The base of the Lower Leintwardine Beds (Silurian-Ludlow Series) in the shelf sequences of the Welsh Borderland is marked by a widespread development of shelly conglomeratic limestone beds. Borings into some intraclasts indicate that they were hardgrounds. The early lithification, sometimes in situ, of both sand-grade and mud-grade carbonates is demonstrated by the conglomerates. Some compound intraclasts (‘hiatus concretions’) indicate a complex history of deposition, scouring and lithification. Boring of clasts which have not been further eroded is inferred to have taken place locally. The borings are of the narrow, single entrance form referable to Trypanites. The distribution of the conglomerates relates closely to Leintwardinian palaeogeography. Repeated hardground formation in sequences of inner shelf areas reflects episodic deposition alternating with periods of omission and erosion. There is evidence throughout the shelf of a break in sedimentation with hardground formation at the end of Bringewoodian times. The nature of the conglomerates suggests that they formed in shallow water conditions; there is no lithological indication of sub-aerial exposure. The absence of the Aymestry Limestone in the SE shelf is more probably due to its non-deposition or lateral lithological change to muddier beds with a different faunal assemblage than to its subsequent removal by erosion.

New ammonite finds indicate that the sea transgressed over the crystalline basement of Milne Land, East Greenland, in Boreal Bathonian time and not in Middle Oxfordian as previously thought. A coral (Enallocoenia callomoni Beauvais) occurring in the transgressive Upper Bathonian deposits is the first hermatypic coral known from the Boreal Middle Jurassic. The unusually complete Boreal Upper Callovian–Oxfordian–Kimmeridgian ammonite succession is described; the faunas include remarkable occurrences of submediterranean genera (Hibolithes, Pachypictonia, Streblites). Finally, the sedimentary and tectonic evolution of Milne Land and adjacent areas in Jurassic time is outlined. It is shown that the area was characterized by gentle block-faulting.

Cumulative curves of grain-size against frequency often show segmented shapes which have been interpreted as the result of combination of normally distributed populations. The origin of the segments is explored by the examination of two classes of models, truncation and mixing. Similar curves may be generated by a variety of models. The segments rarely reflect precisely the original populations. Simulation of the tri-segmented curves commonly ascribed to combinations of suspension, saltation and traction populations shows that the characteristics of the contributing populations are not consistent with these three modes of transportation.

Sheet-like and channel-filling conglomerates and pebbly biomicrudites occur within a sequence of cross-stratified shallow-water bioclastic limestones, the Forest Hill Formation of Late Oligocene to Early Miocene age. The largest channel, 50 m wide, 9 m deep, and at least 1.2 km long, is infilled with four separate conglomerate units of pebble- to boulder-sized limestone lithoclasts in a sparse muddy matrix (biomicrudite). Both the conglomerates and associated pebbly biomicrudites possess features characteristic of high concentration mass flows - both of laminar flow (preferred clast orientation, inverse grading or massive bedding) and of turbulent flow (normal coarse-tail or distribution grading and stratification). Clast imbrication (a- or b-axes) is suggestive of gradual deposition. Some flows travelled far enough to allow both vertical and horizontal differentiation of the coarse sediment. Facies models which have been proposed for conglomerates of deep water (turbidite) association can also be applied to the small-scale neritic conglomerates. Formation and remobilisation of such coarse grained facies in a shelf setting is attributed to eustatic sea-level changes and/or to local tectonism.

The Ordovician Fauna from the Contaya Formation from the lowlands of eastern Peru is fully described for the first time. The fauna is restricted and consists essentially of brachiopods, trilobites and Graptolites and three new species, the brachiopod Tissintia simplex, and the trilobites Anebolithus tafuri and Porterfieldia contayaensis are described. The fauna is shown to have close affinities with those of central Europe and North Africa.

The Soviet Arctic extends 6700 km from the border with Norway, on the west, to the border with the United States, on the east. The region contains the largest unexplored shelf area on earth – approximately 3917000 km2. Of the several onshore petroleum-bearing basins, at least two extend into the offshore – the Timano-Pechora basin, which passes beneath the Barents Sea, and the West Siberian basin, which includes much of the Kara Sea. The Laptev and East Siberian Seas seem to be underlain by separate offshore basins, possibly unrelated to any onshore. The Chukchi Sea is geologically a part of the Alaskan North Slope. The Vilyuy basin, along the Vilyuy and Lena Rivers, does not extend offshore. Only small basins are present along the Pacific shore; of these, two have petroleum potential – the Khatyrka basin which passes eastwards into the Navarin basin of the Bering Sea, and the Anadyr' basin which joins the St Lawrence basin. Peripheral to the Arctic, but of great importance relative to several Canadian Arctic basins, is the Irkutsk amphitheatre in which the main hydrocarbon accumulations are Proterozoic.

Of the three largest onshore basins, the West Siberian is the greatest, with major production from Lower and Middle Cretaceous, and smaller production from Upper Jurassic and Upper Palaeozoic rocks. The major production from the Timano-Pechora basin is from the Middle Devonian and Upper Carboniferous–Lower Permian; minor production is from the Silurian, Lower Devonian, Upper Devonian, Lower Carboniferous, Upper Permian and Triassic. Production in the Vilyuy basin – all of it gas – is from Lower and Middle Jurassic, Triassic and Permian. Although non-commercial, known potential production from the Nordvik area is from Triassic and Permian sandstones; that from the Khatyrka basin is Oligocene and that from the Anadyr' basin is Miocene. The potential of the Soviet Arctic is huge, with major oil reserves and the largest known gas reserves on the earth.

In the last few years the problem of the lower boundary of the Cambrian has been dealt with in dozens of works which considered not only the history of the question but all the current material available. It is a subject discussed at many national and international symposia. Although great progress has been achieved in drawing together the points of view on the position of the boundary (compare the results of the symposia held in Paris in 1958 with that in 1974), the range of different opinions still remains wide, particularly with regard to the zonal scales (for example, in Siberia, from the base of the Nemakit–Daldyn horizon up to the base of the beds with Fallotaspis). First, therefore, we give consideration to those questions which often constitute a stumbling block. It seems necessary to make a reservation that some of the difficulties arising may undoubtedly be referred to as purely psychological.

The stratigraphy and palaeobotany of new in situ exposures of interglacial deposits at Swanton Morley, Norfolk are described. These organic sediments, which probably accumulated in a river back channel, are shown to cover pollen zones Ib to IIb of the Ipswichian interglacial. Macroscopic plant fossils include a new record for Trapa natans from subzone Ip IIb. Vertebrate remains from the new excavations, and from previous finds, have been pollen-dated. The Ip IIa fauna, the first recorded from this subzone, includes Emys orbicularis, small mammals including Microtus oeconomus, and some large mammals. Hippopotamus amphibies is recorded from early zone Ip III. Of particular interest are hazelnuts gnawed by Apodemus, and large mammal bones damaged by Crocuta.

Many volcanic ash layers preserved in deep-sea sediments are the products of large magnitude ignimbrite eruptions. The characteristics of such co-ignimbrite ash-fall deposits are illustrated by two layers from the Eastern Mediterranean: the Minoan ash, Santorini, and the Campanian ash, Italy. These layers are divisible into a coarse lower unit and a fine upper unit in proximal cores. Both layers also show striking bimodal grain size distributions in more distal cores. The coarser mode decreases in median diameter with distance from source whereas the finer mode shows no lateral variation. These features are interpreted in terms of a model for ignimbrite formation by eruption column collapse. Comparable volumes of ignimbrite and associated air-fall ejecta are produced.

The mineral assemblages in calc-silicates collected from Ballindalloch and Bridge of Avon suggest that the grade of metamorphism is lower than in the areas to the E and W. Mild post-metamorphic warping may be responsible for the production of an apparent ‘thermal anticline’ in the Monadhliath Mountains and the complementary ‘thermal syncline’ in Lower Strathspey.

Boreholes drilled at Sandnes, SW Norway penetrated Quaternary (Weichselian) marine interstadial sediments which contained ostracods. The ostracods, which are analysed and discussed, were found to be indicative of cool, probably sub-arctic, shallow-water conditions. Some evidence of faunal mixing is attributed to the effects of glacial meltwater input into a shallow marine environment.

The field occurrence and the known immiscibility between silicate and carbonate melts suggest the Jombo alkaline intrusion and Mrima carbonatite intrusion have come from the same magmatic source. However, only the ijolite series apparently originated from a magma body at Jombo hill intrusion, while the feldspathoidal syenite series appears to have resulted from metasomatic alteration of the country rock-sandstone. The K/Rb ratios seem to indicate a mantle origin for the ijolites and a crustal one for the feldspathoidal syenites. The feldspathoidal syenite series were presumably formed by alkali metasomatism, resulting from magmatic fluid infiltration through intergranular movement. It is suggested that the partitioning of K and Na components in the metasomatizing fluid and solid feldspar phases at different temperatures, was the cause of two rock types – albite nepheline syenite and orthoclase nepheline syenite.

A brief review of Becke's (1908) replacement and Schwantke's (1909) exsolution models for myrmekite genesis and further consideration of the morphology and spatial distribution of myrmekite as outlined by Phillips (1974) lead to the conclusion that both hypotheses have a place in explaining the origin of myrmekite. The Schwantke model is generallybest applied, for example, to high-level undeformed massive granitoids and the Becke model to deformed metamorphic rocks. The latter hypothesis and a third model involving interaction between exsolution and replacement (Ashworth, 1972) may be used especially to explain the association of muscovite and myrmekite in rocks whose mineral assemblages have undergone retrograde modification, involving either redistribution of Na, Ca and K by local metasomatic reactions among the mineral grains, or metasomatic change of bulk rock composition.

A set of sub-vertical curving fissures in a Pennine-derived lodgement till of Wolstonian age is described from Church Wilne near Derby. The fissures are at least 5 m long and curved (radius of curvature c. 3 m) in both vertical and horizontal planes, the concavity facing SE in the direction of regional ice movement. The origin of the structures is considered in the light of a review of modes of formation of structural discontinuities in till. Origins due to stress relief following excavation, desiccation, frost action, direct ice push, ice-core meltout, compaction of the substrate and shear failure are rejected. It is proposed that the fissures were produced by point loading of a frozen till surface by englacial (basal) boulders which provided periodically high compressive stresses and induced tensional failure. Analogous fissures occur in a Devensian lodgement till in the Wirral peninsula in Cheshire. It is concluded that curved fissure sets are localized features of lodgement tills but that they may be quite widely distributed.

Sand waves are such comparatively immobile transverse bedforms because they occur in tide-induced oscillatory bottom boundary layers typified by a steady velocity-component that generally is small compared to the amplitude of the periodic part. Consequently, the net bed-material transport rates, responsible for the long-term translation of the sand waves, typically are very small compared with the larger of the instantaneous rates. Sand waves should, therefore, be marked internally by series of erosional or, under restricted circumstances, non-depositional master bedding surfaces, each such surface, together with an associated comparatively thin sediment increment, being attributable to one sand-driving tide. Studies of modern sand waves, and investigations in the stratigraphic record, lend support to this conclusion. A further consequence of the regime of intense reworking under which sand waves exist is that their component grains should be in all ways more mature, other things being equal, than particles transported the same net distance by rivers.

Recent resurgence of interest in the Mesozoic rocks of SW and southern Cyprus necessitates redefinition of the Mesozoic sedimentary and igneous rocks in line with modern stratigraphical convention. Two fundamentally different rocks associations are present, the Troodos Complex, not redefined, a portion of late Cretaceous oceanic crust, and the Mamonia Complex, the tectonically dismembered remnants of a Mesozoic continental margin. Based on earlier work, the Mamonia Complex is divided into two groups, each subdivided into a number of subsidiary formations and members. The Ayios Photios Group is wholly sedimentary, and records the evolution of a late Triassic to Cretaceous inactive continental margin. The Dhiarizos Group represents Triassic alkalic volcanism and sedimentation adjacent to a continental margin. Several other formations not included in the two groups comprise sedimentary mélange and metamorphic rocks. The Troodos Complex possesses an in situ late Cretaceous sedimentary cover which includes two formations of ferromanganiferous pelagic sediments, radiolarites and volcaniclastic sandstones. The overlying Cainozoic calcareous units are not redefined here.

Central Isla Hoste lies towards the Pacific side of a Mesozoic back-arc basin in southern Chile, behind a magmatic arc represented by the Patagonian batholith. The volcaniclastic sediments on Isla Hoste were derived from the magmatic arc and deposited in the back-arc basin by turbidity currents. These sediments may, in part, overlie mafic volcanic and intrusive rocks. Geochemical and lithologic data are used to suggest an ocean-floor origin for these mafic igneous rocks on central Isla Hoste. The sedimentary and mafic igneous rocks were deformed and uplifted during the middle Cretaceous Andean orogeny. However, the nature of the crust underlying most of the sedimentary rocks in the back-arc basin and the style of deformation in most of this basement are unknown. Therefore the role, if any, of subduction within the back-arc basin during the middle Cretaceous ‘closure’ of this basin is not certain. Post-kinematic intrusions within the back-arc basin are common. These intrusions will confuse attempts to determine by geophysical means the nature of the pre-kinematic basement of the back-arc basin and attempts to outline the present extent of the basin in offshore regions.

In the Geological Magazine115 (5), 1978, Lane & Thomas proposed the name Rhax for a scutellid of probable late Llandovery from Queensland, Australia.

Two new camerate crinoids from the Henryhouse (Ludlow) of Oklahoma are evolutionarily convergent on monocyclic inadunates. The prokopicrinid Nanicrinus (new) has a calyx consisting only of three basals (small basal in EA interrary) and five radials. The anal opening is bordered by two radials. Praedicticrinus (new) is a hirneacrinid with anal X as the sole interradial plate participating in the calyx and small basal located in DE interray. Assignment to the Camerata is based largely on presumed phylogenetic relationships. The similar-appearing Permian genera Plesiocrinus, Eutelecrinus, Metaeutelecrinus (new) and Paraeutelecrinus (new) are probable prokopicrinid homeomorphs derived from platycrinitid ancestors. They are assigned to the new family Eutelecrinidae. Adaptation of the definition of homeomorphy utilized by Chauff & Klapper (1978) is advocated for supposed paleontologic cases.

New work on the sedimentology and palaeontology of the classic area of the ‘basinal’ facies of the Carboniferous Limestone requires that a formal lithostratigraphic framework be established to rationalize the existing system of local rock units and regional lithofaunal ‘groups’ and ‘series’. Five formations, based on the existing ’groups‘ in the Clitheroe area, are defined for the whole Craven Basin outcrop. They are, from the base, the Chatburn Limestone Formation, the Clitheroe Limestone Formation (which includes the ’reef-knolls’ of the Clitheroe area), the Worston Shale Formation, the Pendleside Limestone Formation (to include the knolls of the Craven reef belt) and the Bowland Shale Formation. The chronostratigraphy, in terms of the six British Dinantian Stages, and a provisional micropalaeontological biostratigraphy are outlined.