The time has now come for us safely to pronounce, from palæontological evidence, upon the place of those fossiliferous flagstones, with their associated sandstones and conglomerates, which are spread over a large territory in the counties of Forfar and Kincardine, and which are referred to in a paper read by Prof. Harkness before the Geological Society on the 18th January of this present year. The superficial area of country referred to in this paper is almost the same as that in the paper of Prof. Harkness, namely a district, comprehending all the lowland parts of the two counties, bounded on the north by the Grampian Mountains, impinging on the west on the County of Perth, and bounded on the south and east by the German Ocean. The objects of the papers are, however, very different. Prof. Harkness illustrated the stratigraphical arrangement of the rocks by numerous sections along the northern boundary-line, where they lean against the crystalline schists of the Grampians; our attention is now directed more to the beds as spread out and exhibited in the beautiful tract of country to the south-east of the mountains, and which have of late years begun to yield not a few characteristic and important fossils. It is now wished to state the palæontological data, collected by the writer in the course of several years, which lead to certain conclusions, in his opinion, sufficiently determining the position and the importance of these rocks in the geological scheme.