Further evidence of the very dry climate of this phase is the frequent occurrence of trees apparently _in situ_ beneath the surface of fresh-water lakes, both in Ireland and Scandinavia. I was able to examine one very good example near Lough Toome in north-west Ireland. An unusually dry spring had lowered the surface of the water and a large number of tree-stools were exposed; when these trees were growing the water-surface must have been at least two feet below the level of the present outlet. Most of the lakes in which these stools are found are shallow upland basins with a small drainage area, and if the present climate became drier they would more or less completely disappear. Mr. Fairgrieve has noted the action of blown sand on the westward side of broken-off tree-stumps in a submerged forest on the shore in south Wales, which, though not conclusive, suggests dry conditions. Mr. Fairgrieve also noted the direction of fall of twenty-one trees, and found that in the great majority of cases they were blown down by westerly winds. The forest phase was short; according to the late C. Reid the land again began to subside shortly after 3000 B.C., and by 1600 B.C., in Britain at least, had reached its present level; this carries us to the beginning of the Bronze Age. In connexion with Ellsworth Huntington’s theory that the dampness of Ireland lowers the energy of its inhabitants, it is interesting to note that this dry period apparently corresponds to the legendary Heroic Age, when the vigour of the Irish reached a level never since attained. Civilization in Scandinavia also seems to have benefited by the drier conditions, for Scandinavian technique advanced rapidly to a high level about 1800 B.C. But though there is evidence of a considerable sea-borne commerce with Britain and Ireland, there appears to have been comparatively little land traffic between different parts of Scandinavia at this time. In fact, to primitive man dense forest with thick undergrowth was almost impenetrable. But at the close of the forest phase and the beginning of the peat-bog phase the trees were weakening under conditions becoming unfavourable. Such dying forests are marked by the absence of undergrowth and young trees, and afford safe and easy land communication. Accordingly we find that by 1500 B.C. a considerable traffic had developed across Scandinavia by land.