The following investigation was undertaken not only with a general descriptive aim, but also to endeavour to ascertain how far correlation of isolated plutonic outcrops can be made by means of the study of the accessory minerals. It is in addition an attempt to supply further evidence bearing on the relative ages of the Jersey granites and diorites in view of the opinion of Dr. G. H. Plymen, based on field evidence, that the granites are of two ages, but both Pre-Cambrian, the Mont Orgueil and Gorey granite being the older.

In my paper on “The Massive Chert Formation of North Flintshire” certain views were expressed which do not accord with conclusions stated in various Memoirs of the Geological Survey. The object of this paper is to support my views by further evidence.

In a recent paper I stated that the hypothesis of a continuously cooling earth had “consistently failed to lead to any adequate explanations of fissure eruptions and other volcanic and tension phenomena, mountain-building processes and their distribution in time and space, and the alternation of marine transgressions and recessions”. It seems to be desirable that I should further justify this sweeping integration of objections, for Dr. Harold Jeffreys, who has actively explored the consequences of this theory during recent years, takes exception to my discouraging view of the position, and claims that the alleged failures include the principal successes of the theory. The evidence on which my summary indictment was based will be reviewed in this paper; and attention will be directed to certain other phenomena—such as the growth of geosynclines—of which the significance has not yet been generally realized. As a preliminary it will be convenient to discuss the gradually converging evidence bearing on the thickness and substructure of the continents.

Many travellers in Western China have remarked the presence of ancient moraines long since severed from the glaciers which made them, of glacial lakes, ice-worn valleys, perched blocks, and other relics of glaciation. Throughout the Tibetan Marches, in the provinces of Szechuan and Yunnan, such evidence is abundant. Even on the southern face of the Himalaya, where very large glaciers exist, Hooker showed that the ice once extended over a much greater area.