During the course of a reconnaissance mineral survey of Western Togoland in 1918–19 many streams were panned, and the concentrates were afterwards examined to ascertain to what extent the heavy minerals in them could be used as a guide in geological mapping.

A boring that was completed in 1921 by Messrs. Pease and Partners, at Roddymoor Colliery, near Crook, Co. Durham, about 5 miles north-west of Bishop Auckland, is of considerable importance. I had the good fortune to be consulted in connexion with the correlation of the strata in the lower part of the section, and was also allowed to make a thorough examination of the whole of the cores. The stratigraphical results are of much interest, and it is mainly with these I propose to deal in this paper. Mr. R. G. Carruthers, of H.M. Geological Survey, also examined the cores, and on his suggestion they were broken up and the fossils in them collected by Mr. Tate, of the Survey. It is hoped that when these are determined, results may be obtained which will aid the zonal classification and correlation of the Lower Carboniferous rocks of the two north-eastern counties.

Rhombic pyroxene as a constituent of thermally altered sediments has hitherto been recorded only from a few contact zones, and, as the conditions under which it is generated in metamorphosed sediments are of some interest, these may be examined.

In 1902 the author proposed a new classification of the genus Lichas, introducing several new subgeneric names. Gürich's valuable paper dealing with the same subject, which was published late in 1901, unfortunately only came into his hands after his article was in the press, so that full justice could not be done to it. Since that time a considerable amount of work has been done on the genus Lichas, but the principles governing the classification put forward in 1902 have not been upset, and no fundamental modifications have been introduced, though many new species have been described and several new subgeneric or generic divisions have been established.

The Midland Valley region of Scotland contains the world's largest known development of igneous rocks carrying primary analcite. These rocks have been described in several publications during the last fifteen years, and some new rock-types have been defined.

The view from the old Moulmein Pagoda, looking either westward to the sea or eastward over the plains beside the Salween, is of exceptional geological attractiveness. At the foot of the hill the Salween River passes through a breach in the Coast Range to the Gulf of Martaban. To the east picturesque monoliths, tors, and sierras rise abruptly from a vast alluvial plain which lies between the Coast Range and the distant Dawna Mountains on the Burmese side of the Siamese frontier. The interest of the view in September, 1921, was enhanced by uncertainty as to the age of the rocks. The foundation of the Coast Range consists of a blue gneiss, which is worked in large quarries to provide road metal for Rangoon. The Dawna Range, on the eastern side of the basin, is also of coarse gneiss and schist. These Eozoic rocks of both the Coast and Dawna Ranges belong to the Martaban Group of Theobald, who described them as “true crystalline rocks undistinguishable in character from the ordinary gneissose rocks of Bengal”. The sedimentary rocks overlying the Martaban Group belong to the Moulmein Group of T. Oldham, and have been regarded as Carboniferous on the strength of his preliminary determination in 1856 of some fossils from a limestone hill known as the “Duke of York's Nose”, near Moulmein.

The rock fragments described herein were obtained during a cruise of investigation into the fishery possibilities of the Lousy Bank. This Bank, as defined by the 200 fathom line, is some 34 miles long, by 18 miles broad, and lies in a direction E.N.E.–W.S.W. (mag.), being situated between Faroe Bank and Rockall, and having its shallowest portion centred around the position, Lat. 60° 25′ N., Long. 12° 37′ W.

In an earlier paper (8)an olivine-basalt was described from this locality; the present contribution may be looked upon as a continuation of the study then begun. This basalt is best exposed at the southern end of the ridge in a small quarry, but several exposures are to be seen farther north. All these, where the compact, fresh-looking basalt is to be observed, are situated along or near the eastern margin of the ridge, a fact particularly well shown near the northern end. On the western side of this strip are several exposures of fine-grained, brownish rock, so well jointed that it is almost impossible to get a good specimen; an additional feature of importance is that the exposed surfaces are frequently striated. That these striations are not of glacial origin is demonstrated by their occurrence on newly-quarried surfaces, and also by the fact that specimens bounded on two sides by these striated surfaces may be collected.

Although spilite as a rock name has been in use for nearly a hundred years, there are few rocks, probably none of equal importance, so incompletely understood. Introduced in 1827 by Brongniart, “spilite” was first used officially in this country by Flett when describing the pillow-lavas of South Devon (Plymouth and Liskeard Memoir, 1907), and has now completely replaced the indefinite terms “greenstone” and “epidiorite”, by which these lavas were formerly known. It is only quite recently that the importance of spilite has been properly appreciated. The progress of research has shown that at several different geological periods lavas of spilitic type have been almost completely dominant in Britain. Typical spilites and keratophyres were extruded in Pre-Cambrian times over a very extensive area, remnants of the flows being preserved in Argyllshire (Tayvallich and Loch Awe), and in Anglesey, localities which must have been far removed from one another at that time. Throughout Ordovician times the basic lavas were almost without exception spilites or closely allied types. The best known examples of spilites in Britain are those occurring abundantly in the Devonian and lower part of the Carboniferous rocks of South-West England, so ably described by Dewey and Flett, to whom most of our knowledge of these rocks is due. To deny the important rôle of spilite in the history of igneous activity in this country is no mere difference of opinion, but a denial of fact. Yet there are many who, with the American geologists, deny not only the importance, but; even the existences of the rock. The other extreme of opinion is found in those who see in the spilitic rocks a series whose petrogenesis presents problems of more than usual interest and which they have elevated to occupy a position comparable in importance with the better known calcic and alkalic suites.

In this paper I propose to deal with the question set forth in the title in connexion with the recent works of different authors. Owing to the difficulties of international communication, I was unable until quite recently (1922) to consult the general works on the Rugosa corals published by Faurot, Jaekel, and Robinson.

The Geological Department of the British Museum is much indebted to Dr. Cowper Reed for his careful description of the Girvan fossils which he assigns to Cornulites (Geol. Mag., Vol. LX, 1923, pp. 268–76). A slight correction, unfortunately, is necessary. Various specimens received from Mrs. Robert Gray as “Tentaculites” were registered in the Department under the numbers correctly quoted by Dr. Reed. He himself, in returning the specimens to us, pointed out, also correctly, that some of them were of quite different nature. He omitted, however, in some instances, to remove those numbers from the lists that he quoted. To prevent further confusion, the numbers to be cancelled are given below. At the same time, opportunity is taken to quote the number of the specimen that is hereby selected as the holotype of each new species. The numbers then remaining will denote the paratypes.

Perusal of Dr. du Toit's masterly and illuminating paper on Carboniferous Glaciation in South Africa suggested that some notes on the early and gradual development of data relating to glaciation in South Africa, Australia, and Tasmania by the writer might not be out of place.

A recent investigation of the igneous rocks of Sark revealed the presence of an interesting series of basic intrusions particularly well exposed near the northern extremity of the island. Some of the phenomena there seen seem to be identical with those described by Harker from the Isle of Muck in rocks of widely different age, and they throw some light upon the mechanics of intrusion.

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.

During part of 1918 the writer investigated the Cannel Coal and other possible sources of oil, together with occurrences of free Petroleum in the Yorkshire, Durham, and Northumberland coalfields, and subsequently watched the Government borings for oil in Derbyshire. The main results of this work have already appeared in sundry Geological Survey Memoirs, but some general conclusions on the subject of Petroleum in England and the facts which suggested them are here put forward. The possible oil-bearing horizons are regarded as three in number: the Lower Carboniferous rocks of Derbyshire, the Coal Measures in various fields, and the Upper Jurassic or Lower Cretaceous strata of a part of the Sussex Weald. Before giving details, a few remarks on Petroleum in general are necessary.

Calcic and alkaline eruptive rocks representing many varieties have an extensive development along the northern portion of the eastern Rift Zone in the Tanganyika Territory. They are closely similar to those better known to British geologists in Kenya Colony, and in both areas have received a considerable amount of attention from petrologists.1 In Tanganyika Territory the nearest of these occurrences to the Indian Ocean hitherto known, with one exception, to be referred to later, is more than 130 miles from the coast, and the greatest development lies at 170 to about 250 miles inland.

The Permian Basal Sands in South Yorkshire and North-East Derbyshire are very inconstant in thickness and they are often absent or unexposed over wide areas. They evidently filled eroded hollows in the Carboniferous floor and it is interesting to note that they are usually best developed where the underlying Coal Measures are soft and essentially shaly in composition. In the region under discussion some sections show the Lower Permian Limestone resting directly on the basal sand with but a slightly arenaceous base. Such is the case at the well-exposed sections east of Frickley, 15 miles north-east of Sheffield and at Harthill, 10 miles south-east of Sheffield.

During the last summer, whilst mapping the district between Nevin and Clynnog-fawr, I discovered the intrusion which is described in this communication. I can find no reference to it, either in geological maps of the Lleyn or in any geological literature, and conclude that the occurrence has not been placed on record.

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.