Contact relations and petrography of the volcanic breccia known as the Stac Fada Member, near Stoer, show that it is not a simple sediment-gravity flow, but was generated lower in the sedimentary succession by phreatomagmatic activity and rose to the surface as buoyant peperitic slurry. A previously undescribed part of the member, 9 m below the intrusive base of the main ‘flow’, has an intrusive top. Vesicle trains within the breccia matrix suggest that the slurry was boiling at a temperature of at least 160°C.

Two Ordovician graptolite assemblages are recognised and described for the first time in the allochthonous siliceous assemblage or succession forming the Guayacan Group of central Sonora in northwestern Mexico. A Middle Ordovician assemblage referable to the Nemagraptus gracilis-Climacograptus wilsoni zonal interval occurs in the upper siliceous shale of unit 1 of the Guayacan Group and an Upper Ordovician assemblage representative of the Dicellograptus ornatus Zone of the Pacific faunal province has been collected from shaly partings in the bedded radiolarian chert constituting unit 2. The stratigraphical make-up of the siliceous assemblage bears a striking similarity to the better known—and correlative—Lower Palaeozoic siliceous succession of central and northern Nevada, giving credence to the hypothesis that the Palaeozoic siliceous assemblage in northwestern Mexico was originally the extension of the Nevadan assemblage into California, which has been transposed to its present position along a left-lateral megashear of the magnitude of at least 1000 km.

A review of the proximal development of the spinose species remaining in the form genus Climacograptus Hall has led to the proposal to restrict the genus to Climacograptus bicornis (Hall), its type species, and to two other septate species of early Middle Ordovician age (Llandeilo-early Caradoc) with a primitive type of proximal-end development. The genus Euclimacograptus, with Climacograptus hastatus T. S. Hall as the type species, is proposed for spinose Upper Ordovician climacograptids with an advanced proximal-end development. The genus Ensigraptus, with Climacograptus caudatus Lapworth as the type species, is also proposed for species homeomorphic with those included in Normalograptus Legrand but with a less advanced proximal-end development. Five species are described.

The stratigraphy, classification and correlation of the marine strata in the Dinantian (Lower Carboniferous) succession of central Scotland are discussed. Correlations of eight principal marine bands in the upper part of the sequence are proposed and four Hosie limestones are recognised in Fife. The marine macrofossils are listed and their vertical and lateral distribution discussed. Biofacies maps of the main marine faunas are presented, which indicate an eastern origin for the marine transgressions and suggest the existence of a river entering the region to the N of Glasgow. Observations are made on the range of host-sediments in which the most commonly occurring genera are found and palaeoecological interpretations are made concerning the main components of the faunas. Some evidence is given to suggest that some elements of the faunas migrated into the region from the E. The palaeogeography is discussed and a correlation is outlined between epifaunal forms at some horizons and areas of less subsidence in the general regional pattern of differential subsidence.

The Lower Carboniferous of northern Britain is dominated by non-marine sequences which yield fish and crustacean faunas. These are rarely preserved and occur in thin layers. The sedimentology of twelve shrimp-bearing localities is described, in most cases for the first time, to shed light upon the habitats occupied by eumalacostracan crustaceans during their early Carboniferous adaptive radiation. Nearly all these sequences were deposited in coastal delta-plain settings or in interdistributary bays, environments of transitional salinity. The Gullane shrimp bed, however, was laid down in a thermally stratified non-marine lake, and its sole crustacean representative, Tealliocaris, seems to have been generally confined to waters of low salinity. None of the shrimp-beds was deposited in a fully marine environment, though most show evidence of at least some marine influence. Crustacean diversity increases with salinity, and the lack of shrimps in fully marine sediments is largely due to taphonomic factors rather than an environmental control.

The geological theory of the evolution of the material environment and the biological theory of the evolution of organisms by natural selection are usually treated separately. This paper presents a new evolutionary theory, in which the evolution of the organisms, and the evolution of their material environment, are seen to be so closely coupled as to form a single, indivisible, process. This combined evolutionary system can be taken to be a domain with emergent properties unexpected from a simple addition of its component parts, rather like the eighteenth-century scientific view of the Earth as a super-organism. In homage to James Hutton, who lectured before the Royal Society of Edinburgh about the Earth as a super-organism and on the physiology of the Earth, the new topic is called geophysiology.

The difference between the geophysiological view of the Earth, where the environment and the organisms are tightly coupled, and the co-evolutionary, or biogeochemical view, where the coupling is loose leaving organisms and their environment to evolve more or less separately, is discussed. The paper includes numerical models to illustrate how a close-coupled evolutionary system could have self regulation, homeostasis, as an automatic and emergent property. The models will be compared with the real world past and present and their predictions examined.

Silurian sediments up to 2500 m thick are exposed in the Pentland Hills, SW of Edinburgh. These sediments, the North Esk Group, are here sub-divided into five well-defined formations: the Reservoir Formation, Deerhope Formation, Cock Rig Formation, Wether Law Linn Formation and Henshaw Formation. The Wether Law Linn Formation is further sub-divided into three members. Based on limited palaeontological evidence, the sediments appear to be late Llandovery (crenulata Biozone) to Wenlock in age. The Silurian sediments represent a regressive sequence, passing from offshore submarine-fan turbidite facies, through shallow marine sediments, with an abundant flora and fauna, possibly a barrier complex, to terrestrial red beds of Old Red Sandstone facies. Changing faunal associations in the shallow marine sediments reflect the availability of different substrates. The regression occurred on the southern margin of the Midland Valley graben.

There is a general consensus that the global chemistry of ocean water has not changed markedly during the Phanerozoic. Nevertheless, significant changes have occurred in the geochemical cycles of some elements and patterns of change have been reconstructed, in various forms, through consideration of the isotope ratios 13C/12C, 34S/32S, 87Sr/86Sr and 143Nd/144Nd. There have also been attempts to constrain variations in the isotopic composition of sea water itself through measurements of D/H and 18O/16O, the latter both directly and indirectly. Dissolved constituents in seawater display secular changes in isotopic composition as a consequence of quite different driving mechanisms. δ13C and δ34S variations are broadly correlated and linked by carbon and sulphur exogenic cycle interaction through redox reactions (the “free oxygen cycle”). The 87Sr/86Sr trend is determined by the balance among different Sr inputs to the oceanic pool, which vary in their isotopic composition (limestones, old granitic material and young basaltic material). Neodymium isotope variations are not globally synchronous. Changes in 143Nd/144Nd are influenced by local erosion products from continental landmasses and can therefore be different for coexisting palaeocean basins.

Recent river erosion of three coalescing debris cones in Glen Feshie has exposed a complex sequence of debris flow units. Radiocarbon dating of organic matter from interbedded buried soils reveals that the soil at the base of the sequence was buried at c. 2000 yr BP, but that the bulk of the cones accumulated since the fifteenth century AD. The episodic nature of cone development is attributable to lateral migration of the River Feshie, with periods of cone accumulation when the river occupied the far side of its floodplain alternating with periods of erosion when the river impinged on the cones. There is no evidence to suggest that recent cone accumulation is related to anthropogenic vegetation disturbance, but phases of cone accumulation show a broad temporal correspondence with periods of Late Holocene climatic deterioration. The cones are essentially paraglacial in that their continuing accumulation depends on a supply of sediment derived from glacial and periglacial deposits upslope. The form of debris-flow units indicates that flows at this site were less viscous than most ‘hillslope’ flows, and cone volumes indicate an average annual accumulation of c. 50–60 m3 of sediment over the past c. 300years.

Air photo interpretation and geochemistry have been used to supplement sparse field data in compiling a reconnaissance geological map of the area around the Lecht. Upper Appin and lower Argyll Group rocks are exposed, the best marker horizons being correlatives of the Appin and Jura Quartzites. Scatter plots, Q mode factor analysis and Pearson correlation coefficients of geochemical data were successfully used in the correlation of the pelite and limestone outcrops. The presence of major recumbent folds is inferred. The area is cut by numerous minor faults which are thought to be related to a major transcurrent fault, the probable north-eastern continuation of the Loch Tay fault, which was active in Lower Old Red Sandstone times.

The Lecht manganiferous ironstone is a seepage-bog ore type deposit derived by weathering of the local Dalradian sequence. Despite intensive leaching, this sequence still shows anomalously high levels of several elements, particularly Mn, Ba and Zn. In addition, stratiform sphalerite and manganiferous garnet are present in Blair Atholl Subgroup limestone and pelite horizons, respectively. Mineralogical and geochemical evidence suggests the presence of Zn–Pb–(Ag)–(?Au) exhalative mineralisation within the upper Appin Group Dalradian of the region, of which the Lecht represents the distal manganiferous expression.

Fossil assemblages can give quantitative estimates of palaeotemperatures, by comparison with modern biota, only in the recent geological past. Oxygen isotopic palaeotemperatures on calcareous or phosphatic fossils are potentially available for the whole Phanerozoic. Their reliability is limited by physiological effects (generally believed minor), preservation (for which criteria are available), and by uncertainty in the isotopic composition of ancient seawater. The latter is greatly affected by glaciation. In the Cenozoic, the relative contribution of ice-volume change and temperature change in producing isotopic variations can largely be resolved by analysing planktonic and benthic foraminifera in deep-sea cores. For earlier times only continental shelf deposits are available. In the Mesozoic, reasonable assumptions about ocean isotopic composition lead to palaeotemperature estimates that suggest generally higher temperatures than at present, particularly for mid- to high latitudes. This agrees with estimates based on biotic distributions. Late Palaeozoic glaciation is reflected in variable isotopic compositions in high palaeolatitude areas. In the earlier Palaeozoic, well-preserved fossils indicate either oceans enriched in 16O compared to today's or generally higher temperatures; controversy continues about the relative importance of the two effects.

Forty-one species assigned to thirty-seven named genera of trilobites are described from the Tangtou Formation at Tangshan and Lunshan, in Jiangsu Province, SE China. Nankinolithus nankinensis Lu, the Zone fossil of the upper part of the Formation, is abundant. Many Tangtou Formation species occur also in the Huangnehkan, Linhsiang and Chiencaokou formations, and all are considered to be of early Ashgill age. The trilobites are closely related to those of the Staurocephalus clavifrons Zone (Rawtheyan) of Poland, demonstrating the long duration and wide extent of deeper water faunas. There are also close links with the Ashgill faunas of Central Asia.

One new species, Amphitryon cheni, is established. The following morphological features are described: a small remopleuridine hypostome is unlike any other in construction; Nileus transversus retains genal spines to full grown size in some specimens, but loses them in others; the hypostome lacks the posteromedian cusp of other species. The hypostome of Paraphillipsinella is strongly styginid in conformation, and unlike that of Phillipsinella. Telephina convexa is the only species known with three spines on the librigena. The arrangement of pits in Nankinolithus nankinensis, the type species, is described, including illustrations of the irregularities which occur in every fringe. A small bulb at the tip of the hypostome of Ovalocephalus (= Hammatocnemis) bears two backwardly pointing spinules, one above the other, on the vertical posterior margin. Three types of protaspides, and numerous meraspid parts are described.

The basic properties of living systems are remarkably consistent and involve energy interactions between intracellular and extracellular environments. These interactions predispose living systems to deposit minerals from many solutions. The evolution of biomineralisation was not a single cellular invention but rather the association and perfection of a few of these fundamental properties of cell biology. The components of biomineralisation systems involve some mechanism for modifying the activity of at least one ion, an interface for initiating and possibly controlling crystal growth, a diffusion limited size and a mechanism for manipulating the growth of the crystal lattice. The evolution of these components of biomineralisation in the context of geological time inevitably concentrates on the Precambrian–Cambrian boundary. Over a time scale of less than 50 × 106 years there was a proliferation of metazoan phyla, the mineralisation in a large number of taxa and the exploitation of a diverse set of processes involving agglutinated sediments, silica, phosphates and carbonates. A large number of theories have been proposed to explain why biomineralisation occurred at this particular time. Such theories should recognise the importance of the incorporation of the citric acid cycle into the cellular metabolism of many organisms and its exploitation in an aerobic environment, the development of multicellularity which enormously increased the opportunities for modifying ion activities in diffusion-limited sites, and the exploitation of browsing and carnivorous feeding habits. These influences had major effects on ecosystems and population structures and put considerable selective pressure on the advantages that could be gained from a skeleton.

Foliated to massive hornblende and biotite-bearing tonalite, trondhjemite and granodiorite comprise a terrane of batholithic dimensions in southwestern to central Newfoundland. These rocks intrude and include Ordovician ophiolite fragments and metasedimentary rocks of Fleur de Lys type, and are cut by a suite of Silurian gabbro-diorite and norite and Siluro-Devonian (?) granite intrusions.

A U/Pb (zircon, sphene) age of 456 ± 3 Ma (2σ) and a K/Ar (hornblende) age of 455 ± 14 Ma (previously reported) for a representative least-deformed tonalite of the Southwest Brook Complex indicate that it crystallised and cooled in Caradoc time. A less precise U/Pb (zircon) age of 428 ± 41 Ma (2σ) is measured for tonalitic Cape Ray Granite in southern Newfoundland. On discrimination diagrams which use Rb, Nb and Y contents to infer tectonic setting, these rocks fall in the field of volcanic arc granites. The occurrence of zircon cores with average ages of 1430 + 18/–17 and 1541 ± 173 Ma (2σ) also indicate that the magmas formed in part by partial melting of Proterozoic crust, or sediments derived from such crust. It is suggested that the tonalitic magmas were generated during the Taconic Orogeny in an arc: continent collision zone at the ancient margin of eastern North America.

Tonalitic rocks in western Newfoundland broadly correlative in age and chemistry with the batholith include the Burlington Granodiorite and Hungry Mountain Complex, as well as allochthonous slices of foliated tonalite emplaced over Ordovician platform carbonates W of Grand Lake.

In this paper, on page 375, we published an Arenig palaeogeography in Figure 6 which showed the subduction zone off Laurentia as dipping northwards. This was a drafting error. The subduction zone should have dipped southward away from Laurentia. We apologise for this error and publish here a revised Figure 6 for the Arenig.

Although many physiological characteristics are very labile, it is proposed that some are stable enough to provide evidence concerning the routes by which terrestrial animals moved on to land. Osmotic tolerance and osmoregulatory ability are investigated first. Marine littoral invertebrates tolerate wide osmotic changes but osmoregulate little. Freshwater invertebrates osmoregulate well, but over a narrow range. Terrestrial prosobranchs of the family Pomatiasidae, which have wide tolerance, may have originated directly from the sea. The Cyclophoridae, which are intolerant, may have moved to land from fresh water. Isopods and talitrid amphipods may all have had direct marine origins with no freshwater phase. Secondly, terrestrial animals of marine origin may have blood with higher osmotic pressures than those passing through fresh water. In prosobranchs, isopods and amphipods, the evidence agrees with the conclusions suggested from character one. Thirdly, the production of hypo-osmotic urine in terrestrial animals may be evidence of freshwater origin. The evidence again supports the initial suggestions about prosobranchs and amphipods. It is concluded that because there is little selection pressure acting on these characters on land, they can be used as evidence of ancestry. Possible use of further characters is discussed.