Mines near Culross, in Fife, have traversed a vent of Upper Limestone Group (Namurian) age at levels estimated to be 150 to 250 feet below the contemporary surface. The vent-filling comprises a central basaltic tuff, and a marginal lithic tuff derived entirely from the Carboniferous sedimentary rocks. A sill-like body of lithic tuff has been intruded beyond the vent margins. In sediments outside the vent post-volcanic subsidence has generated small faults; these become flat-lying or undulating where they traverse mudstones and siltstones that are inferred to have been incompletely indurated at the time of the subsidence. The volcanic and post-volcanic processes are discussed in the light of Cloos' interpretation of Swabian volcanism.

Several aspects of the Queensland serpentinites are discussed, including the significance of a suite of serpentinite-breccias, the formation of antigorite, and the general problem of serpentinization and mode of emplacement of the ultramafic rocks.

Quartz-rich xenoliths hosted in the basaltic–andesitic and andesitic lavas of Monte dei Porri, in the island of Salina, contain fluid and melt inclusions whose study makes it possible to trace back the magma ascent path of this volcano; moreover, they are a source of information about the anatectic processes that occurred under this island. The texture, mineralogy and whole-rock chemistry of these rocks exhibit the typical characteristics of a residual rock which went through several melt extraction events. The chemistry of melt inclusions hosted inside quartz grains (SiO2>72.7%, Al2O3=9.0–13.5%, CaO=0.2–4.3%, K2O>3.1%, MgO, FeOt≤1.5%) supports the hypothesis that a progressive and continuous anatectic processes affected a peraluminous high-grade metamorphic rock (gneiss or micaschist), that constituted the Calabro–Peloritani basement and generated a quartz-bearing residue. The fluids trapped inside these inclusions are rarely composed of high-density CO2, with a homogenization temperature to liquid phase (ThL) within the range 26.2–31.0°C, corresponding to densities of 520 to 690 kg/m3. More commonly, they are made up of low-density CO2, with a homogenization temperature to vapour phase (ThV) within the range 13.2–31.0°C, corresponding to density values of 150 to 460 kg/m3. It is proposed that, during ascent, batches of magma rising from the mantle sampled various fragments of a residual rock from a depleted metamorphic basal layer and carried them to the surface. Magmas probably stopped inside at least two distinct reservoirs located at different depths (≤12.7 km and between 1.7 and 4.7 km), in which they underwent fractional crystallization. The ascent speed of the xenolith-bearing magmas from the deeper storage area to the shallower reservoir was fairly high, as confirmed by the low number of high-density fluid inclusions preserved that show re-equilibration features, and by the contemporaneous presence of denser cumulitic Ol+Cpx±Opx xenoliths in the host lava.

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.

A rationalized lithostratigraphy for the Great Scar Limestone Group of the southeast Askrigg Block is established. The basal Chapel House Limestone Formation, assessed from boreholes, comprises shallow-marine to supratidal carbonates that thin rapidly northwards across the Craven Fault System, onlapping a palaeotopographical high of Lower Palaeozoic strata. The formation is of late Arundian age in the Silverdale Borehole, its northernmost development. The overlying Kilnsey Formation represents a southward-thickening and upward-shoaling carbonate development on a S-facing carbonate ramp. Foraminiferal/algal assemblages suggest a late Holkerian and early Asbian age, respectively, for the uppermost parts of the lower Scaleber Force Limestone and upper Scaleber Quarry Limestone members, significantly younger than previously interpreted. The succeeding Malham Formation comprises the lower Cove Limestone and upper Gordale Limestone members. Foraminiferal/algal assemblages indicate a late Asbian age for the formation, contrasting with the Holkerian age previously attributed to the Cove Limestone. The members reflect a change from a partially shallow-water lagoon (Cove Limestone) to more open-marine shelf (Gordale Limestone), coincident with the onset of marked sea-level fluctuations and formation of palaeokarstic surfaces with palaeosoils in the latter. Facies variations along the southern flank of the Askrigg Block, including an absence of fenestral lime-mudstone in the upper part of the Cove Limestone and presence of dark grey cherty grainstone/packstone in the upper part the Gordale Limestone are related to enhanced subsidence during late Asbian movement on the Craven Fault System. This accounts for the marked thickening of both members towards the Greenhow Inlier.

The Famennian (Upper Devonian, c. 372 to 359 Ma) strata of Belgium have recently received much attention after the discoveries of early tetrapod remains and outstandingly preserved continental arthropods. The Strud locality has yielded a diverse flora and fauna including seed-plants, tetrapods, various placoderm, actinopterygian, acanthodian and sarcopterygian fishes, crustaceans (anostracans, notostracans, conchostracans and decapods) and a putative complete insect. This fossil assemblage is one of the oldest continental – probably fresh-water – ecosystems with a considerable vertebrate and invertebrate diversity. The study of the palaeoenvironment of the Strud locality is crucial because it records one of the earliest and most important phases of tetrapod evolution that took place after their emergence but before their terrestrialization. It raises the question of environmental and ecological conditions for the Devonian aquatic ecosystem and the selection pressures occurring at the onset of tetrapod terrestrialization. The present study characterized the fluvial facies of the Upper Famennian sedimentary rocks of Strud and the surrounding areas. The exceptional preservation of arthropods and plants in the main fossiliferous layers is explained by rapid burial in the fine-grained sediment of the quiet and confined flood plain environment. Newly investigated fossiliferous sections in the Meuse–Samson area led to the description and correlation of key sections (Strud, Wierde and Jausse sections, complemented by the less continuous Haltinne, Huy and Coutisse sections). Moreover, the investigated sections allowed a review of the age of the fossiliferous horizon, which is now definitely considered to be Late Famennian in age.

It is now about forty years since the completion of the late Sir Aubrey Strahan's Geological Survey Memoir on the Isle of Purbeck and Weymouth, published in 1898. All those who, like the present writer, have known the Dorset coast from boyhood and have carried Strahan's maps and memoir over most of the ground many times cannot have failed to learn from them lessons of incalculable value. They will have come to regard the memoir as a model of scientific method and of lucid presentation, a classic not to be questioned save in matters of palaeontology, now necessarily out of date.

Values of quartile deviations (QDa) and medians (Mdmm) have been calculated from over 400 grain-size distributions of modern and ancient turbidites. Each QDa–Md pair is plotted on double-log paper to establish any distinctive trends. The QDa–Md analysis of modern turbidites reveals a steep gradient trend derived from the grain-size distributions of submarine canyon and delta fan sediments, and a shallow gradient trend derived from the grain-size distributions of samples from oceanic bottoms and nepheloid water layers. The QDa–Md analysis of ancient turbidites reveals two trends, but these do not coincide with their modern counterparts. The steeper gradient trend is related to distal and proximal turbidites, while the shallow trend is related to fluxoturbidites. The disparity between the ancient and modern QDa–Md analyses is caused by textural modifications of turbidites by diagenetic disintegration of unstable minerals. The alteration products are incorporated subsequently in the matrix. The diagenetic effects on the positions of the QDa–Md plots are demonstrated theoretically by computing the textural alteration of six modern turbidites by assuming that they will lose 20%, and then 40%, of their sand-sized particles to the matrix. By working in reverse the QDa–Md plots of ancient turbidites can be ‘restored’ to their diagenetically unaltered positions. Their restored positions correspond to the QDa–Md trends of modern turbidites.

40Ar/39Ar in situ UV laser ablation of white mica, Rb–Sr mineral isochrons and zircon fission track dating were applied to determine ages of very low- to low-grade metamorphic processes at 3.5±0.4 kbar, 280±30°C in the Avalonian Mira terrane of SE Cape Breton Island (Nova Scotia). The Mira terrane comprises Neoproterozoic volcanic-arc rocks overlain by Cambrian sedimentary rocks. Crystallization of metamorphic white mica was dated in six metavolcanic samples by 40Ar/39Ar spot age peaks between 396±3 and 363±14 Ma. Rb–Sr systematics of minerals and mineral aggregates yielded two isochrons at 389±7 Ma and 365±8 Ma, corroborating equilibrium conditions during very low- to low-grade metamorphism. The dated white mica is oriented parallel to foliations produced by sinistral strike-slip faulting and/or folding related to the Middle–Late Devonian transpressive assembly of Avalonian terranes during convergence and emplacement of the neighbouring Meguma terrane. Exhumation occurred earlier in the NW Mira terrane than in the SE. Transpression was related to the closure of the Rheic Ocean between Gondwana and Laurussia by NW-directed convergence. The 40Ar/39Ar spot age spectra also display relict age peaks at 477–465 Ma, 439 Ma and 420–428 Ma attributed to deformation and fluid access, possibly related to the collision of Avalonia with composite Laurentia or to earlier Ordovician–Silurian rifting. Fission track ages of zircon from Mira terrane samples range between 242±18 and 225±21 Ma and reflect late Palaeozoic reburial and reheating close to previous peak metamorphic temperatures under fluid-absent conditions during rifting prior to opening of the Central Atlantic Ocean.

Peak metamorphic conditions (up to sillimanite grade) in a unit of rocks beneath the evolving Kalak Nappe Complex (Finnmarkian Caledonides) developed prior to its incorporation as a nappe within the complex. The presence of displacement textures in peak metamorphic por-phyroblasts indicates that they grew in a hydrostatic stress regime and thus that the emplacement of tectonically higher units caused little or no deviatoric stress in the footwall rocks except close to the thrust plane.

The developing geotherm in the incipient nappe was disrupted by the onset of thrusting (D2 deformation), which placed hot rocks on colder rocks. This led to the cessation of prograde metamorphism and accounts for the ubiquitous association of nappe emplacement and the meta morphic peak. Later deformation (D3/D4) occurred at lower grades (biotite/chlorite). Consideration of nappe translation rates and the likely erosion/cooling rates indicates that nappe movements must have occurred ‘continuously out-of-sequence’ within the Kalak Nappe Complex.

The present work describes the quartz geodes (cauliflower-like) that appear in a specific level of the Late Cretaceous (north of Burgos). Due to their special characteristics, principally anhydrite relicts and spherulitic quartz (length-slow chalcedony), they are considered as pseudomorphs of anhydrite nodules, formed during early diagenesis. At the same level compact chert nodules sporadically appear, presenting a considerable amount of sponge spicules with fibrous texture (length-fast chalcedony). The silicification of the anhydrite nodules took place before total compaction and cementation of the sediment. The source of silica is principally biogenic (sponge spicules). We offer a hypothesis to explain the formation of the anhydrite nodules since there is no link between the depositional environment and the existence in itself of anhydrite nodules. Indirectly it is possible to see the effects of an arid climate, which have not been recorded in the lithologic column here described.

Summary. The available data on radiometric dating of Riphean and Vendian deposits in the European part of the U.S.S.R. enabled us to establish the age of geochronological boundaries. The Riphean lower boundary was adopted as 1650 ± 50 Ma, the Vendian lower boundary as 650 ± 10 Ma, and the Cambrian lower boundary as 590 ± 10 Ma, making the total length of the Riphean about 1000 Ma and that of the Vendian about 60 Ma. This paper suggests a draft of the geochronological scale of the Late Precambrian.

The finger structures described earlier by Brown and later by Butcher, Young & Faithfull involve dissolution of troctolite during crystallization of olivine, followed by crystallization of pyroxene around olivine grains in the fingers. However, the ingestion of troctolite takes the liquid away from pyroxene saturation rather than toward it. The pyroxene field can be encountered metastably, and pyroxene caused to crystallize, by supercooling the olivine-rich liquid against the troctolite. The melt corrosion represented by the fingers, and other field relations, suggest that the mafic layers were emplaced as sills of mafic magma into nearly solid troctolites. Melting at the base of mafic liquid layers was impeded by a bed of olivine crystals releasing light solute upward, causing compositional convention and rapid heat transfer to the top of the layer, where melting demonstrably occurred. Recognition of this process introduces the novel concept of a magmatic heat pump driven by compositional convection. The crystallization path ol–px–pl(–sp) is also found next to xenoliths in the Kiglapait Intrusion where the magma was normally saturated only in ol+pl, directly demonstrating the effect of supercooling on the crystallization sequence.

The graptolite biozonation of the Wenlock Series in the Builth Wells district is reassessed. The graptolite fauna is dominated by relatively few, but variable, species of Monograptus s.s., Pristiograptus and Monoclimacis. These species are mostly long-ranging and are of limited biostratigraphical use. Biozonation is based largely on the relatively rare cyrtograptids. The lower Wenlock Series of the district comprises the widely recognized centrifugus, murchisoni and riccartonensis biozones. The middle to upper Wenlock biostratigraphy differs from that previously recognized in the UK. Above the riccartonensis Biozone, dubius, rigidus and lundgreni biozones are distinguished. Separate flexilis and ellesae biozones are not recognized: Monograptus flexilis appears earlier than, then largely co-exists with, Cyrtograptus rigidus s.l.; while Cyrtograptus ellesae appears later than Cyrtograptus lundgreni. The uppermost Wenlock nassa–ludensis Biozone is sparsely fossiliferous; its subdivision has not proved possible. This revised biostratigraphical scheme for the Wenlock Series of the Builth Wells district suggests that the Sheinwoodian–Homerian boundary, as defined in the Welsh Borderland, might occur within, rather than at the base of, the lundgreni Biozone. However, difficulties in correlation with other Wenlock sequences, particularly overseas, suggest significant biofacies control, with the Wenlock seas of the Builth Wells district appearing to have been periodically inhospitable to graptolites.

The mode of occurrence and petrography of a group of pyroxene- hornblende-granulites (beerbachites), found only in association with serpentinized peridotite, are described. The beerbachites are regarded as contact altered lavas and basic intrusions which formed the lower levels of a thick series of Ordovician volcanics. Peridotite, intruded into the base of the volcanic pile, disrupted and thermally metamosphosed the lavas and intrusions which appear as inclusions in the serpentinized peridotite. The present contacts between serpentinite and adjacent unmetamorphosed rocks are secondary in origin.

Stromatolites of the groups Linella, Tungussia and Tifounkeia in association with thrombolites occur in abundance throughout the whole Lie de Vin Series, the middle part of the Adoudounian Group which consists of Calcaire lnférieur, Lie de Vin Series and Calcaire Supérieur. A Late Precambrian age is suggested for these stromatolites.

The Almacık Mountains in northwestern Turkey expose an upper-amphibolite-facies complex consisting of alternating ultramafic (harzburgitic and websteritic) and mafic (metagabbroic) rock types. In the eastern part of this complex are island arc meta-tholeiites and transitional to calc-alkaline metabasites that are chemically quite similar to those of the Permo-Triassic Çele mafic complex north of Bolu, and this suggests an equivalence. However, much of the section exposes structurally deeper and chemically different mafic and ultramafic rocks, which have no equivalent in the Çele mafic complex, and isotopic dating has suggested that these rocks also formed during the Permian period and underwent Triassic and Jurassic metamorphism. Furthermore, sparse inherited ages, unlike those from İstanbul Zone granitoids, suggest a link with North African-derived Armorican-type basement (and hence the Sakarya Zone), rather than Amazonia-derived Avalonian basement. Alternating mafic and ultramafic rocks suggest structural repetition, supported by the exposure of discrete high-strain zones or poorly exposed shattered rock west of each outcrop of ultramafic rocks. The high grade of metamorphism, and the absence of either extrusive lavas or sheeted dyke rocks, suggests that the Almacık complex was not an ophiolite, but formed instead as subcontinental lower crust and subjacent mantle. Dominantly calc-alkaline geochemistry suggests that it formed the basement to an active continental margin bounding the north side of the Sakarya Continent, with S-dipping subduction of Palaeotethys. The Almacık complex was uplifted as a late result of compression against the southern margin of the İstanbul Zone in the Jurassic period. Lack of coeval high-grade metamorphism in the İstanbul Zone indicates that the latter was overthrust southwards over the Sakarya margin, and that there was therefore a change of subduction polarity in the Triassic period. The evidence further casts doubt on the existence of a Mesozoic Intra-Pontide Ocean in northwestern Turkey and suggests that the latest Permian magmatism, with subsequent Triassic and Jurassic metamorphism, was instead related to the closure of the Palaeotethyan Ocean.

In 1923, H. C. T’an and O. Zdansky collected remains of an ankylosaurid dinosaur in the Late Cretaceous Wangshi Group of the Laiyang region, in eastern Shandong (China). Apart from a few caudal vertebrae, this material, which is kept at the Palaeontological Institution of the University of Uppsala (Sweden), was never described or figured. It includes a well-preserved sacrum with the attached right ilium and part of the presacral rod, caudal vertebrae, a left femur and a dermal scute. This material is referred to an ankylosaurid of the genus Pinacosaurus Gilmore, 1933, on the basis of the widely divergent ilium bearing a strong ventral ridge and of the slenderness of the femur. In the absence of cranial material, a specific attribution is difficult and the Uppsala material is referred to as Pinacosaurus cf. grangeri (P. grangeri being the only generally accepted species of Pinacosaurus). This is the first record of Pinacosaurus outside the Gobi Basin of Mongolia and northwestern China. In the Gobi Basin, Pinacosaurus has been reported only from the Djadokhta Formation or its equivalents, of supposed Campanian age, and it is suggested that at least the part of the Wangshi Group which yielded the Shandong Pinacosaurus may be of roughly the same age as the Djadokhta Formation.

Two new genera and species of Middle Cambrian sphinctozoans, Jawonya gurumal and Wagima galbanyin, are described from the Tindall Limestone of the Daly Basin, Northern Territory, within continental platform successions of the northern Australian craton. They are ambisiphonate sebargasiids, coeval with the island-arc shelf fauna from the Ordian Stage of western New South Wales. Additionally, a new Early Cambrian (Atdabanian equivalent) species, ?Jawonya tiro, displaying some sphinctozoan and some archaeocyathan features, is documented from the Ajax Limestone of the Arrowie Basin, South Australia. It is tentatively regarded as the oldest known sphinctozoan, but raises the possibility of the derivation of sphinctozoans from archaeocyaths. A brief review charts the Early–Middle Palaeozoic history of the sphinctozoans. The use of filling tissue type as a family-level criterion in sphinctozoan classification needs some reappraisal, as some types are of secondary origin.