142 PROCEEDINGS OF SOCIETIES. 



but he appears never to have reflected that the Lower Limestone, which 

 supports his supposed millstone grit to the south of Lisnaskea, in the 

 county of Fermanagh, also supports similar strata to the west of Lough 

 Erne, which, as already mentioned, are succeeded by the Upper Lime- 

 stone and the Millstone Grit of Slieve Rushen mountain, — the breadth of 

 the subjacent Lower Limestone between the calp of Lisnaskea and that 

 at the base of Slieve Rushen being but three miles, as may be seen by 

 reference to the " Geological Map." But I feel certain that no geologist, 

 who has examined the country, will agree with Mr. John Kelly in regard 

 to the geological position of the Slievebeagh mountains, but will decide 

 with me that it is rightly referred to the Calp series. 



I shall now exhibit a section extending, in a south-eastern direction, 

 from the Silurian strata at Lisbellaw, in the county of Fermanagh, across 

 the Lower Limestone valley of Clogher, thence over the Slievebeagh moun- 

 tains, which, in continuation, crossing the Lower Limestone valley of 

 Monaghan, terminates in the Silurian strata of Scot's-house, west of the 

 town of Monaghan. 



This section, in fact, forms the continuation of the section already 

 described at the meeting of the British Association held at Cork in the 

 year 1842 ; and I shall quote from the abstract of my paper which refers 

 to the Slievebeagh section : — 



" At Lisbellaw the Silurian rocks are succeeded unconformably by 

 strata belonging to the Yellow Sandstone series, which is here very im- 

 perfectly developed, owing probably to its being cut through by the 

 projection through it of the Silurian series. The Yellow Sandstone is 

 followed by the Carboniferous Slate, and this again by the Lower Lime- 

 stone, and, in continuation, by the calp and calp sandstone of the Slieve- 

 beagh mountains, from beneath which, in an eastern direction, we find 

 the Lower Limestone and Carboniferous Slate appearing at the surface in 

 the valley of Monaghan, and terminating unconformably on the gray- 

 wacke slate, which bounds that valley to the south-east." 



I shall not enter into any description in regard to the several other 

 Calp districts laid down in my " Geological Map," as I know that the 

 greater number of them have been examined by several distinguished 

 geologists belonging to our Society ; and I shall leave it in their hands 

 to decide between Mr. Kelly and myself. But as I am not aware that 

 any of them have as yet had an opportunity of examining in any detail 

 the Carboniferous System of the counties of Donegal, Cavan, Fermanagh, 

 Leitrim, Sligo, and Roscommon, I thought it desirable to make this 

 short communication in reference to that district. 



I shall only further remark, in regard to the Carboniferous System of 

 the south of Ireland, where the Calp is frequently wanting, that it is well 

 developed in the county of Limerick, along the eastern boundary of the 

 great Millstone Grit district of Munster, and I have prepared a section of 

 the series, extending from the Old lied Sandstone of Pallaskenry, on the 

 south side of the river Shannon, in a western direction, to the anthracite 

 beds south of Loughill, in which the entire suite of rocks into which I 

 have subdivided the Carboniferous System are clearly exhibited, namely, 



