Mr. Weaver on the Geological Relations of the South of Ireland. bS 



the floor of the coal is black shale, and the roof slate-clay or sandy slate; but 

 there are a few cases in which the floor is slate-clay or sandy slate, and the 

 roof is either black shale or gritstone. 



A third level was brought up, also from the south, into Dromenagh, about seven hundred yards 

 in length, cutting the coal at the depth of thirty yards from the surface. 



Here are four coal seams, each about one foot thick, composed of conchoidal 

 anthracite, the intervening coal measures being respectively sixty to seventy 

 yards thick, and all dipping about 60° to the south. The floor of all these 

 seams is black shale, and the roof gritstone. The beds of coal wrought in 

 Clonbannin and Kil, are said to be the western extension of those of Drome- 

 nagh. To the north of Dromenagh, approaching the Brogeen river, the grit- 

 stone dips 80° to the south. 



In the Island of Doghill the floor of the coal also is black shale, and the roof 

 gritstone, and the dip south. 



In Gurrane the coal seam is one to two feet thick, the floor being gritstone, 

 and the roof black shale two feet thick, over which lie grey sandy slate three 

 feet, gritstone two feet; then slate again, &c., all dipping 70° to the south. 



In the shale of this district may occasionally be observed small nodules, and 

 even thin discontinuous layers of clay ironstone; but the ore does not appear 

 to be at all abundantly distributed, either in this or any other portion of the 

 South Munster coal tract. 



The preceding notices may suffice to convey an idea of the general structure of this field, in 

 which no excavations have hitherto been made to a greater depth than eighty yards from the sur- 

 face. 



{QQ.) Theconsiderable quantities of iron pyrites which sometimes accompany 

 the coal, are in places impressed with plants, and the coal itself seems, in a 

 great measure, composed of a congeries of vegetables. The impressions occur 

 also both in the dark and light-coloured shales, and in the clay-ironstone. The 

 vegetable remains to be obtained from the refuse of the coal-pits, appear chiefly 

 assignable to Equiseta, Calamites, Filices, Lepidodendra, Stigmarias, and Si- 

 gillariae, besides numerous impressions of indistinct reed-like plants and grasses. 

 Compressed stems of Stigmarias ten or twelve yards in length sometimes occur 

 in the black shale, also partially flattened trunks of Calamites. Of the latter, 

 I have a fragment, measuring in the transverse section, eleven inches by eight 

 inches; but the colliers assured me, they were sometimes found as large as 

 eighteen inches by twelve inches. In the StigmariEe, Sigillariag, and Cala- 

 mites, the external coating consists of coaly matter, while the interior is fine- 

 grained gritstone. 



