In reviewing the tectonic features of a portion of Portuguese East Africa, south of the Zambezi, one of the present writers alone (2), and also in conjunction with Capt. R. C. Wilson (1), advanced the view that the surface topography had to some extent been affected by the same movements which were associated farther north with the Rift Zone period of Eastern Africa. This opinion was arrived at from the consideration of the physiography, the observation of definite faulting in places, especially in western Sheringoma on an extension of the Nyasa-Shire line, and also of volcanic occurrences elsewhere in significant positions.

In this paper no new theory is offered as to the formation of those rocks, found in so many places in the Tropics, known as laterites and lateritoids. Rather is it offered as confirmatory evidence of the hypothesis, which has been put forward by several writers (5), that in general they are formed by the evaporation of iron-bearing waters as they are brought to the surface by one or more causes, such as capillarity and hydrostatic pressure. The part that animal life may play in the deposition of the iron, as well as in the solution of it, does not appear, however, to have been noted (5).

The publication of Dr. Stamp's Introduction to Stratigraphy has confirmed certain doubts we have for some time entertained concerning the mechanism which he believes to have been responsible for the cycles of sedimentation during the Eocene Period. When reading through the proofs we made known to him our doubts, but as the theory appears in an unmodified form in the book, we feel justified in reopening discussion of the subject.

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.

The small collection of fossil plants from Burma here described was made in 1921 by Professor J. W. Gregory, in the neighbourhood of Tichara and the Mepale River, near the Siamese frontier, east of Moulmein. Tichara is a few miles north-west of Myawadi, on the frontier of Siam, and 14 miles to the north-east of Kawkareik. It is a little north of the Mepale River, which flows south-eastward into the Thaungyin, on which Myawadi stands.

A consideration of some unexplained physical features of both Devon and Cornwall does not hitherto appear to have been regarded as a line of approach towards various problems of Devono-Cornish geology still awaiting solution. Although the attempt is not yet by any means advanced, the results so far obtained appear of sufficient interest to communicate.

Many workers in the domain of the petrology of sedimentary rocks will welcome the article by Dr. Rastall in the Geological Magazine for January, 1923, and will appreciate the fact that certain notes therein help to make clear what may or may not reasonably be expected from this branch of geology. Judging from what has been said and written from time to time, I fear there is some amount of misconception as to what is being and has been achieved by the study of the rarer minerals and grain-size of sediments. As Dr. Rastall has paid me the compliment of referring to certain work with which I was concerned, in part during the war, it may be of interest and service if I indicate briefly the character of some of the work done and the utility of the petrographic methods adopted.

The fossils described below were collected by Messrs. B. K. N. Wyllie, Keir A. Campbell, and G. M. Lees, working on behalf of the Turkish Petroleum Company, who have kindly made arrangements for me to investigate their collection, which proves to be of some interest.

The alnoites form one of the rarest groups of dike rocks. Owing to their restricted distribution, they have remained comparatively little known, outside of the original alnoite of Alnö I., and a few North American occurrences, until the last few years. Recently, owing to discoveries in Canada (near Montreal), and near the Bohemian Mittelgebirge (in the Polzen valley), a great deal of interesting information regarding the alnoites has come to hand, which shows that the alnoites form a composite group of great interest; that the field relations of the alnoites indicate that absorption of limestone may have had an important effect in establishing the type of magma from which the alnoites are derived; and that absorption of limestone has undoubtedly given rise to a number of interesting rock types, which are to be regarded as branches of the main alnoitic stem. Most of these new rock types have been described by Scheumann (1), from the Polzen district. Some have been found near Montreal, and have been described by Harvie (2), Bowen (3), Howard (4), and the writer (5). The description by the writer of a plutonic rock (okaite) from near Montreal, which is clearly related to the hypabyssal alnoite group, adds interest to a general view of this group of lamprophyre dikes, and suggests ideas which may be extended to the monchiquite, fourchite, and camptonite groups of dike rocks.

For several years prior to 1914 the writer was engaged in the study of the mineral composition of loose detrital sediments with special reference to the rarer minerals and so-called heavy constituents of sands, the principal object of these investigations being an endeavour to ascertain what conclusions, if any, could be drawn as to the source and past history of the material and their bearing on stratigraphical and palæogeographical problems along the lines laid down by Dr. Thomas in his well-known researches on the New Red Sandstone of south-western England. In those days the subject was still in its infancy, and there were no standard books of reference dealing with it, such as are now abundant: it was necessary to evolve methods and to learn the characteristics of the minerals in grains by experimental investigation and by reference to the comparatively few published descriptions then available. This work was carried out chiefly on the Lower Greensand between the borders of Buckinghamshire and the Wash, but a good deal was also done on the superficial deposits of the neighbourhood of Cambridge and elsewhere, and some of the results obtained on the last-named group were published. The study of the Lower Greensand was, however, still incomplete at the end of 1914. After the war, for reasons unnecessary to detail here, it was not possible to continue the investigation of this particular formation on a more extended scale, as had been originally intended, and the results attained up to 1914 were published in the Geological Magazine.

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.

At the southern end of Thorney Island, about three miles S.S.W. of Emsworth, in West Sussex, there are low cliffs of London Clay covered by Pleistocene deposits. The London Clay has been folded near the top, and its surface presents a series of basin-like depressions, 3 to 10 feet in diameter, and evidently caused by downward pressure. These basins are occupied by Pleistocene gravel, which contains numerous erratics—many of igneous rocks—and resembles the better-known Erratic Gravel of Selsey. The Erratic Gravel is covered by Coombe Rock and Brickearth, which form the top of the cliff, as shown in the diagram.

1. Submarine erosion off Holderness is a fact, as pointed out by Winn.

2. The rate is greatest between H. and L.W.M.'s.

3. Between L.W. and 20 feet it is much less rapid.

4. Below 20 feet it still further diminishes to the 30-ft. line; outside which it apparently dies away.

5. Groynes—taking the long view—are unfortunately only a temporary safeguard for this district of easily eroded clay.

The writer's sincere thanks are due to Mr. G. W. Lamplugh, F.R.S., for his very kind and keen interest in the work.

Half a mile above Bredwardine Bridge on the Wye, 11½ miles above Hereford, the river on the right bank runs at the foot of an exposure of drift about 50 feet high, showing the following section: Clayey red sand with sandstone pebbles, subangular; lower 10 feet, more clayey with limestone and claystone pebbles, striated.