My attention was called to the subject of this paper in May 1862, during a short stay at Elie on the coast of Fife. Close to the friend's house with whom I lived a part of the sea-bank had been laid open by the waves, and among other deposits I found a bed of clay containing fossil shells, such as now live only in the Polar seas. An account of this I had the honour of laying before the Society on the 2d of March 1863. During the following autumn, while residing at Bridge of Earn, I found a similar deposit, with the same species of shells, at Errol on the Tay, and a notice of this I also laid before the Society on the 2d of May 1864, intimating that at some future period I should again ask their attention to the facts thus ascertained and the inferences to be drawn from them. The delay that has taken place has arisen from other occupations, which leave little time for such pursuits, but it has not been wholly without advantage. The cuttings of the East of Fife Railway were carried past the outskirts of Elie, and I had an opportunity of examining the series of beds, while laid open for the time, in a very remarkable way. This last autumn also, while residing on the spot for a few days, I examined with some care a transverse section, nearly at right angles to the two former; and now, in this paper, I shall endeavour first to state in detail the facts connected with these separate localities, and then to bring into one view the general results.