1. Inselberge, which form striking features in the landscape of most of tropical Africa, have attracted the attention of many writers, and various theories have been advanced to explain their formation. Passarge (I) considered that desert conditions are the most favourable for their maintenance, as wind scour was believed to be a potent factor in the deepening of the hollows between them. Bornhardt (2) and Falconer (3) suggest that they may result from repeated cycles of pluvial erosion, due to normal crustal oscillations, and with this view Theile and Wilson agree (4). From a study of the inselberge in Nigeria, the writer will endeavour to show that the climate of the Sudan, with its alternate wet and dry seasons, is favourable to the production of inselberg landscape.

The system magnesia-alumina-silica is one of great importance in petrology, and the paragenesis of its constituent minerals must be a subject of study in any enquiry into the thermal metamorphism of rocks which have these three components as important constituents. Such rocks include particularly those of argillaceous type, magnesian-carbonate sediments, and bauxitic rocks.

Wegener bases his theory of the drifting continents on the assumption that there are two distinct levels to be taken into account, the surface of the masses of “sal” which form the continents and the surface of the “sima” in which they float. His justification of this fundamental assumption appears to be based on the frequency curve obtained by measuring heights positively and depths negatively from sea-level, and plotting the frequencies of such measurements as in Fig. 1. Because two maxima appear, Wegener draws the conclusion that therefore two layers must be considered as having been acted upon to produce the elevations and depressions of the earth's surface, and he implies that there would be but one maximum (Fig. 1, dotted curve) if only one layer were involved.

The section of Carboniferous Limestone exposed in the railway cutting on the South Wales relief line to the west of Badminton station is a very fine one, being inferior in the Bristol district only to those of the Avon and of Burrington. There is a continuous section from high up in D1 to the top of K2.

In 1906–12 a deep boring was made at Red Hill, Upton-on-Severn, to obtain water for the town of Upton. The boring was made by Messrs. E. Timmins & Co., Ltd., of Runcorn, for the engineers, Messrs. Willcox & Raikes, of Birmingham. The particulars as to the thickness, etc., of the Triassic rocks here are of considerable interest and I am indebted to Dr. J. Selwyn Cowley, of Upton-on-Severn, for lending me Messrs.

Speculation as to the causes of the great intrusions known as batholiths is coeval with petrology as a science. Daly says that batholiths are “the least understood of all the intrusive bodies. If they were truly understood there would be no ‘problem’ of the igneous rocks”.1 This, no doubt, puts the matter too strongly, but there is nevertheless much truth in the statement, and the “problem” is of the greatest importance in petrogenic theory.