Societies and Academies

Abstract

LONDON. Geological Society, February 16.—Prof. A. C. Seward, president, in the chair.—A. C. Seward: The earlier recoids of plant-life (presidential address). Reference was made to the views of Dr. Church on the origin of life in the waters of a primeval world-ocean, and on the origin of terrestrial vegetation from highly-organised Algæ transferred by emergence of portions of the earth's crust above the surface of the water. The vegetation of the land may have received additions from upraised portions of the crust at more than one epoch in the history of the earth. The course of evolution is probably more correctly illustrated by the conception of separate lines of development, than by that of a branching tree implying the common origin of the main groups of plants. The unfolding of plant-life must be considered in relation to the changing geological background. Diffusion-phenomena, as illustrated by the so-called Liesegang figures, possibly explain the origin of some of the structures which are usually attributed to organic agency. We have no knowledge of any Pre-Cambrian land-flora. The phyla of Lycopods and Ferns are regarded as independently-evolved groups. The wide geographical range of Archæopteris was emphasised, and reference was made to the difficult problems laised by the occurrerce of Upper Devonian floras well within the Arctic circle, at least equal (in the variety of the plants and in the vigorous development of the vegetation) to the more southern floras of Ireland, Belgium, and other regions.