More than sixty years have now elapsed since the publication of the classical monograph of MM. Milne-Edwards and Jules Haime, “Les Polypes Fossiles des Terrains Palæozoïques.” It can only be expected that many of the original descriptions of species in that work have for long been in need of amplification and revision. This applies with added force to the corals of the Carboniferous Limestone, in view of the impetus given to the palæontological study of that formation, by the vigorous revival of zonal work witnessed in the last few years. Those species in most urgent need of revision belong to the lower, or Tournaisian division of the Limestone, since their satisfactory determination affords a basis for evolutionary studies on the succeeding faunas, and an attempt is here made to deal with a few of these forms.

The contact aureole on the northern side of the Ardara granitic pluton is made up of an outer part where contact effects are slight, and an inner part in which a broad zone of andalusite hornfelses is succeeded towards the contact by a narrower zone of sillimanite hornfelses. The textures of the hornfelses indicate that several phases of recrystallization, some of them associated with phases of movement, took place during contact metamorphism. Certain phases can be correlated with particular episodes in the evolution of the pluton itself.

The importance of accurate knowledge concerning the causes of composition zoning in plagioclases lies in the possibility that such zoning may throw light on the magmatic history of the rock of which the zoned felspar is a component. The interpretation of plagioclase zoning has been the subject of much speculation among petrologists, Phemister having recently contributed (1934) a valuable discussion of earlier work, together with certain new suggestions as to the probable causes of the reverse and oscillatory types. My own attention was drawn to oscillatory zoning while studying the Upper Devonian igneous complex of Marysville, Victoria (Hills, 1932, pp. 152, 153), and I found the hypotheses suggested by Phemister and by Harloff (1927) to explain this enlightening. Nevertheless, it seems to me that the real significance of some of the processes postulated by both these workers has not been correctly indicated, and that the mechanism proposed by Phemister to account for oscillatory-normal zoning is not theoretically possible. Since it is important that the physico-chemical basis of such hypotheses be sound, a discussion of Phemister's and Harloff's theories, and certain other possible causes of reverse zoning is given below.

Palaeoenvironmental changes in the upper Middle Miocene Central Paratethys were reconstructed by using qualitative and quantitative palaeontological analyses of foraminifera and ostracods, coupled with trace elemental (Mg/Ca) and stable isotope (δ18O and δ13C) analyses of their carbonate skeletons and of gastropod shells. Mean annual air temperatures were estimated using the oxygen isotope composition of contemporaneous rodent teeth. The studied aquatic fossils come from two boreholes in the Zsámbék Basin (northern central Hungary), while the terrestrial ones are from localities in NE Hungary and E Romania. In the studied Sarmatian successions, three zones could be distinguished, based on palaeontological and geochemical results. At the Badenian/Sarmatian boundary, faunal diversity decreased markedly. In the lower zone a transgressive event culminated in a seawater incursion into the semi-open basin system of the Central Paratethys. Stable bottom-water temperature (~15 °C) and variable salinities (20–32 ‰) are estimated for the Early Sarmatian Sea. The faunal changes (notably a strong reduction in biodiversity) occurring at the boundary between the lower and the middle zone can be explained by a sea-level highstand with dysoxic conditions. A relative sea-level fall is documented at the end of this middle zone. After a short regressive event, a marine connection between the Paratethys and the Mediterranean was established at the beginning of the upper zone. This is indicated by an increased microfaunal diversity and the re-appearance of marine Badenian ostracods and foraminifera, which are completely absent from the older Sarmatian series. During the upper zone, the temperatures and salinities are estimated to have fluctuated from 15 °C to 21 °C and from 15 ‰ to 43 ‰, respectively.

Detailed petrographic and geochemical studies conducted on zircons from the Lys-Caillaouas pluton reveal their igneous and metamorphic affinities. The igneous zircons constrain the emplacement of the pluton to 300±2 Ma. By contrast, the metamorphic zircons yield an older age of 307±3 Ma, which probably dates the thermal peak of the HT/LP Variscan metamorphism. Therefore, a short time lag of c. 7 Ma emerges between the metamorphic climax and emplacement of the pluton in the Axial Zone (Pyrenees).

The North-East Greenland eclogite province is divided into a western, central and eastern block by the sinistral Storstrømmen shear zone in the west and the dextral Germania Land deformation zone in the east. A family of steep, NNW-striking dextral mylonite zones in the Danmarkshavn area are geometrically and kinematically similar to the ductile Germania Land deformation zone, located 25 km to the east. Amphibolite facies deformation at Danmarkshavn is characterized by boudinage of eclogite bodies within quartzofeldspathic host gneisses, pegmatite emplacement into the boudin necks and subsequent deformation of pegmatites parallel to gneissosity, a widespread component of dextral shear within the gneisses, and localization of strain into 10–50 m thick dextral mylonite zones. The gneisses and concordant mylonite zones are cut by a swarm of weakly to undeformed, steeply dipping, E–W-striking pegmatitic dykes. Oscillatory-zoned zircon cores from two boudin neck pegmatites give weighted mean 206Pb/238U sensitive, high mass resolution ion microprobe (SHRIMP) ages of 376 ± 5 Ma and 343 ± 7 Ma. Cathodoluminescence images of these zircons reveal complex additional rims, with ages from ranging from c. 360 to 320 Ma. Oscillatory-zoned, prismatic zircons from two late, cross-cutting pegmatites yield weighted mean 206Pb/238U SHRIMP ages of 343 ± 5 Ma and 332 ± 3 Ma. Zircons from the boudin neck pegmatites record a prolonged growth history, marked by fluid influx, during amphibolite facies metamorphism beginning at c. 375 Ma. The cross-cutting pegmatites show that dextral deformation in the gneisses and ductile mylonite zones had stopped by c. 340 Ma. Ultrahigh-pressure metamorphism in the eastern block at 360 Ma requires that the Greenland Caledonides were in an overall contractional plate tectonic regime. This, combined with 20% steep amphibolite facies lineations in the eclogites, gneisses and mylonites suggests that dextral transpression may have been responsible for a first stage of eclogite exhumation between 370 and 340 Ma.

Two internal discontinuities are described from the Tertiary, Shiant Isles sill (northwest Scotland). The lower discontinuity separates picrite from overlying picrodolerite and the recently discovered upper discontinuity separates picrite from underlying crinanite. The sill is thus divided into an inner, strongly differentiated, picrodolerite–crinanite unit and outer picritic units. The lower discontinuity is slightly transgressive with respect to the picrite. The discontinuities are interpreted as the contacts between an earlier-intruded picritic sill (about 30 m thick) and a slightly later-intruded, much thicker, crinanitic sill. The Shiant Isles main sill is therefore a multiple intrusion.

Geological work and drilling in the Western Uganda Rift since 1939 points wholly to the formation of this feature by gradual sinking of the floor. No evidence of compression has been obtained.

Non-marine redbeds (Permian and Triassic) in the island of Mallorca consist of a 0.4 km-thick alluvial succession that passes upwards into siliciclastic–carbonate coastal deposits. Tectonics and sealevel changes have been the main influences in their evolution. Low in this succession (the ‘Areniscas y lutitas de Port des Canonge’ unit) sandstone sheets with lateral accretion surfaces (macroscale inclined strata) and mudstones with frequent exposure structures are interpreted as the products of a sinuous alluvial system and floodplain. Climatic fluctuations are considered to be responsible for some significant up-section changes in the evolution of the alluvial deposits. Low-angle or horizontally stratified sandy units, interpreted as the result of flash floods, alternate upwards with point-bar deposits in the ‘Areniscas de Asá’. The hydrological response to minor climatic changes was evidently nearly instantaneous due to the lack of significant vegetation cover.

During accumulation of mudstones and sandstones of the overlying ‘Lutitas y Areniscas de Son Serralta’ unit, the interpreted environment of deposition changed from a distal braidplain, mainly constructed by superposition of sandy bedforms with straight or linguoid crestlines in low sinuosity river channels, into a coastal plain with evidence of both continental and marine influences. The overlying carbonate platform (Muschelkalk) marks the development of a more homogeneous marine environment resulting from the Tethyan transgressive event that affected the whole peri-Mediterranean realm during the Anisian (middle Triassic).

A new Late Cambrian trilobite–brachiopod fauna from the Kurchavinskaya Formation, Severnaya Zemlya, northern Siberia, allows correlation of the Ketyi Horizon of the NW Siberian succession with the praecursor Zone of the Baltic olenid zonation. The presence on Severnaya Zemlya of the typically Siberian trilobite Kujandaspis ketiensis indicates that even if Severnaya Zemlya lay on a separate plate, whether Kara or Arctida as postulated by other authors, then it was still probably not far from Siberia. However, the associated brachiopods are partly endemic to Severnaya Zemlya, thus giving some support to the independent palaeomagnetic evidence for their origin on a plate separate from Siberia.

Zoophycos-group burrows are prevalent elements of the post-Cambrian trace fossil record. Here we report the oldest specimens of Zoophycos from Lower Cambrian strata of the Lower Member Wood Canyon Formation in southeastern California. In addition to these being the oldest examples of this well-known trace fossil, the discovery of these specimens also reveals the presence of deposit feeding considerably earlier than has been suggested for the advent of this feeding style. This type of activity may have had a significant impact on sediment mixing during the Precambrian–Cambrian transition, though the rarity and shallow tier position of these specimens suggests otherwise.

It has recently been reaffirmed, on the basis of evidence derived from published maps, that in the Moine schists the south-easterly plunging lineation appears to increase in intensity as the Moine thrust area is approached. This statement is not in accordance with facts observable in the field and is a false premise on which to base the conclusion that thrusting and lineation are related. A further fact of vital significance in relation to such a conclusion is the widespread development of a similar lineation, plunging south-easterly and likewise expressive of a girdle fabric, in unmoved Lewisian rocks of the foreland.

A forecast of an earthquake should identify the first stages of earthquake development: nucleation and stick-slip. We show that a forecast cannot be achieved by seismic measurements due to their high attenuation, but can be obtained by judicial filtering of electromagnetic radiation. Results show that electromagnetic radiation emitted from fractures (FEMR) during the early stages of an earthquake is less attenuated than seismic measurements due to the high frequencies involved, but could be cluttered by external noise. Based on our previous studies, an analysis of FEMR constructed on a profile of individual pulses can remove part of the clatter.

(I) In each of the areas examined the transition zone between the Hecla Hoek rocks of Eastern New Friesland and the more highly metamorphosed belt has been observed and the evidence points to a gradual increase in metamorphism westwards with the same general series of rocks involved. The rocks have been isoclinally folded and repetition occurs more especially on the east flank of the intensely metamorphosed zone. Usually only the Lower Murchison Bay Formation appears in the more highly folded belt, but it may well be that in the Stubendorff Mountains other rocks are also included.

In the northern area, west of Treurenberg Bay, Blomstrand's recognition of a central core of granitic gneiss giving way on both sides to less highly metamorphosed types still stands as the most important contribution to the interpretation of the structure. Recent examination has revealed that the sequence of events has been a folding of the Lower Murchison Bay Formation followed shortly by igneous intrusion and metamorphism of the whole.

In the Gullfaxe area isoclinally folded rocks of the Lower Murchison Bay Formation are associated with a quartz-felspargneiss. We have not been able to decide what this rock was originally. It may be either a metamorphosed igneous rock or an altered arkose. It appears to be concordant with the adjacent altered sedimentaries, but may be igneous material in some way related to the large granitic intrusion which lies farther west in this latitude.

In the Lomme Bay area Odell observed the transition zone.

(2) In the less altered zone to the east of the Duner Glacier we have been able to recognize the members of the Murchison Bay Formation as defined by Kulling, and the correlation is set out in Table I. The least satisfactory identification is of the Salodd and Raudstup Series. According to Kulling these Series have different characteristics in the Lomme Bay area from those which they show in North-East Land, and it may be that throughout New Friesland they attain neidier the thickness nor the distinctive character which is theirs in the type area. The presence of the other members of the Murchison Bay Formation and of the remarkable Sveanor Formation is well established.

Jabal Dumbeir is a nepheline syenite-carbonatite complex of Cambrian age (550 ± 87 Ma). The earliest igneous event of the complex was the intrusion of a phlogopite-sodalite nepheline syenite (ditroite) which was derived from the partial melting of the upper mantle. K, CO2 and F-rich volatiles metasomatise both the ditroite and the gneissic country rock which results in an orthoclase-rich undersaturated syenite (orthoclasite). Carbonatitic breccias and sovite dykes were subsequently emplaced carrying high levels of F, REE, Y and Th with extremely high LREE/HREE ratios (CeN/YbN = 64 ± 8). Such carbonatiticmagmas may be derived by partial melting of an LREE-enriched upper mantle. Hydrothermal emplacement of fluorite-quartz veins represent the final phase of igneous activity and these carry high levels of REE, Y, Th and U. Their emplacement was strongly controlled by a system of NNE strike-slip faults which have been reactivated in recent times.

The Barents Sea region of Arctic Norway preserves a thick succession of marine and deltaic Triassic strata that yield an abundant and diverse association of terrestrial and marine palynomorphs. Despite being the principal means for dating and correlation across this vast region, the Upper Triassic palynozonal resolution has remained relatively low. This is problematic due to the thickness of the Upper Triassic Series and since this corresponds to the longest of the three Triassic epochs. This paper presents a refined Middle–Upper Triassic palynozonation for the region, based on a detailed investigation of multiple localities ranging from the Svalbard Archipelago to the southern Barents Sea. The zonation comprises eleven spore-pollen zones: the Carnisporites spiniger, Triadispora obscura and Protodiploxypinus decus zones (Anisian), the Echinitosporites iliacoides Zone (Ladinian), the Semiretisporis hochulii, Podosporites vigraniae, Leschikisporis aduncus, and Protodiploxypinus spp. zones (Carnian), the Classopollis torosus, and Quadraeculina anellaeformis zones (Norian), and the Ricciisporites spp. Zone (Rhaetian). Additionally, two new dinoflagellate cyst zones are defined: the Rhaetogonyaulax arctica (upper Carnian – lower Norian) and Rhaetogonyaulax rhaetica (lower Norian) zones. Three new age-significant palynomorph taxa are described: Kyrtomisporis moerki sp. nov., Podosporites vigraniae sp. nov. and Semiretisporis hochulii sp. nov. The revised palynozonation is compared with previous palynozonal schemes for the Greater Barents Sea region, and its relationship to Triassic palaeoclimate, palaeoenvironments and sequence stratigraphy is discussed.

Microstructural, finite strain and vorticity analyses of quartz-rich mylonites were used in order to investigate kinematics of rock flow and deformation temperature in the Sirjan thrust sheet exposed in a structural window within the Sanandaj–Sirjan High Pressure – Low Temperature (HP–LT) metamorphic belt that forms part of the hinterland of the Zagros orogenic belt of Iran. A dominant top-to-the-SW sense of shear in the study area is indicated by several shear sense indicators such as asymmetric boudins, rotated porphyroclasts, mica fish and S/C fabrics. Quantitative analyses reveal approximately plane strain deformation conditions with Rxz values ranging from 2.5 to 4.3 and increasing towards the Sirjan thrust. Opening angles of quartz c-axis fabrics and recrystallization regimes suggest deformation temperatures vary from 430 to 625 ± 50°C in the hanging wall rocks. Oblique grain shape and quartz c-axis fabrics were used to estimate the degree of non-coaxiality during deformation. The obtained vorticity profile indicates a down-section increase in kinematic vorticity number (Wm) from 0.6 to 0.89. This range of vorticity numbers confirms contributions of both simple (41–68 %) and pure shear (32–59 %) deformation components. The structural characteristics of the study area ultimately were controlled by oblique motion of the Afro-Arabian plate relative to the Iranian plate.

The Velasco orbicular granitoid is a small (65 × 15 m), irregularly-shaped body that crops out within the Huaco granite, central Sierra de Velasco, NW Argentina. It consists of ellipsoid-shaped orbicules of 3 to 15 cm length immersed in an aplitic to pegmatitic matrix. The orbicules are formed by a core made up of a K-feldspar megacryst, partially to totally replaced by plagioclase, an inner shell of radial and equant plagioclase crystals, a layer of tangentially oriented biotite laths, and an outer shell of plumose plagioclase crystals, containing diffuse rings of tangentially oriented biotite. The orbicular granitoid formed in situ in a pocket of evolved and volatile-rich melt segregated from the surrounding partially crystallized Huaco granite, possibly via a filter pressing mechanism. The segregated melt entrained relatively few K-feldspar megacrysts into the pocket, leaving behind a concentration of megacrysts around the pocket. High water concentration caused effective superheating of the melt and destruction of nuclei, with only the large megacrysts surviving as solids. Sudden water-pressure loss and exsolution of the volatile phase, perhaps related to a volcanic eruption or fracturing of the surrounding granite, caused rapid undercooling of the melt. The orbicules grew in the undercooled melt by heterogeneous nucleation on the megacrysts, which acted as nucleation seeds, and crystallization of reversely zoned radial plagioclase and sporadic crystallization of tangential biotite rings according to fluctuations in its saturation. Orbicular growth gave way to crystallization of the equiaxial inter-orbicular matrix in two stages, when sufficient polymerization of the melt was attained. The time scale of formation of the orbicular granitoid was fast, possibly a matter of a few weeks or months.

The mylonitic character of the peridotites of St. Paul's Rocks on the Mid-Atlantic Ridge was reported in a contribution by the writer (Tilley, 1947), these ultrabasics then being referred to as dunite or peridotite mylonites. The available chemical analytical data were assembled in that paper and a new analysis provided of a two-pyroxene representative. The type carrying porphyroclastic amphibole was represented by an analysis by Washington (1930) but it was shown that this analysis erred in its alkali determination, and that the reported occurrence of jadeite could not be confirmed.