page 16 note * This plate forms part of the second volume of the “Qeologist.”

page 16 note † For list of synonyms, &c., see my monograph published by the Palæontographical Society, all details not absolutely required having been omitted in the present monograph.

page 17 note * It may be as well to mention that Mr. Bennie has ascertained that Lawrieston is the old name for a place a few hundred yards from the Capel Rig quarry, and now known by the denomination of Brankamhall, East Kilbride.

page 19 note * The re-occurrence of several carboniferous species in the Permian strats appears to be almost certain, although such has been doubted by several palæontologists. It is therefore probable that the following carboniferous (C), and Permian (P) shells are identical, notwithstanding that they have received distinct specific names according to the strata in which they have been discovered. Thus Terebratula sacculus, C., = Sp. sufflata, P; ? Spirifera Urii, C, = Sp. Clannyana, P; Spiriferina octoplicata, C., = Sp. cristata, P.; Carnarophoria crumena, C., = Ca. Schlotheimi, P.; Ca. globulina. P., = Ca. rhomboidea, P.; and the Lingula Crednsri,P., have been found in the carboniferous strata by Mr. Kirkby. The re-occurrence of species is a subject that has been too often supposed impossible, and treated accordingly.

page 21 note * Sp. cristata var. octoplicata is a common shell in the lower red carboniferous sandstone of Klldress; in Ireland Sp. partita of Portlock being a synonym.

Since the publication of the first pages of my paper in the December number of the “Qeologist”, Mr. Kelly has informed me that the quotation at p. 465 relative to the arrangement of the Carboniferous system in Ireland does not represent his views, and he has kindly furnished me with the following note.

“My subdivisions are, 1, Old Red Sandstone; 2, calciferous-slate; 3, limestone; 4, coal measures. The Kildress red and yellow sandstone, which is one, is not lower coal-measures; it lies” (as I have stated) “below the calciferous-slate. Again, the Old Red Sandstone is not that which predominates. Thia rock averages about one thousand feet thick in Ireland, and is not much exposed, being covered with limestone. Our calciferous slate is considerable in thickness, and in the best developed places (Clones, near Dungarvan) is half of it made up of thin bands of limestone, the other half calcareous shale. The fossils in both inseparable, so that the calciferous slate and mountain-limestone might be considered as one division, but it is perhaps more correct to separate them into two. The Carboniferous, or Hibernian limestone is fifty feet thick at Drumguin in Tyrone, it is about fifteen hundred feet thick at Black Head in Clare, and occupies above twenty thousand square miles in Ireland. This greatly predominates; the coal-measures are two thousand feet thick, or more. The Old Red sandstone, at Kildress in Tyrone, and the Old Red Sandstone of Herefordshire are two very different things. The first belongs to the Carboniferous system; the latter is a subdivision of the Silurian rooks.”

My mistake was not therefore in in the order of superposition of the different strata, which Mr. Kelly admits to be correct; but in having endeavoured to reconcile the succession of the Carboniferous strata in Scotland with that of Ireland by applying Mr. Page's general denomination of “Lower Coal-measures” to that group which embraces all the alternations of strata which lie between the Old Red Sandstone and the mountain- or Carboniferous-limestone. The term, however, would not apply to Ireland, since in the sister island no lower coal-measures underlie the mountain-limestone, as we find to be the case in Scotland, and where Mr. Kelly suggests that the limestone may be moved up a stage, with coal-measures below it. It must appear evident to all that the term Old Red Sandstone cannot be retained for a Silurian, Devonian, and Carboniferous rock, and this is the reason why I was, and still am, so averse to applying the term, or forming a subdivision by that name for those Irish red and yellow sandstones full of carboniferous fossils; for if the Calciferous- and mountain-limestone might, according to Mr. Kelly's own statement, be united into a single division on account of the similarity of their fossils, as a palæntologist, I should add that the same reasoning might equally well apply to the red sandstone of Kildress, for there also we find exactly the same fossils as those which occur in the calciferous and carboniferous-limestone. I should therefore suggest that geologists should drop the term “old,” and in their subdivisions of the Carboniferous group say, 1, Lower carboniferous red and yellow sandstone; 2, oalciferous slate; 3, carboniferous-limestone; and, 4th, coal-measures, by which means the vexed question relative to the Old Red Sandstone would not be interfered with as far as the Carboniferous system is concerned. It is also well known that Mr. Kelly is of opinion that no Devonian rocks occur in Ireland; while Sir R. Murchison believes that there exists there also a series of many thousand feet of shales and grits above the highest Upper Silurian which represents precisely in time the mass of the Devonian rooks; this, however, has nothing to do with the red and yellow sandstone of Kildress which un-doubtedly forms part of the Carboniferous system.