In the course of a voyage across the Pacific in September, 1924, from Vancouver to New Zealand, I broke my journey at Suva for four weeks with the object of seeing something of the geology and scenery of Viti Levu. Half that time, however, was spent in a cruise to the Tonga Islands and Samoa, leaving therefore only a fortnight for Viti Levu, but His Excellency the Acting Governor, the Hon. T. E. Fell, C.M.G., gave me facilities for visiting the mountainous country of the interior which enabled much more of the island to be seen in that short time than would otherwise have been possible. To him and to other officers of the Government who assisted me in my tour I offer my best thanks. Mr. F. R. Charlton, the Acting Crown Surveyor, accompanied me on my coastwise journey and in a traverse across the island from north to south. His knowledge of the country and of the Fijian language and customs was invaluable. Major Caldwell, Mr. Reay, and Mr. Armstrong, the District Commissioners through whose areas we padded, gave us hospitality and every assistance possible, and Mr. Boyd, the Commissioner for Native Affairs, made arrangements with Fijian chiefs, in whose houses we were charmingly and hospitably entertained. When making the tour I had no intention of writing any account of it for publication, but several new facts came to light which it is desirable to place on record.

Gypsum or selenite is one of the commonest “decomposition” minerals found in connexion with the exposed surfaces of the Tertiary rocks in southern Ecuador. With the possible exception of the coarser grits and conglomerates, the normal sandstones are usually veined extensively by sheets of this mineral; it also occurs in a fibrous form (plates), in agglomerations of minute scalenohedrons, flake-like folia parallel to the bedding, and also in beautiful rosette-like or “stellate” groupings. In the typical clay shales or “gredas” the distribution of gypsum is not so general, though crystals or irregular groups of imperfectly shaped crystals occur on the weathered slopes or screes. In many localities, where a steep talus slope of shale forms the foot of a superimposing sandstone cliff, the scree itself is invariably covered with broken plates of gypsum in such profusion that from a distance it has the appearance of irregular masses of ice or glass. The platy form (which usually consists of parallel laminae with vertical fibres) is probably the most common and, in reality, each plate has been formed after the manner of a typical vein deposit.

A preliminary account of the subject of this paper was given before Section H of the British Association at the Oxford meeting in 1926 (1, 2).

Four species of Monograptus are described and the age of the strata shown to be that of the zone of M. nilssoni of the Lower Ludlow of Great Britain.

In recent years Professor J. W. Gregory has challenged, one after the other, our most cherished beliefs and creeds in the field of glacial geology, fearlessly raising again the discarded standards, dust-laden these many years; the gaping fissures of the fjords, the glacial submergence, the residual character of many moraines, eskers, and kames, including the beautiful York moraines, and now —the post-glacial origin of drumlins.

Since the publication of the paper by the present author in 1905 on the Classification of the Phacopidae, a considerable advance has been made in our knowledge of this family as a result of further and better material being obtained, and of new discoveries in different parts of the world. Many new genera and subgenera have been instituted, and modifications or limitations of some of the old terms have been introduced by various authors. The work of Wedekind, Clarke, Rud. and E. Richter, and Kozlowski has specially dealt with questions of classification, but there is still a considerable amount of diversity in the usage and application of the generic and subgeneric names.

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.

So far as the writer is aware, no sodic or “contaminated” rocks have been recorded from Iceland, and it was thought that an examination of some black sand collected by Dr. L. Hawkes, and kindly supplied by him, might reveal the presence of minerals from such rocks.

The foregoing sketch brings out marked resemblances in the geological features of eastern and southern England on the one hand, and the neighbouring parts of the continent on the other. In both areas we find an old plateau of pre-Devonian rocks, against which Devonian and Carboniferous rocks are violently thrust from the south by Armorican and Variscan folds, giving rise to highly complex coal-basins in Belgium, France and Somerset, a type of structure possibly to be encountered in the future in Kent. In Belgium this plateau sinks to the north-east under the Campine coalfield, while in England its north-west margin is complicated by the incidence of posthumous folds of Charnian strike.

In eastern England, east of the Charnwood line, there is evidence for the existence of Professor Kendall's Willoughby axis, with north-west strike; between this and the Charnwood line there are indications of similar parallel buried trend-lines in the folding and faulting of the visible Yorks-Derby-Notts coalfield, and also, as suggested by Professor Fearnsides, in the general shape of this basin.

Further to the north, however, the general line of the Cleveland and Market Weighton axes is not Charnian, being about west 5° north. The Market Weighton axis, which is of Charnian type, with many repeated movements, does not form the boundary of the coalfield; this is in fact constituted by the southern flank of the broad Cleveland uplift, which is of Wealden type; an anticline superposed on an earlier sinking area.

In 1844 M'Coy subdivided the genus Spirifer Sowerby into five groups, two of which, Brachythyris and Martinia, were characterized by “the presence of a hinge-line shorter than the width of the shell”. Brachythyris included forms “in which … the longitudinally-ribbed surface of Spirifera is united with the short hinge line of Martinia”. The latter included “the smooth spirifers”. M'Coy's subdivisions, however, have not been much used. More recently Mr. S. S. Buckman2 has shown that the smooth forms grouped by M'Coy and others in Martinia are the catagenetic members of several spiriferid stocks. Buckman considered that Martinia and Brachythyris were distinct from the other spirifers in their shape and in their lack of dental plates.

The genus Promicroceras was separated from Xipheroceras by Dr. L. F. Spath to include Ammonites capricornoides and the Am. planicosta group. The researches of Dr. W. D. Lang on the Dorset coast have shown that the genus Promicroceras persists with relatively slight changes from the “birchi” zone up to the “ziphus” zone.

At the commencement of the year 1925 the Post Office authorities, for the purpose of laying down telephone lines, were making a trench from the corner of Rochester Road (Camden Town) north-eastward up the Camden Road and across it into and along Murray Street in the direction of St. Paul's Road, and were laying ducts at the depth of about 10 ft. The distance from the corner of Rochester Road to a point opposite the corner of Murray Street is 160 yards, the direction north-east, with a slight rise in that direction. Previously the London County Council tramway cable ducts had been laid down to the depth of 3 ft. 6 in., but below this level the whole of the ground excavated was in an undisturbed state. The trench was 2 ft. 7 in. wide. A man-hole had been sunk at the corner of Rochester Road, another at the end of the works on the Camden Road, and a third opposite to it at the corner of Murray Street, all to a depth from the surface of more than 12 ft. In fact the Camden Road man-hole was sunk to the depth of 15 ft. 6 in., so as to enable the excavators to tunnel under the road to Murray Street in order that the stream of traffic along the Camden Road might not be disturbed.

Mr. J. V. Harrison, B.Sc., has recently collected some coral limestones from two localities in Venezuela, which he has entrusted to me for identification and description. The corals indicate the existence in eastern Venezuela of a rich fauna, for the specimens include fragments of seven genera. Some of the corals are too small for specific, and some for certain generic determination but as there appears no likelihood of further material being collected, it seems advisable to describe what is available to direct attention to an interesting and varied coral fauna. The two localities represented are Port Piritu, on the shore of the great bay west of the town of Barcelona in eastern Venezuela, and Punceres to the west of the Gulf of Paria between the two branches of the Rio San Juan and due west of the lower course of that river. A map, for which I am indebted to the Anglo-Persian Oil Co., through Mr. S. Lister James, shows that the position of Punceres is at about 10° N., 631/2° W. The corals were collected during surveys made for that Company, which has paid for the accompanying plate.

The district dealt with in this paper includes the coastal region of Cardiganshire, and that part of the county which lies to the south-west of a line drawn from Aberporth on the coast to Newcastle Emlyn in the Teifi valley.

The chemical environment of vesuvianite and grossular is typically revealed in their associated minerals, calcite, diopside, scapolite, and wollastonite, characteristically developed under the physical conditions prevailing in thermal metamorphism.

The following is a very brief summary of the results of my investigation of the problems here dealt with:—

(1) The limestone is Carboniferous or Permo-Carboniferous or more probably both.

(2) All the limestone belongs to one continuous phase of deposition.

(3) The “Schist Series” is above the limestone, and is of Triassic age.

(4) The western boundary of the limestone is a great fault or system of faults.

(5) The thickness of the limestone is indeterminable, but is probably to be measured by thousands of feet.

(6) The limestone hills are due to overfolding from the west, modified by block-faulting and denudation.

(1) The clay pebble bed of Ancon (Ecuador) is essentially a true deposit, probably formed, in the first place, by the denudation of an Eocene land surface under abnormal climatic conditions.

It has not been formed primarily by overthrusting or shearing, although these tectonic phenomena have undoubtedly affected the deposit at a later stage of its history.

(2) The clay pebble bed does not attain a thickness of more than three hundred feet, and it is included in about eighteen hundred feet of uniform clay shales and sandstones. The evidence collected from the drilling of boreholes suggests that recumbent folding has taken place in this area. No other explanation can satisfactorily account for the presence of two (or three) phases of the clay pebble bed in the same borehole. (Fig. 1.)

(3) Whilst stratification is not usually present in the clay pebble bed, a certain linear arrangement of the constituent materials has been detected which indicates a flowage in the deposit prior to consolidation. Later folding, however, has obliterated most of the evidences of original accumulation.

(4) Irregularities in the present attitude of the clay pebble bed and its associated strata (such as, for example, the upper limit of the clay pebble bed transgressing the bedding planes of the superincumbent strata, the upper limit apparently being a thrust plane from which minor thrusts branch into the upper block, the presence of transitional stages, etc., where the tearing away of the sole of the upper block is visible) can all be explained by an appreciation of the special tectonics of this area, which includes the theory of recumbent folding.

One hundred and thirty-two shells of Athleta (Volutospina) spinosa (L.), have been examined, the majority being well enough preserved to permit of detailed measurements being made. The variation in the breadth/height ratio was found to indicate an increase with the age of the individual, approximately according to the equation B = 0·4444h + 0·00256h + 0·000027h. Spire height expressed as a percentage of the height is greatest in young shells, those less than one centimetre in height having values of thirty-three and thirty-four per cent, whereas fully grown individuals have a mode of twenty-seven per cent.

The variations in ontogeny are not considerable, in only one case have the differences from the normal type been recognized by earlier writers as worthy of specific distinction. It is probable that Athleta (Volutospina) trisulcata (L.) is a variety of Athleta (Volutospina) spinosa.

The correlation between the various ontogenetic factors is small, for example, that for the incidence of the fifth tubercle and its disappearance is only — 0·144. On the whole the variations in each of the several characters are independent of the variations in the other characters.

This series of specimens is clearly a group in which the latitude of variation is small, and may be contrasted with such groups as that of Planorbis multiformis, in which the variation was described by Professor Hickling (9).

I wish to thank Dr. A. E. Trueman for much helpful criticism and advice during the progress of this work, and Professor E. J. Evans, of the Physics department in this college, for the use of apparatus.

The Lower Carboniferous rocks of the Craven Lowlands are predominantly fine-grained dark argillaceous limestones and calcareous mudstones and shales with a fauna of Zaphrentid or Caninoid phase. At various horizons and along various belts these argillaceous rocks are replaced by reef limestones and the associated crinoidal limestones, reef sands, and “calcaire grumeleux”. These lisnestones usually contain a specialized reef fauna or more rarely the standard coral-brachiopod fauna.