Most of the known and most-complete Early Jurassic specimens of plesiosaurians were recovered from the United Kingdom and Germany, and few specimens from that age originate from other areas in Europe. This study describes a new plesiosaurian taxon from Toarcian deposits of Luxembourg, Microcleidus melusinae, represented by the most complete skeleton ever discovered from this country. A preliminary phylogenetic analysis places Microcleidus melusinae within Microcleididae, as a sister taxon of the species previously included in the genus Microcleidus. The new specimen studied here contributes to our understanding of the palaeodiversity of Early Jurassic plesiosaurians and confirms their high degree of ‘endemism’ and low morphological disparity.

The Fulu iron formation (IF) is an iron-rich unit in the Neoproterozoic glacial successions, South China. The major element data suggest that the iron sources of the Fulu IF are derived from binary mixing from hydrothermal and detrital loads. The Fulu IF is characterized by slightly positive Eu anomalies similar to other Neoproterozoic IFs, indicating that a high-temperature hydrothermal input may contribute little to Neoproterozoic IFs. A shift from non-existent to slightly negative Ce anomalies of the Fulu IF indicates that the IF precipitated across an iron chemocline separating a weakly oxic surface ocean from an oxygen-depleted deep ocean.

Structures including folds, cleavages, faults, joints, and lineations are described. Three periods of folding are distinguished to which three cleavages are related. In order of decreasing age the cleavages are flow-cleavage, fracture cleavage, latest fracture cleavage. The main fault systems trend north-north—east, approximately east—west, and north-west. Joints follow two principal directions. These are north-west—south-east, and north-east—south-west. The dominant lineation is north-east—south-west. At right angles to this is a north-west—south-east lineation which affects all visible foliation. It is confined to a faint crinkling.

Alternation of morphogenetic systems conditioned by wide swinging of climatic belts equatorward and poleward has been used to explain otherwise puzzling relict forms in many regions. A characteristic finely dissected landscape relief prevalent in some middle-latitude regions is in strong contrast with smoothed, coarse-textured, whalebacked, relatively featureless relief in others, notably western Europe, which are now in the humid-temperate zone. This latter is believed to be relict from the periglacial regimes of Pleistocene ice ages. In New Zealand where the former landscape type is typically developed, there has also been quite strong “periglaciation”, and in Europe running-water erosion cannot but have operated to some extent in interglacial ages. It appears that the periglacial smoothing has been pushed to the extreme limit in Europe but that its effects have been neutralized in New Zealand by the vigour of dissection in the alternating warm ages. Periglacial smothering, or “fossilization”, of fine-textured relief, which has been followed by renewed fine dissection, is very common at Wellington, New Zealand. The reasons are not clear why running water should have been (and should still be) more efficient in dissecting the New Zealand landscape than that of Europe, so that the relict periglacial landscape remains intact in the latter region.

Three areas in peninsular India are described in which the geometric orientation of the drainage pattern has led to the location of a system of parallel crustal fractures. One area is in the Archaean basement of South India. The remainder are located on Deccan basalts. The fractures are not as a rule accompanied by fault displacements, and are regarded as planes of shearing. The shearing in the Deccan basalts cuts across the post-lava dykes, and is considered to coincide with late magmatic mineralization and the break-up of the Gondwana continent in mid-Tertiary times.

The discovery of an active oil seepage in Corallian sandstones at Osmington Mills, near Weymouth, led in 1937 to an examination of the adjacent Poxwell or Moigns anticline by geologists of the D'Arcy Exploration Company, a subsidiary of the Anglo-Iranian Oil Company, Ltd. The investigations, carried out by Dr. C. T. Barber in the earliest stages, and subsequently by the junior author, consisted of surface mapping assisted by pits, trenches, auger holes, and shallow bore-holes, and culminated in the drilling of a test well in the crestal area of the anticline. This note summarizes the more important information obtained with regard to stratigraphy and tectonics.

The beginning of melting of mineral assemblages of alkali feldspar, plagioclase and quartz in the system Ab-Or-Q-An cannot be treated in terms of eutectic points in subsystems which are defined on the basis of the ratio Ab/ An. Such subsystems do not exhibit unique melting temperatures or unique compositions of the first liquid produced. It is shown theoretically and demonstrated experimentally that these three minerals may coexist with liquid over a considerable portion of the melting range.

The discovery of species of Kootenia and Bailiella known from the Middle Cambrian of western Newfoundland (“Pacific Province”) and southeastern Newfoundland (“Atlantic Province”) in limestone within volcanic rocks near New World Island, eastern Notre Dame Bay, is the first demonstration of the presence of Cambrian in the volcanic belts in North America, and also shows the mixing of forms from the two provinces.

It has been suggested that the ultrabasic and basic gneiss masses in the Lewisian near Scourie and Drumbeg are layered igneous bodies possibly containing primary igneous mineral assemblages. This hypothesis is reviewed in all its aspects and rejected on the grounds of field relationships, mineralogy, and geochemistry.

The Glacial deposits along the Norfolk and Suffolk coasts are important to geologists and archaeologists, as some of the formations here, even those which are later than the Cromer Forest Bed Series, are earlier than those of many other districts. Finds of Palaeolithic implements in this area have not so far been abundant, but an industry was recorded by us in 1938 (see Nature, 19th November, 1938, p. 912), and it is now possible to give greater details about its mode of occurrence. The geological dating of this industry will be discussed first, and the implements will then be considered from the archaeological point of view.

The following systematic account of new Lower Ordovician Brachiopods has been divided into two sections. Part I includes descriptions of a new species and variety of Resserella, two new Dalmanellas, and two new Horderleyellas, and some notes on the value of B. B. Bancroft's methods of separating Dalmanellid species and genera. In Part II two new species and a new variety of Hesperorthis, Rostricellula, and Sowerbyella respectively are recorded; an investigation of Orthis turgida McCoy shows that forms referred to this species belong either to Corineorthis, two new species of which are described, or Paurorthis.

The Malvern ridge consists of a series of Pre-Cambrian fault-blocks, which have been thrust upwards into their present positions through an overlying cover of Cambrian, Silurian, and Lower Old Red Sandstone sediments. The formation of the narrow. localized belt of folds which lie immediately to the west of the Malverns is the result of the displacement of the Pre-Cambrian basement blocks.

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.

It is well known that the crushing teeth of the Pycnodont fishes as a rule are arranged with striking regularity upon the bones which bear them, the vomer in the upper jaw and the splenials in the lower jaw. They are disposed in longitudinal series, gradually increasing in size backwards, and there is only one genus satisfactorily known (Mesodon) in which there is any marked tendency towards the frequent disturbance of this linear arrangement.

Palaeomagnetic data from the 337 Ma Magerøy dykes (northern Norway) are of exceptionally high quality, and a positive contact test along with an existing regional result from the Silurian Honningsvåg Igneous Suite attests to a primary Early Carboniferous magnetic signature. The palaeomagnetic pole (S14.8°, E320.1°, dp/dm=4.4/8.6°) is the first Early Carboniferous pole from Baltica, and implies that northernmost Norway–Greenland, the Barents Sea and Svalbard were located at tropical to low northerly latitudes at this time. Northward drift during Carboniferous times (5–6 cm/yr) as demonstrated from palaeomagnetic data is also reflected in the sedimentary facies in the Barents Sea realm, that is, a change from tropical (Early Carboniferous) to subtropical (20–30° N) carbonates and evaporites in the Late Carboniferous. The Magerøy dykes are continental tholeiites which intruded into a set of NW–SE-trending normal faults parallel to the Trollfjorden–Komagelva Fault Zone and the Magerøysundet Fault immediately to the north and south of Magerøya, respectively. These, and many other NW–SE-trending faults (onshore and offshore), were active during Late Palaeozoic extension, and the dykes were probably contemporaneous with the earliest syn-rift sedimentation in the Barents Sea (for example, the Nordkapp Basin).

Seismic refraction surveys of the buried channels of the Exe near Exmouth indicate the presence of an early period of channelling into New Red Sandstone breccias to a base in excess of −52 m* followed by a period of gravel infilling of these channels and then their partial re-excavation to a base in excess of −30 m. Terraces formed during stillstands within the early regression occur at depths of −25, −31·4, and −36 m and within the later regression at −5·8, −10.4, −13.7, −17·1, −22 and −27·1 m. Control of the orientation of the channels by fault planes within the New Red Sandstone is also indicated. Correlation of the periods of channelling with early and late Weichselian sea-level lows is suggested, indicating a middle Weichselian (Paudorfian) age for the gravels. Similarities with buried channels occurring in Southern Ireland are noted and wider correlations attempted.

Sula Sgeir consists of hornblende-gneiss with occasional biotite and augite. The whole is intersected by small pegmatite veins which merge along the borders into the gneiss. Though evidence is small, it seems probable that the island, together with North Rona, came under the influences of the Quaternary ice.

The Flannan Islands consist also of hornblende gneiss, biotite being a fairly common accessory. Numerous and varied pegmatite Veins occur throughout the islands, and in certain cases have affected the foliation of the gneiss. Owing to the proximity of the islands to the Lewis and the Harris, and the presence of adeposit of cemented sand on Eilean Ghobha, it seems probable that the Quaternary ice also reached these islands.

Since the remarkable paper by Professor Lapworth “On an Improved Classification of the Rhabdophora” was published in the Geological Magazine for 1873, a great deal of fresh information has been gathered as to these interesting fossils; but the classification given in that paper, though to some extent confessedly artificial, is still generally adhered to. Observations made by the authors in recent years lead them to suppose that that classification will in the future undergo considerable modification; but in the present state of our knowledge it serves a purpose so useful, that it is not our intention to propose any immediate change in it. Our object, on the other hand, is to bring forward certain conclusions which we have independently reached, and which will, we believe, enhance the value of Graptolites to the stratigraphical geologist, and lead to results important to the biologist. Our conclusions are based upon an examination of a large number of forms generally referred to the family Dichograptidæ; but, as we propose very briefly to indicate, they affect the relationships of Graptolites belonging to other families also.

A new enantiornithine bird is described on the basis of a well preserved partial skeleton from the Upper Cretaceous Qiupa Formation of Henan Province (central China). It provides new evidence about the osteology of Late Cretaceous enantiornithines, which are mainly known from isolated bones; in contrast, Early Cretaceous forms are often represented by complete skeletons. While the postcranial skeleton shows the usual distinctive characters of enantiornithines, the skull displays several features, including confluence of the antorbital fenestra and the orbit and loss of the postorbital, evolved convergently with modern birds. Although some enantiornithines retained primitive cranial morphologies into the latest Cretaceous Period, at least one lineage evolved cranial modifications that parallel those in modern birds.

Continental basalts ranging in age from 16.5 to 19.08 Ma crop out throughout the northern part of the Arabian plate. The basalts have distinctive petrographic characteristics such as rounded and skeletal olivine phenocrysts with abundant melt inclusions, implying the mixing of two distinct magmas. All of the analysed basalts are tholeiitic in composition. The presence of quartz xenocrysts with clinopyroxene rims in some samples indicates that crustal assimilation was probably an important process during magma ascent to the surface, and low Mg number and high SiO2 contents of the basalts clearly show that they have experienced fractional crystallization as well as crustal contamination. Variations of the major and trace elements versus MgO show that olivine+clinopyroxene+plagioclase were the main fractionating minerals. In terms of incompatible trace elements, the basalts have OIB-like signatures with a slight depletion at Nb–Ta on primitive-mantle-normalized diagrams. The basalts have slightly LREE enriched patterns with La/YbN = 5.5 to 6.7. La/Nb ratios are close to unity, suggesting the melts may have originated in the asthenospheric mantle. Partial melting modelling based on REE data imply that the melts were not produced from a single mantle source depth, which is either purely a spinel- or garnet-peridotite end member. The samples lie on a binary mixing line between low-degree melts (<5%) from garnet-peridotite and higher-degree melts (>10%) from spinel-peridotite sources on a plot of La/Yb v. Dy/Yb, requiring interaction of melts derived from both garnet- and spinel-peridotite fields. Melts originating from both sources were initially tapped by distinct magma chambers, which subsequently hybridized into a single flow. Hybridized magma ascended to the surface along Neogene strike-slip faults, which are linked to the Dead Sea Fault Zone.