The second edition, which appeared three years after the first, showed that the author had been led to modify his views in several important respects. The great post-glacial submergence he now considered unproved, following in this the conclusions arrived at by Dr Jamieson of Ellon in his studies of the Scottish glacial deposits. He recognised also that the shelly boulder-clay of many parts of Scotland, such as Caithness, Orkney, Shetland, Dumbartonshire, and Ayrshire, was best explained on the lines suggested by Dr James Croll as the deposit of an ice-sheet that had invaded the land after travelling for a time over the sea bottom. In this we see the influence of Dr Peach and Dr Horne’s work on the glaciation of Caithness, Shetland and Orkney, and of Geikie’s own investigation of the glacial phenomena of the Outer Hebrides. These changes of opinion were undoubtedly well considered, and have been supported by subsequent discoveries. He also took up a much bolder attitude on the question of interglacial deposits and the relation of man to the Ice Age. While still relying to the full on the evidence cited from Scotland in the first edition of _The Great Ice Age_ in favour of the existence of more than one interglacial period, he adduced the results of Skertchly’s work at Brandon as proving that the palæolithic deposits of south-eastern England are in places overlain by genuine boulder-clay. More prominence was also given to the continental evidence for interglacial periods, especially to that obtained in the Dürnten lignite of the north side of the Alps, and of the so-called Pliocene beds of Lombardy, which even in the first edition he had confidently claimed as being really interglacial. The next important work from Prof. Geikie’s pen was _Prehistoric Europe_, published in 1881. He continued to keep abreast of the rapidly increasing literature of his subject, and although the main lines of his treatment of it required little modification, he was continually adding to his store of facts. _Prehistoric Europe_ did not receive the same welcome as _The Great Ice Age_, and this could hardly be expected. Geologists were by this time familiar with the author’s main conclusions, and the book in some measure takes us over familiar ground. But to the general reader it remains one of the most enjoyable of the author’s contributions to the literature of science.