It is established that the Dawros peridotite of north Connemara contains basic plagioclase mainly in a gabbroic layer in the peridotite but occasionally as rare crystals in the peridotite itself. Carlsbadalbite twin extinction angles indicate that the composition of this feldspar is similar to that in the adjoining Currywongaun-Doughruagh intrusion and that in the ultrabasic rocks of the Cashel-Lough Wheelaun intrusion and the Roundstone intrusion of south Connemara. As all these feldspars are extremely heavily saussuritized because of metamorphism it is difficult to determine their precise composition and so an exceptionally fresh plagioclase from an anorthosite in the Currywongaun-Doughruagh intrusion has been chemically analysed. It is An91·5Ab6·8Or1·7. This is in close agreement with the composition given by measuring 2θ(131)–2θ(131), the refractive indices and 2V while the extinction angles of Carlsbadalbite twins give only a slightly too anorthitic result (An95). The particularly calcic nature of the plagioclase is strong evidence that all the ultrabasic bodies in Connemara are genetically related. Some new structural ideas on the Dawros body are suggested which integrate the structure, petrography and cryptic variation.

Abundant spherules of phengite, 50—150 μm in diameter and with a radial texture, occur in mudstones at the top of the lowest member of the Bonahaven Formation. They have smooth, sharp boundaries, show flattening next to desiccation cracks and exhibit a restricted, bi-or tri-modal size distribution. It is inferred that the spherules represent infilled voids in a sediment which was deposited entirely from suspension. Accordingly, it is considered likely that the spherules are microfossils, although characteristic morphological features are lacking. They were probably infihled by glauconite, which was transformed to phengite during diagenesis and low-grade metamorphism.

Three heavy mineral associations have been recognized in Palaeogene sands from the Hampshire Basin: one typical of the Scottish Highlands to the north, one of the Armorican massif to the south, and one characteristic of the Cornubian massif to the west. These associations interplay throughout the sequence to produce 10 heavy mineral units correlatable over the basin. The bases of several of the units correspond to commonly accepted time-surfaces and encourage correlation between areas showing strong facies variation. Transgressive units are dominated by Scottish-type material, regressive units by Armorican or Cornubian detritus. There is a relationship between local source area uplift and regression, the main reason for which is that the widespread transgressions submerged or otherwise cut off more local sediment sources, allowing input from the Scottish Highlands, a positive feature throughout much of Tertiary time, to dominate.

The recent reinterpretation of the structure of Rum presented by E. B. Bailey (1944) involves a revision of the age of the gneisses of that island. Harker's description of these banded and foliated rocks had referred them to a late date in the Tertiary igneous sequence of the plutonic centre (Harker, 1908). This interpretation had been arrived at in face of the earlier belief of Geikie that they formed part of the Lewisian Series and it is now known that Harker's contemporaries on the Geological Survey who had opportunity of examining his collections dissented from his conclusions though this opinion had until recently not been committed to print (Flett, 1944).

The two most commonly used biostratigraphic standards for the Campanian–Maastrichtian boundary are the appearance of the belemnite Belemnella lanceolata (Schlotheim) and the disappearance of the planktic foraminiferan Globotruncanita calcarata (Cushman). The first is a boreal standard, the second tethyan. The assumption that the two coincide is false. In Mississippi the disappearance of G. calcarata is the same eustatic peak of sea-level which in north Germany lies near the top of the Nostoceras polyplocum Zone, within boreal nannofossil Zone CC/B22. This places the foraminiferal standard somewhere between 1.3 and 3.5 m.y. older than the belemnite standard. The belemnite standard is at or close to the appearance of Gansserina gansseri (Bolli) in Mississippi.

The Coombadjha Volcanic Complex is the remnant of a Late Permian cauldron. It is part of an extensive sequence of silicic calc-alkaline volcanics that covers the southeastern portion of the New England Orogen in NSW. The Complex is elliptical, measuring 15 × 24 km, and is outlined by a ring pluton and an arcuate fault. Bedding in the volcanic units of the Complex defines a structural basin, with steep inward dips at the monoclinal rim and gentle to horizontal orientations near the centre. An older group of outflow ignimbrites, lavas, breccias and volcaniclastic rocks at least 1500 m thick, is conformably overlain by more than 500 m of texturally homogeneous, crystal-rich, dacitic ignimbrite. Ignimbrites of the older group are the products of several discrete eruptions from separate vents, all of which were situated outside the Coombadjha area. Silicic lava domes with volcaniclastic aprons, and a tuff ring, mark the positions of local vents active on a small scale during intervals between the emplacement of the outflow ignimbrites. No significant subsidence occurred, nor did a caldera exist at this stage. Cauldron subsidence occurred in response to the large magnitude eruption that produced the crystal-rich ignimbrite. The central cauldron block was lowered at least 2000 m by downwarping and fault displacement, and remained largely intact. There is no evidence for resurgent doming of the cauldron after subsidence, although igneous activity continued with intrusion of an adamellite ring pluton along much of the cauldron margin. The crystal-rich ignimbrite and the ring pluton are similar in composition and may have been successive products of a common magma source that sustained this simple, single cauldron cycle.

The growth of our knowledge of the gigantic extinct birds of Madagascar has been a very slow one. The first notice of their occurrence was published in 1851 by I. Geoffrey St. Hilaire; but it is only within the last two or three years that any part of their skeleton, except the bones of the leg and some very imperfect vertebrae, has been described. Eecently, however, the collections that have reached the Museum of Natural History at Paris, and those obtained by Dr. Forsyth Major for the British Museum, have filled most of the gaps, and all the important parts of the skeleton are now known.

Abundance data, determined by epithermal neutron activation analysis, are reported for radioelements in the northern units of the Leinster granite. Compared to similar data for silicic igneous rocks and British Caledonian granites, the Leinster granite shows normal U and K contents but is low in Th. Inter-element correlations and fission-track results suggest that most Th and up to 40% of the U is bound in resistate accessory phases (zircon, sphene, apatite), but that the bulk of U is associated with late-stage alteration products and is located at interstitial labile sites within the host-rock matrix. Mobilization of U located at such sites in the Leinster granite by hydrothermal leaching could lead to redeposition and enrichment in marginal sediments of Old Red Sandstone or younger age.

The rocks composing Basutoland belong to the Stormberg Series of the Karroo System. They cover a much larger area than Basutoland, extending into the Orange River Colony on the west and north, on the south and east into Cape Colony and Natal, and, I am informed, across the Vaal into the Transvaal. The area is thus not less than 45,000 square miles. The whole of that part of the Orange River Colony known as “the Conquered Territory,” east of a line drawn from Thaba 'Nchu to Vrede, is occupied by the whole or portions of these rocks.

The Upper Ordovician Kyrkås Quartzite Formation at the Nifsåsen Quarry (Jämtland, Sweden) exhibits c. 90 m of siliciclastic sedimentary rocks deposited on a shallow shelf at the craton-attached part of the Caledonian foreland basin. Five lithologies are distinguished, including claystone, mudstone, siltstone, subarkose and sublitharenite. Based on these five lithologies, sedimentary structures and biota, three marine facies associations are defined: the Mudstone association (FA1) deposited close to storm wave base, the Sandstone/mudstone association (FA2) formed between storm and fair-weather wave bases, and the Sandstone association (FA3) accumulated above fair-weather wave base. The facies associations are arranged in two sequences, c. 50 and 40 m thick, separated by a transgressive surface, indicating repeated shoreline progradation. Both sequences commence with marine heterolithic shales and siltstones, with upwardly increasing frequency of tempestites. Continued shoaling is indicated by a dominance of hummocky and trough (locally tabular) cross-stratified sandstone beds in the upper part of each sequence. Sand beds are increasingly amalgamated up-sequence, reflecting progressively diminishing accommodation space. The depositional style and sedimentary structures indicate that the study area was storm-dominated with an abundant supply of siliciclastic material. Biostratigraphic data tie the depositional changes to the globally recognized Late Ordovician (Hirnantian) glacial interval. These data suggest that the first sequence was formed during the initial phase of regression in the earliest Hirnantian. The lowermost part of the overlying sequence contains elements of a typical Hirnantia fauna followed by beds yielding Normalograptus persculptus, suggesting a second regressive cycle in the Jämtland basin during the early N. persculptus Biozone.

A sheeted dolerite dyke swarm has been discovered at Duniewick Fort, Ballantrae. It forms part of the Early Ordovician Ballantrae Complex of Ayrshire, southwest Scotland. Asymmetric chilled margins, parallel to sub-parallel dykes and multiple dykes (dykes within dykes) are found. Although the mineralogy has been altered by metamorphism, the geochemistry is comparable with modern day back-arc marginal basin basalt. Cross-cutting sills have the chemistry of within-plate basalt. The regional geological setting suggests that an ophiolite sequence has been dismembered and incorporated into a serpentinite mélange. This is the first description of a 100% sheeted dyke complex (senso stricto) from the Ballantrae ophiolite.

The Woolridge Terrace gravels of the lower Severn are re-examined, and certain high-level gravels west of the Severn valley examined for the first time. It is concluded that the deposits are of two different ages. The older series is probably the outwash of a Severn valley glacier, the younger was laid down by a stream coming from the Silurian hills near Ledbury. A Gipping age is suggested for both.

On pages 20–2 and 99–105 of the Geology of the Gold Fields of British Guiana I gave a condensed account of the residual earths derived from the gradual decomposition of igneous rocks in situ which characterize wide areas ia British Guiana as well as in the neighbouring countries of Venezuela, Dutch Guiana, French Guiana, and Brazilian Guiana. This deposit forms in many places a widespread very thick blanket-like coating to the igneous rocks from which it is derived, and owing in many places to its striking resemblance in general properties to the typical Indian formation described by Buchanan in 1807 it has been alluded to by many authors and by numerous mining engineers as ‘laterite’. I gave on p. 101 two analyses of lateritic deposits which I selected from many I had made as showing the general composition of the earths. Unfortunately I omitted to show in them separately, as I had done in the original analyses, the proportions of silica present as quartz and of that present in a combined state. If I had done this it would have been seen that the earths contained but little combined silica and a relatively high proportion of alumina presumably present in the state of hydrate. For instance, in the Tumatumari sample which I collected myself from a deep cutting in the laterite lying on the diabase of the Tumatumari cataracts a few feet only above the surface of the unaltered rock, out of 51·76 per cent. of silica 49·35 is in the form of quartz, leaving 2·41 per cent. in the combined state in the presence of 24·55 per cent. of alumina.

The role played by Cenozoic deformation in denudation and landscape development in Ireland has historically been difficult to assess because of the lack of widespread pre-glacial Cenozoic deposits onshore. Here we combine analysis of apatite fission-track data and geomorphic observations to place constraints on the timing, kinematics and magnitude of onshore deformation in southeastern Ireland. Relationships between apatite fission-track central age and elevation for samples from the Wicklow and Blackstairs Mountains and Tullow Lowland suggest that these rocks record an exhumed apatite partial annealing zone, which after cooling was dismembered by differential vertical displacements of up to several hundred metres. We use inverted models of sample thermal history to show that samples across the region experienced very similar thermal histories up to and including a cooling event in late Paleocene or early Eocene time. This effectively rules out strongly spatially heterogeneous denudation, and implies that differential rock uplift occurred in post-early Eocene time. The central age–elevation relationships define at least three spatial domains with internally consistent apatite fission-track data, separated by known faults or topographic escarpments. Geomorphic analysis of these structures shows that patterns of catchment incision and sinuosity, as well as the presence of antecedent drainage, are best explained by differential vertical displacements at or near the domain boundaries. The kinematics and magnitudes of these displacements are consistent with those implied by the apatite fission-track results, and are compatible with other examples of known Cenozoic deformation from Ireland and the adjacent continental margin.

A representative collection of fossils from the Middle Cambrian beds of Mount Stephen, Field, British Columbia, has recently been brought back by Mr. S. H. Reynolds, M.A., F.G.S., and presented to the Woodwardian Museum. The fauna has been described by Rominger and Walcott; and the latter has compared it to that from the Highland range, near Pioche, Nevada, and from near Antelope Spring, Western Utah. The section at Field has been described by Mr. E. G. McConnell.

Image analysis is rapidly becoming an integral part of scanning electron microscopy. A number of analogue and digital image analysis systems of varying sophistication are now commercially available for the SEM. This paper illustrates how one such relatively simple system, the IMAS image analyser manufactured by Cambridge Technology, can be used to obtain rapid quantitative estimates of porosity and mineral abundance in backscattered electron images of polished rock sections.

For some years past a Committee of Littleborough and Rochdale geologists, consisting of Messrs. W. H. Sutcliffe, Walter Baldwin, W. A. Parker, S. S. Platt, and others, have devoted themselves to the task of working out the beds of shale containing clay-ironstone nodules, a portion of the Middle Coal-measures at Sparth Bottoms, half a mile south-west of Rochdale Town Hall, in beds estimated to occur 135 feet above the Royley Mine Coal-seam.

In the clay-ironstone nodules occur well-preserved ferns, Calamites, Sigillariœ, shells of Carbonicola acuta and other Coal-measure lamellibranchs, whilst the number of Arthropoda obtained is probably unsurpassed in any locality of this formation.

The first Arthropod obtained from Sparth Bottoms was noticed by Mr. Walter Baldwin, F.G.S., under the name of Prestwichia, rotundata, Prestw., sp. (Trans. Manch. Geol. Soc., vol. xxvii, part 6, 1901, pp. 149–155, with a plate); the second in 1903, by the same geologist, who identified it as Bellinurus bellulus, König (op. cit., vol. xxviii, part 8, pp. 198–202). The third and most important discovery was made by Mr. W. A. Parker, F.G.S., namely, a new species of fossil Scorpion, which was described and figured in 1904 by Messrs. Baldwin & Sutcliffe under the name of Eoscorpius Sparthensis (Quart. Journ. Geol. Soc., vol. lx, p. 396, fig. 2). These geologists have continued their researches, of which a brief account was given by me at the York Meeting of the British Association (1906). Many subsequent finds have been most obligingly confided to me by these gentlemen, and through the kindness of Mr. W. H. Sutcliffe the specimens figured have since been presented to the Geological Department of the British Museum (Natural History), the only condition imposed being that they should be described.

The curious little shield-like Crustaceans, known under the generic name of Cyclus, were first noticed by de Koninckin1841, and have been subsequently figured and described by various authors, but their exact systematic position lias never been clearly understood owing to the absence of appendages or other indications by which their affinities might be satisfactorily ascertained.

In 1868 I gave a description, with figures, of two species:' one of which, the Cyclus radialis, had been previously noticed by de Koninck and Phillips; the other, C. Bankini, was then first made known.

In 1870, under the title of “Contributions to British Fossil Crustacea,” I redescribed the above-named species, and added Cyclus bilobatns, C. torosus, C. Jonesianus, C. Wriyhtii, C. Harknetsi, C. (Halicyne) laxus, C. (Halicyne) agnotus.

The next record of the genus is to be found in the fifth part of my Monograph of British Fossil Crustacea of the order Merostomata, which records and figures the then known seven British species of Cyclus, but adds no new forms.

In 1883 Mr. B. N. Peach, F.K.S., L. and E., F.G.S., published an account of Cyclus testudo, from the Carboniferous series of Langholm, to which reference will again be made later on.

In 1893 I noticed a new British species of Cyclus, discovered by Mr. George Scott in the "Gannister seam" of the Lower Coal-measures, Old Clough Colliery, Bacup, Lancashire, which I named Cyclus Scotti.

In the same year Mr. F. E. Cowper Eeed, B.A., F.G.S., of Trinity College, Cambridge, gave a description of what he deemed to be probably a new species of Cyclus, from the Carboniferous Limestone of Settle, Yorkshire, near to, but not identical with, C. Harhiessi, which he named V. Woodwardi.

The Honggong pluton is the largest ferroan alkalic (A-type) granite intrusion emplaced along the Jiangshan–Shaoxing fault zone in southwestern Zhejiang Province, and has important implications for understanding the Late Mesozoic tectonic evolution of SE China. U–Pb ages of 138.7 ± 0.8, 134.2 ± 1.1, 128.5 ± 1.5 and 126.1 ± 0.9 Ma were obtained from zircon by laser ablation–inductively coupled plasma–mass spectrometry, indicating that the Honggong pluton formed in the Early Cretaceous. The Honggong pluton has a clear ferroan alkalic (A-type) granite geochemical signature with, for example, high total alkali contents and FeOt/(FeOt + MgO) values. The Sr–Nd–Hf isotopic compositions suggest that there was juvenile material in the magma source. Geochemical evidence indicates that the pluton was derived through extensive fractionation of melts that contained both asthenospheric mantle and Mesoproterozoic crustal components. These rare granites in southern China were emplaced during five episodes at 235–225, 190, 165–155, 100–90 and 140–120 Ma. The age of the Honggong pluton suggests that localized extension in southwestern Zhejiang Province began as early as ~138 Ma and continued to 126 Ma. This Early Cretaceous extensional event was triggered by localized rollback of the subducting Pacific Plate.

Rhythmic layering in which the layers grade from coarse base to finer top is described in a plagioclase—pyroxene—olivine gabbro. The medium sizes of the various cumulus minerals at each level have significantly different settling velocities. Variation in the proportions of the cumulus minerals accompanies the size grading. It is shown that these characteristics can reasonably be accounted for if hydrodynamic factors exerted the main control, over-riding any chemical effects.