The time of the onset and the nature of the extension in the Aegean area have been problematic owing to the confusion of neotectonic replacement structures with neotectonic revolutionary structures. This paper concerns two rift systems of different ages and orientations in the Gökova region of southwestern Anatolia. The first system has a northwest—southeast trend with a Middle to Upper Miocene infill, whereas the second system is orientated in an east—west direction and filled with Plio-Quaternary rocks. Structural and palaeomagnetic data indicate that the first system originally had a north—south trend, and then bodily rotated anticlockwise to its present orientation before the end of the Miocene. Both the orientations and the structural patterns of these cross-cutting rift systems suggest that they resulted from two different and successive tectonic régimes. Regional geology suggests that the generative régime of the older system was characterized by north—south compression and related to the palaeotectonic evolution of southwestern Anatolia, whereas that of the younger system is characterized by north-south extension and relates to the neotectonic evolution of this region. This inference contradicts, at least in southwestern Anatolia, some recent claims that the extensional tectonics and the related rift formation in the Aegean region began in the early Miocene, with the alleged demise of the compressional palaeotectonics during the late Oligocene, but is consistent with older views that placed the onset of north—south extension into the later middle Miocene. The formation of the Aegean Sea seems to be the result of these two complicated and contrasting, succesive tectonic regimes that have affected this region since middle Miocene times.

A global Chitinozoan biozonation for the Silurian Period is proposed. Each biozone is an interval range defined by the first occurrence of an index species, selected from well-defined species with a relatively short biostratigraphic range. To be included in the scheme, index species must have been recorded from at least two major Silurian palaeocontinents where usable Chitinozoa assemblages have been studied, that is, Avalonia—Baltica (which had already undergone collision by the Silurian), Laurentia, Gondwana and Southern China. Seventeen biozones are identified with seven in the Llandovery: the fragilis, postrobusta, electa, maennili, alargada, dolioliformis and longicollis biozones; four in the Wenlock: the margaritana, cingulata, pachycephala and lycoperdoides biozones; three in the Ludlow: the elongata, philipi and barrandei biozones; and three in the Přídolí: the kosovensis, elegans and superba biozones. Chronostratigraphic calibration is partly provided by reference to the range of the appropriate Chitinozoa index species in the global stratotype sections and points (GSSP) of the Silurian series, e.g. in Bohemia (Czech Republic) for the Přídolí and the Welsh Borderland in England for the Ludlow and part of the Wenlock. When this information was not available, independent biostratigraphic control was provided by calibration with graptolite biozones or in a few cases, conodont or trilobite biozonal schemes. The index and most characteristic species of each biozone are illustrated and their total stratigraphie range provided.

Mafic dykes from the Øksfjord-Langfjord area were intruded at different stages during the prolonged tectonomagmatic evolution of the Seiland Igneous Province. Field relations, petrography and geochemistry indicate the presence of four dyke generations with alkali basalt composition and one generation of alkaline lamprophyres. The entire dyke suite has geochemical signatures consistent with formation in a within-plate geotectonic environment. Trace elements indicate that the alkali basalt dykes have OIB (ocean island basalt) affinities and we suggest a sublithospheric mantle source. The data support a rift-related origin for the Seiland Igneous Province. Longevity of magmatism in the Seiland Igneous Province (300 m.y.) is difficult to explain within a conventional mantle plume framework. Instead, it is proposed that the intermittent magmatism in the province was predominantly permissive and controlled by lithosphere structure.

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.

In the established European conodont zonation the Paroistodus originalis Zone represents an interval in the upper middle Arenig or middle Lanna/Volkhov Stage. I have so far found it at 14 Swedish localities, represented in my collections by more than 116 000 conodont elements from 79 limestone samples. Presence/absence data together with major frequency shifts among conodont taxa allow the recognition of five successive phases within the P. originalis Zone and the corresponding chron. Phase 1 occurs in the basal part of the zone, where an increase in frequency of Triangulodus brevibasis and P. originalis distinguishes it from immediately subjacent beds. Phase 2 corresponds to the (transgressive) lower middle part of the zone with an influx of Periodon, and Drepanoistodus basiovalis replacing D. forceps. Phase 3 is equivalent to the upper middle part of the zone with generally more than 30% of the zonal denominator and with Microzarkodina parva replacing M. flabellum. Phase 4 is a short (regressive) event where the frequency of Paroistodus is drastically lowered, and phase 5 corresponds to the upper part where Paroistodus again increases. The zone is particularly well represented at Lanna, Province of Närke, in south-central Sweden, where it also seems possible to connect the conodont succession with the standard trilobite zonation. Thus, at Lanna as well as at Finngrundet in the Bothnian Bay, Megistaspis (M.) simon first appears in the basal lower middle part of the P. originalis Zone.

New collections of trilobites have been made from Dinantian rocks in North Devon, distributed among seven genera. Of these, Wagnerispina, Archegonus (Phillibole), Liobole, Aprathia, and probably Lichanocoryphe gen. nov., are primitive phillipsiids belonging to the subfamily Archegoninae. Reasons are given here for the others, Tawstockia and Spatulina, previously considered to be primitive phillipsiids of the subfamily Cystispininae, to belong to the higher phillipsiids, as effaced, blind members respectively of the Linguaphillipsiinae and Cummingellinae. The species of these genera from North Devon discussed here, three of which are new, are either small-eyed or blind, and form an atheloptic assemblage; they occur in hemipelagic sediments of the Codden Hill Chert Group in the Barnstaple district, and the Kersdown Chert Formation in the Bampton district. Ammonoids associated with the trilobites indicate an early Viséan, late Chadian age for the fauna, and the same or similar trilobite species and subspecies occur in the Březina Shales of Moravia, suggesting that they are approximately coeval.

Several recent plate reconstructions of the Iapetus Ocean describe the margins of Baltica as passive until Silurian collision with Laurentia. Yet there is a variety of evidence to suggest that the accretion of the Scandinavian Caledonides began by latest Cambrian—early Ordovician subduction and imbrication of the passive continental margin. One such evidence is provided by eclogites occurring in the Seve Nappe Complex. Previous work by others dated the high-pressure metamorphism at 503±14 Ma (Sm—Nd garnet-omphacite age), and the uplift through the c. 500°C isotherm at 491±8 Ma (40Ar/39 Ar hornblende plateau ages). The protolith dolerites of the eclogites have been correlated with Iapetan rift-facies dolerites of the Baltoscandian margin. If valid, such a correlation implies early Caledonian destruction of the margin, and thus modification of those plate reconstructions which require passive margins around Baltica in latest Cambrian-early Ordovician time. This paper provides a substantially improved basis for the concept that the protoliths of eclogites and their host rocks derived from Baltoscandian rift basins. The chemical similarity between coronitic dolerites and dolerites of the rift basins pertains not only to element concentrations and variations but also to the specific T-MORB signature shared by the two groups. The variation of psammitic and pelitic schists, graphitic schists, calc-silicate gneisses and marbles of the eclogite host rocks equates with sequences of sandstones, siltstones, shales, black shale, quartzite, dolomite and limestones of Baltoscandian palaeobasins.

At the same time, the paper calls attention to the remarkable preservation of structural and metamorphic contrasts within the eclogite-bearing thrust sheets of the Seve Nappe Complex. Such disequilibrium is generally ascribed to the kinetics of localized deformation and fluid infiltration into dry crust. This paper presents evidence that disequilibrium is found also within inferred subducted sedimentary complexes, which are generally assumed to be pervasively flushed by fluids. Preservation of sedimentary, volcanic and magmatic structures and fabrics, and of both undeformed dolerite dykes and eclogitized dykes demonstrates that neither deformation nor high-pressure metamorphism were pervasive.

The distal part of the fused ischia of a prosauropod from the Nam Phong Formation (late Triassic) of Phetchabun Province, in northeastern Thailand, is described. Comparisons with various prosauropods, as well as with an early sauropod, show that the Thai specimen is especially robust. However, the available material is too incomplete to warrant a precise identification. It is the first vertebrate fossil found in the Nam Phong Formation, the oldest known dinosaur from southeast Asia, and the first prosauropod to be reported from that region.