerous pisolites of crystalline 

 aragonite, which are very often partly decomposed into a soft 

 unctuous mass ; it seems probable that they were amygdules 

 in cellular basalt, prior to its becoming steatitic ; these pisolites 

 of aragonite are not uncommon in the lower dolerite flows. 

 When the iron ore is hard enough for shooting, the steatitic clay 

 is picked out, " holed " (hence the local name), by the miners, 

 causing a vacancy, into which the ore is lifted by the shot, and 

 broken off from the seam. 



The steatitic rock over the clay, in places graduates into 

 steatite, and often contains large lumps of white saponite. This 

 rock is from six to eight inches thick, and would come down in 



