Much has been written about the alluvial tin deposits of Malaya by Wray, Scrivenor, Jones, Cameron, and others, but little has been published concerning the development of the country's drainage system. A complete geological bibliography for Malaya up to 1931 is given in Scrivenor's The Geology of Malaya (1931). The purpose of this paper is to record a few ideas developed by the writer during nearly five years of field work before war broke out in South-East Asia. The writer thanks Messrs. J. B. Scrivenor and E. S. Will-bourn, who read and commented upon the paper, and the Directorate of Military Survey, War Office, who supplied maps of Malaya.

The purpose of this communication is to draw attention to the possible effect of vast and synchronous volcanic eruptions and associated earth-movement, not only on local but on world climate. It is divided into two parts, the first dealing with the volcanic aspect and its particular relation to climatic changes in East Africa, and the second discussing the wider significance of the proposition and the possibly greater effect of orogenic movements on world climate when associated with volcanic episodes.

There are three main inliers of Silurian rocks in the Pentland Hills:—

(1) Lyne Water—North Esk Reservoir Inlier, which includes the Gutterford Burn section with the well-known Eurypterid and Starfish beds and the Deerhope and North Esk sections in which there is a passage upwards into red beds often referred to as “Downtonian”.

(2) Bavelaw Castle Inlier, with beds of an age similar to those in the Gutterford Burn.

(3) Loganlee Reservoir Inlier, yielding a few graptolites in strata partly corresponding with those of the Bavelaw Castle Inlier, and with an important assemblage of Silurian corals in the overlying Lower Old Red Sandstone conglomerate.

While studying the Cornish mineral deposits I have examined certain thin-sections cut from granite-porphyry dykes which contain numerous quartz or felspar veinlets. The structures in these veinlets and their behaviour towards the various constituents of the host rock are, I believe, sufficiently interesting to merit detailed description. The sequence of events to be deduced from these features is not commonly recognized, and the underlying principles may have a broader application to include some of the larger mineral veins in Cornwall.

Among the many faults in the Marlborough district of the South Island of New Zealand four, the Wairau, Awatere, Clarence, and Kaikoura faults, are of the first importance as boundaries between great elongated tectonic blocks that determine the high mountain ranges of this north-eastern corner of the South Island and the basins, or valleys, that guide the principal rivers draining it (Text-fig. 1). Modification of these major landscape features by erosion has proceeded very far, continuing, apparently, for a long time after the differential earth movements that initiated them had come to an end; but quite recently there has been a general renewal of movement on the ancient lines of dislocation, in some important cases with reversal of the sense of the earlier displacement.

This year, the 150th anniversary of Hutton's death, we are particularly reminded of the lively struggle of the eighteenth century between Vulcanists and Neptunists; the more so since that struggle finds its counterpart to-day in the divergence of opinion between two schools of petrology whose respective members might aptly be called Magmatists and Transformists. Much of the disagreement between the modern opponents arises from a belief on the part of the Magmatists that Hutton proved the magmatic origin of granite, and, in addition, the disagreement is probably strengthened by a misunderstanding of the views held by Transformists, and by lack of knowledge or experience of the evidence on which they base their conclusions. Indeed, Transformists might be tempted to preface their writings with the following very apposite quotation from Werner (1781):—

“I must here present a request to all who would judge of this theory, or communicate their sentiments on it to the public, viz. to begin by reading through the whole treatise, and then to peruse it a second time, with attention. Such a request will not only appear strange to many persons, but even superfluous ; I find myself, however, under the necessity of making it from the manner followed by some individuals with my book on the external characters of fossils. They have often represented me as saying quite the contrary of what I have expressly written. This may have been done by some, through design, but in by far the greater number of instances, it has happened from that work not having been read through ; and in this manner the public has frequently been led into an error, at least for some time.”

Much attention has been paid to composite dykes and sills during the present century, and accepted definitions of the term “composite” centre about that of Daly (1933), who has stated that composite dykes are formed by successive injection of chemically differing melts into the same fissure which widens to receive them.

The Post-Karagwe-Ankolean Granite occupies very extensive areas in South-Western Uganda and has been emplaced within two systems of sedimentary rocks. These, in order of age, are known as the Toro System and the Karagwe-Ankolean System. In their structural relations towards the granite, the two systems show striking differences one from the other, a feature which provides interesting evidence relating to the “granite problem” on a regional scale and, in addition, throws light on certain aspects of Pre-Cambrian stratigraphy.

1. The North Creake boring shows the Chalk up to the Coranguinum zone to be appreciably thicker than at the nearest outcrops. The Chalk rests upon fine-grained Upper Greensand (possibly Albian) which is developed in addition to the normal Red Chalk.

2. The “Lower Greensand” is developed much as at outcrop, but the Sandringham Sands are thickened by one-third. There is a strong indication of a stratigraphical break in the middle of the Carstone, which may mark the boundary between the Aptian and Albian stages.

3. The Kimeridge, Corallian (Ampthill), and Oxford Clays are developed as in the King's Lynn district, and (in contrast to Southerey) normal Kellaways Beds rest on Cornbrash.

4. The upper part of the Great Oolite Series is in Blisworth Clay facies. The “Limestone” is raggy and non-oolitic.

5. The Great Oolite rests directly on bituminous shales which are believed to be of early Upper Lias date. The Middle and Lower Lias are well developed, but the latter is attenuated as a whole. There is a possible representative of the Lower Rhaetic.

6. The Trias is represented by varicoloured marls (Keuper) upon pale grey sandstone (probably Bunter). The latter rests directly on pre-Cambrian rocks comparable with tuffs and agglomerates of Chamwood.

The Permian corals of Timor are of particular value on account of their excellent state of preservation which permits of close study of the skeletal structures. The works of Gerth, Koker, and Schindewolf have added much to our knowledge in this respect. In the course of my investigation on the rugose corals as a whole, I have studied a part of the Timor material in the British Museum (Natural History), upon which this present article is based, and I am grateful to the Keeper of the Department of Geology, and to Dr. H. D. Thomas for the loan of specimens, and for the privilege of cutting them in the Museum. Dr. O. M. B. Bulman and Dr. Thomas both kindly read the manuscript. To Professor W. B. R. King and Mr. A. G. Brighton I am indebted for facilities for study in the Sedgwick Museum.

The area to which this paper refers comprises that part of north Northamptonshire and Huntingdonshire lying to the east of the River Nene, not far from Oundle, 10 miles W.S.W. of Peterborough. It lies immediately east of the Northampton Ironstone Field, and is largely included in New Series, Sheet 171, and the adjacent parts of Sheets 157, 158, and 172 of the Geological Survey. The area was originally surveyed on the 1-inch scale by Judd (1875), and maps and memoirs published in 1872–6. Apart from the description of certain sections, notably by Beeby Thompson (1928, 1930) and Douglas and Arkell (1932), no subsequent work was done in this area until the Geological Survey commenced the primary 6-inch survey in 1939. During the progress of this work Survey Officers observed many structures which, by their relation to topography, were deduced to be of superficial origin. Hollingworth, Taylor, and Kellaway (1944, 1946) have given us a key to the interpretation of many puzzling features of structure and topography in the Jurassic scarplands, and it is their pioneer work which has made the present paper possible. In the area east of the Nene many of the types of structure described by those authors can be observed; there are, in addition, other structures which appear to be of similar origin, and which it is now desired to place on record.

The Geology Department of Reading University recently received four specimens of lava of the 1922 eruption at Bibundi, British Cameroons, collected in 1945 by Mr. E. D. Bumpus, a former student of the University, now of the Nigerian Agricultural Service.

In a recent paper (Nockolds, 1946) it was shown that certain granite-aplites associated with acid plutonic rocks of Caledonian age in Western Scotland fell on, or were very close to, the plagioclase-potash felspar-quartz cotectic curve (the granitic cotectic curve), the approximate position of which could be determined from experimental data now available. It seemed of interest to determine whether other granite-aplites from other areas behaved in the same way and chemical analyses of granite-aplites and related rocks were collected from the literature with this end in view.

One of the most prominent features of an ice-eroded region is the formation of a number of basins scoured out of the bedrock by the ice and rock frozen into it. When the ice has retreated these basins usually fill up with water, thus forming lakes, and Windermere appears to occupy two small basins scoured out of the floor of a valley which extends to the south as far as Cark, where it joins the coastal plain. It is, therefore, difficult to explain why the natural outflow of the lake should be through the Leven valley, a gorge extending from Newby Bridge to Haverthwaite, instead of through this broad valley which must have existed when the lake was formed (see map).

In this country the best known species of Tetradella is T. complicata (Salter), a form which is usually regarded as typical of Caradoc rocks and has been widely quoted in faunal lists as such. It happens, however, that this species was originally described as Beyrichia complicata, by Salter (Phillips and Salter, 1848, p. 352, pi. 8, fig. 16) from the Llandeilo Beds of Llan Mill, near Narberth, and it is extremely unlikely that it ever occurs in Caradoc beds. This confusion has no doubt arisen from the inaccuracies in Salter's original figure, the briefness of the accompanying description and the fact that McCoy figured what is obviously another species of Tetradella under the same name from the Caradoc Beds of Pont y Meibion (McCoy, 1851, pl. IE, fig. 3). At a later date T. R. Jones refigured T. complicata from Llan Mill with more accuracy than Salter and with a fuller description, but unfortunately figured under the same name a form from the Caradoc of Harnage, giving also a list of Llandeilo and Bala localities where T. complicata was supposed to occur (Jones, T. R., 1855, pp. 163–5, pl. vi, figs. 1–5). In addition to this figures have appeared in various textbooks and similar works of a general nature which are usually too poor for specific determination although it is obvious that in the main they cannot be referred to Tetradella complicata (Salter).

At a distance of about two and a half miles from Aberystwyth, the road leading eastwards towards Devil's Bridge curves round the north side of a small knoll on the ridge separating the larger valley of the Rheidol on the north from the smaller valley of the Paith on the south. The road here reaches a height of 400 feet and the knoll rises a further 100 feet above it. Opening directly from the south side of the road, a quarry (now disused) has been excavated in the knoll and in this quarry the Aberystwyth Grits present a very striking appearance, showing a zig-zag structure with one fold above the other.

The object of the present short paper is to draw attention to what A seems to the writer to be a rather important omission in most recent discussions of the origin and nature of granite. In these discussions the word granite or almost equally often the word granodiorite are used as if it was to be assumed that all granites are alike and all granodiorites alike. In what follows, for the sake of brevity, all will be called granites, as a general class-name, without discriminating each time on small points of petrographical difference. Now all granites are not alike, by any means. They show wide variations, not so much in their main components of quartz, felspar, and ferro-magnesian minerals (the essential minerals, according to definition), but in their minor constituents and accessory minerals and still more in some of their accompanying phenomena. By this last expression is intended not so much their metamorphic effects, in the narrow sense of the word, but what is commonly called pneumatolysis, and still more importantly, the accompanying ore-deposits, if indeed it is possible to discriminate between these two categories.

During recent work for the D'Arcy Exploration Co. the writer found it necessary to attempt to understand the structural history of the Malvern Range. The widespread conception of violent “Armorican” earth movements, almost simultaneously acting in directions at right angles to each other in a relatively small area, did not appear satisfactory. No important tectonic contribution to Malvern literature has appeared since Groom's work published in 1899 and 1900, conveniently summarized in Geology in the Field in 1910. Text books either ignore the problems completely and generalize strangely,2 or say practically nothing about them.3 To separate fact from later theory it was necessary to go back to the original surveys. As a result the writer finds himself unable to accept Groom's conclusion on the age of the movements causing the overturning, and in places imbrication, of the Silurian and Lower Old Red Sandstone rocks on the west side of the range. He is also strongly of the opinion that the evidence for the great Malvern Fault, separating the Trias from the older rocks on the east side of the range, has been much overplayed.