These include the coal-fields of Castlecomer and Killenaule, with the surrounding districts occupying portions of the counties of Carlow, Queen's County, Kilkenny, and Tipperary, those of Mill-street in co. Cork, and a few latches in the counties of Kerry, Limerick, and Clare. The succession of the beds above the Carboniferous Limestone in these districts is remarkably uniform, and has been illustrated in the memoirs of Griffith, Kane, Meadows, and of the officers of the Geological Survey; so that all that remains for me to do is to describe the series in one district as a type of the whole, and refer the different beds to their representatives in England and Wales. For this purpose I shall take the section which may be made out in crossing the country from east to west through Carlow and the centre of the coal-basin of Castlecomer, referring to the accompanying section (fig. 1) in illustration of the subject.
It will be seen from this section that the Castlecomer Coal-field forms a basin, in the centre of which are the highest beds, surrounded by a zone of "Gannister Beds" (stage E) supported by flagstones, and these latter by shales and flaggy beds, which in their turn rest on the Carboniferous Limestone. This order of succession may be observed in many places on all sides of the coal-field ; and the strata may be arranged as follows in descending order, the stages (A, B, C, &c.) affixed to each division corresponding with those of the British series (see Table, pp. 615, 616):—
Descending Series of the Castlecomer and Killenaule Coal-fields[1].
| Stage G. Upper Coal-measures.—Absent (probably owing to denudation). | ||
| Freshwater or Estuarine |
Stage F. Middle Coal-measures (Jarrow series).—Sandstones, shales &c with several coal-seams from the "Jarrow Coal" upwards. | |
| Fossils.—Anthracosia (Unio), Myalina; Crustacea, Reptilia, &c. | ||
| Marine Series | Stage E. "Gannister Beds."—Grits, shales, and two or three thin seams of coal, with roofs containing marine shells. | |
| Fossils.—Phillipsia, Bellinurus regina (Baily), Goniatites, Bellerophon, Aviculopecten, and many others stated below, recently discovered (p. 621). | ||
| Stage D. Flagstone Series (representing Millstone Grit Series).—Beds of rippled micaceous flagstones and shales. | ||
| Fossils.—Chiefly tracks of marine Annelids or of Molluscs[2]. | ||
| Stage C. Shale Series (representing the Yoredale Beds).—Grey sandy shales, passing downwards into dark shales, with earthy limestones. | ||
| Fossils.—Goniatites sphæricus, Bellerophon, Euomphalus, Aviculopecten papyraceus, Posidonomya Becheri, P. membranacea, &c. | ||
| Stage B. Carboniferous Limestone.—(a) Upper Limestone (with beds of chert); Coralline; (b) Middle Limestone or "Calp" beds; Carbonaceous shales and earthy limestones; (c) Lower Limestone, compact limestone, often dolomitic. | ||
| Total thickness 1700 ft. | ||
