Some years since the writer described, in a short communication read before the Society and printed in the Quarterly Journal, the breccia at Ballochmoyle and the red and purple strata found near Catrine in Ayrshire. As to the latter, he expressed no opinion whether or not they were Permian or Carboniferous, evidence being then wanted to decide that question; but his impression was that they were Carboniferous strata much higher in the series than any which had yet been described in Scotland. A visit to the locality a few days since enabled him to establish beyond doubt that the strata at Ballochmoyle Braes, Catrine, and Sorn represent a coal-field as high as any in the English series,—in fact, one similar to those at Ardwick, near Manchester; Uffington and Leebotwood, near Shrewsbury; Buxterby, near Nuneaton; and Lane-End, Potteries. Mr. Ralph Moore, in his valuable sections of the Scottish coal-fields, gives the Ayshire strata as follows: In the remarks accompanying the ‘First Sketch of a New Geological Map of Scotland’, published in 1861, Sir R. I. Murchison and Mr. Geikie say, at p. 13,— “Another chief feature of the present map, as distinguished from all other maps of the country, consists in the subdivision of the Carboniferous formation. “This group of Rocks consists in Scotland of the following members:— “The Upper Coals represent, wholly or in part, the true English Coal-measures, which lie above the Millstone-grit. They occur, in Scotland, in four basins,—one in Mid-Lothian, a second in Fife, the third and