AT the Linnean Society on Mar. 5, Mr. H. E. Forrest opened a discussion on “The Relation of the Fauna and Flora of the British Isles to those of North America”. Mr. Forrest first summarised the geological evidence on which his hypothesis is based. There were two phases of the Great Ice Age: (1) Ice-sheet period; (2) glacier period. During the first phase the ice came from north-west across the Irish Sea; during the second phase it came from the northeast.