A nesw Ophiceratid genus and species Durvilleoceras woodmani is described from the late Middle Permian Greville Formation of New Zealand, with Episageceras aff noetlingi Haniel. The horizon is close in age to the Kathwai dolomite of the Salt Range, which also has a mid-Permian Ophiceratid species, Ophiceras connectens Schindewolf. The occurrence of these two species shows that the Ophiceratidae cannot serve as an index of early Triassic rocks. The so-called basal Triassic Griesbachian Stage may prove to be closely linked to the Permian period. The key Griesbachian ammonoid genus Otoceras is related to Permian genera, with no later survivors. Moreover the widespread occurrence of Permian-type Productacea and other brachiopods in beds of the Griesbachian Stage in North America and Himalayas also suggests that the Griesbachian is Permian rather than Triassic. To judge from faunas, the start of the Triassic could be based on the incoming of numerous ammonoid families and Triassic brachiopods in the Smithian Stage. The intervening Dienerian Stage between the Griesbachian and Smithian stages is relatively barren of faunas, reflecting some sort of catastrophe at the end of the Paleozoic Era, but has mainly Permian survivors. Such a picture of the Paleozoic–Mesozoic boundary conforms with the intention if not the practice of early paleontologists.

The Silurian and Lower Devonian graptolite-bearing strata are widely distributed in both the platform and geosynclinal areas in the USSR. They are represented by black clay and siliceous shales, marlstones and argillites. In the main area of their distribution the regional zonal standard is established based on graptolites. They serve as the most detailed stratigraphical base for geological mapping and exploration and are used in the regional and inter-regional correlations. Correlation with other countries and continents is carried out by comparison of regional zonal successions with the unified standard of graptolite zones. The latter is compiled from the regional zonal subdivisions of the British, Czechoslovakian and Polish type sections. The zonal stratigraphy based on graptolites allows the establishment of the limits of the Silurian System and Stages/Series in the USSR. The Silurian and Lower Devonian sediments in the USSR are characterized by various geographically widespread graptolite assemblages. The most complete zonal subdivision is worked out for the Lower Silurian. The Upper Silurian and Lower Devonian zonal stratigraphy requires elaboration and precision in the future. The importance of graptolites in solving general geological problems particularly for establishing detailed stratigraphy of regions of industrial explorations considered.

The asymmetry of the continental margin around southern Africa can be related to Mesozoic sediment thicknesses, which were in turn controlled by the local structural setting. On the west coast, the Orange Basin sediments were built out as a thick wedge over the margin of the continent by discharge from the Orange River, whereas on the Agulhas Bank, sedimentation was confined to continental areas. Off the east coast the extremely narrow margin of the continent did not form an effective trap for sediments, which were readily carried beyond it. Cainozoic sediments are thin, and modify the Mesozoic sediment pile only locally on the outer shelf and slope.

In the Cayman Islands a core of Miocene and Oligocene crystalline limestones is overlain unconformably by limestones of the Pleistocene Ironshore Formation. Within this Formation five separate depositional environments are recognized. A reef facies contains corals still in their growth position. This reef facies is succeeded by a back reef facies, followed by a lagoonal facies. The lagoonal facies contains a diverse molluskan fauna of 75 species which differs considerably from that found in the present lagoons around the island. Rocks of these facies are overlain in places by ridges of calcarenite, considered to be shoal deposits. Higher ridges which overlie the Tertiary limestones and reef facies rocks are interpreted as beach ridges. It is thought that the Pleistocene sediments were deposited around a gradually subsiding core of Tertiary rocks.

The Ballantrae complex, variously interpreted in the light of plate tectonics, is reappraised on the basis of comparisons with ophiolites of the Newfoundland Appalachians and the southwestern Pacific. All the main components of a typical ophiolite sequence can be recognized although the sequence has been greatly disturbed by post-emplacement Caledonian deformation. The presence of a garnet granulite-amphibolite ‘aureole’ beneath the peridotite member of the complex is confirmed, thus establishing the affinity of the complex to other ophiolite-amphibolite associations of the Appalachian and Alpine systems. Rock units previously described as agglomerates are re-interpreted as olistostromes, and the important Pinbain Beach ‘shaly group’ containing fragments of ophiolitic debris, garnet-ariegite, and glaucophane schist, is considered to be a Wildflysch unit of Middle Arenig age. The olistostromes were deposited following obduction of oceanic lithosphere represented by the ultramafic and mafic rocks of the Ballantrae complex. Recognition of the complex as overthrust ophiolite removes certain constraints on the position of a Lower Paleozoic subduction zone within the Southern Uplands.

A suite of Tertiary alkaline porphyritic microgranites and hybrid and peralkaline granite from northwest Pakistan is described, with six rock analyses (five of them new). The microgranites, an earlier group of which some contain garnet, have undergone metamorphism, lacking in the granites. The microgranites are shown to be precisely similar to those from the Shewa–Shahbazgarhi area, for which four analyses (two of them new) are presented, and related to a third group from Tarbela. The mineralogy of the rocks is discussed, with seven new analyses of aegirine, riebeckite, ferrohastingsite and astrophyllite, and X-ray determinations of the feldspar compositions. The granites are considered to be related to the undersaturated syenites and associated rocks of Koga, and a petrogenetic scheme for the alkaline province is presented, with a K/Ar age determination, tentatively deriving the source magma (quartz trachytic) from a Himalayan tholeiite.

The melting intervals of basaltic magmas are investigated in detail at various pressures, as the size of the interval has an important bearing on the genesis of igneous rocks. Tholeiitic magmas do not have a more pronounced four phase proximity at low pressures than at higher ones. This result seems to oppose the generally accepted low pressure character of these magmas; but as there is a general decrease in melting intervals with increasing pressure, the four phase proximity is nevertheless sustained. The melting intervals of alkaline rocks decrease rapidly with increasing pressure. Small variations in the temperature may therefore generate large variations in the composition of the liquids developed at high pressures.

Potassium–argon age studies on the central intrusion complexes of Ardnamurchan, Western Scotland, indicate that they were emplaced at a time between 59 and 61 Ma ago. The time period associated with the cooling was probably less than of the order of a million years. The temporal setting of the Ardnamurchan complexes in the context of the other British Tertiary igneous centres is examined in the light of the new data.

The Eller Beck Formation is a thin marine intercalation in a predominantly non-marine Middle Jurassic sequence of coal measures facies. The formation consists of thin transgressive ironstones and siltstones at the base which are overlain by a thicker regressive sequence of shale passing upwards into sandstone. The close association between changes in the local subsidence pattern and the transgression suggest that the incursion resulted from epeirogenic movement rather than from eustatic rise in sea level or a purely sedimentation-controlled change in delta distributary pattern. Facies distribution was greatly affected by local synsedimentary tectonic movement. Water depths were probably very small throughout, and tidal effects on sedimentation minimal.

In the Karawanken Mountains (SE Austria) spilites (pillow lavas and sills) are found intercalated in a sequence of Paleozoic slates and graywackes. The petrogenesis of these spilites is interpreted as follows: The pillow lavas and sills consolidated as mugearites and hawaiites, which were derived from an alkali olivine-basaltic magma by fractional crystallization. Under low temperature metamorphic conditions water entered into the rocks predominantly from external sources. The primary minerals (Na-Ca plagioclase, pyroxene and glass) were thus replaced either partially or completely by minerals characteristic of spilites (albite, chlorite, epidote and others). The spilites analysed are of secondary origin. They are compared with spilites and basalts of other (continental and oceanic) areas.

Feeding burrow trace fossils are recorded from the Upper Brioverian of St Ouen's Bay, Jersey. The traces resemble Sabellarites (Dawson) and represent deep water turbidity metazoans of Late Precambrian age, which are unknown in the remaining Brioverian of the Massif Armoricain.

Identifications of new material collected by Cambridge expeditions and a new find from Hopen are discussed with reference to earlier work and to the stratigraphic setting. All available generic names relating to Svalbard material are listed systematically. A supplement to the alphabetical index of records (Buchan et al., 1965) is added.

The Beinn an Dubhaich granite has previously been interpreted as a boss, and as a sheet intrusion. The present paper suggests that the structure of the granite is more complex than either of these interpretations implies, and the form is probably that of a shallow funnel intrusion.

Examination of Kaiserstuhl loess material by scanning electron microscopy reveals fine material adhering to the major particles, fracture features, carbonate overgrowths and signs of particle weathering; all of which appear typical of loess material. The carbonate overgrowths included discrete rhombic crystals, which are possibly dolomite. Alpine and Northern glaciers could have provided fine quartz material for the Kaiserstuhl loess; an Alpine source seems more likely, with perhaps some fluvial transportation involved.

The Stokes Anomaly is traced for over 3000 km, from 700 km S of New Caldedonia almost to the eastern edge of the Campbell Plateau. For most of its length the anomaly is a double feature with positive peaks from 30 km to 50 km apart. From outcrops on the western side of the Southland Syncline it is inferred that the northeastern peak is caused by Permian volcanics, and the south-western peak by the associated Permian intrusives. The anomaly is displaced dextrally by a total of 1000 km where it crosses the New Zealand land mass. About 500 km of the displacement is caused by displacement on the Alpine Fault Zone, and the remainder by distributed dextral shear and by displacement on other sub-parallel faults.

The fauna of a Lower Carboniferous (S1) fissure near Clitheroe, Lancashire, is listed. Coignouina acanthina sp. nov. (Otarionidae) is described, together with its unusual ‘eye-mound’ which bears tubercles rather than lenses. Note is made of new material of C. acanthina (Coignou) which necessitates modification of Osmólska's (1967) reconstruction of the cephalon. Carbonocoryphe hahnorum sp. nov. (Proetidae) is also described and a brief account presented of its variation, postlarval ontogeny and palaeo-ecology.

The ages of igneous rocks formed at the time of continental break-up indicate that crustal separation begins at, or shortly after, the peak of igneous activity. The present study summarizes and lends support to the conclusions of previous authors on the temporal relationship of igneous activity and continental break-up.

Horizons characterized by the trilobites Staurocephalus clavifrons and/or Phillipsinella parabola have long been regarded as significant in Upper Ordovician correlation. From time to time this idea has been formalized by the erection of Phillipsinella parabola or Staurocephalus clavifrons Zones or by equating the range of a ‘Phillipsinella parabola fauna’ with Series sub-divisions within the Standard Ordovician succession. At the present time the Phillipsinella parabola-Staurocephalus clavifrons fauna is widely regarded as indicating a Rawtheyan age (Ashgill Zones 5–7).

Recent work by the author, however, together with a review of available evidence from the literature casts grave doubts on the validity of such concepts. It is suggested that in some areas the Phillipsinella parabola-Staurocephalus clavifrons fauna may range at least as low as basal Cautleyan (Ashgill Zone 1).

Each fluvio-lacustrine cyclothem may include the following lithotypes (in ascending order): (a) irregularly laminated silts and muds; (b) regularly laminated muds and silts; (c) muds with or without molluscan partings and bands; (d) colour mottled muds. Each cycle reflects a change from flowing water conditions (fluvial) to non-flowing water conditions (lacustrine), culminating in some cases with the formation of marsh. Each lithotype is thought to represent the environmental changes which resulted from the silting up of inter-channel depressions on a flood plain. Successive cyclothems possibly reflect renewed flooding following an increase in river level during more pluvial periods.

Carboniferous conodonts are reported from knoll limestones of B2 age in North Wales and of P1a age in the Isle of Man. The faunas from both localities are associated with Goniatites crenistria Phillips and other diagnostic goniatites. The faunas are closely similar and indicate a correlation with the Avonian conodont zone of Mestognathus beckmanni–Gnathodus bilineatus.