The Habberley Formation overlies the Shineton Shale Formation in the Shelve Inlier, Shropshire, and includes the youngest Tremadoc strata known from the Welsh Basin. It probably represents deposition during the interval cut out by the sub-Arenig unconformity in North Wales, and removed by the sub-Caradoc unconformity in the Wrekin district. There is no angular unconformity between Tremadoc and Arenig in the Shelve Inlier. The Habberley Formation is likely to correlate in part with the Hunnebergian Stage of Scandinavia. It was deposited probably in a largely stagnant basin, and records a shallowing-upwards sequence, prior to the Arenig transgression of the Stiperstones Quartzite. A sparse trilobite fauna proves the presence of the Angelina sedg vickii Biozone, and a succeeding interval is characterized by Asaphellus cf. graffi. The trilobites are briefly described; they include the first undistorted material of Angelina sedgwvickii. The brachiopod Lingulella bella (Walcott), hitherto known only from eastern Newfoundland, is described by A. W. A. Rushton.

The magnetic susceptibility anisotropy of specimens of a glacial till is described and used to define a magnetic fabric. This is compared with the fabric established by small particle and stone orientation. The maximum susceptibility direction is shown to be similar to the preferred direction of the long axes of particles and stones.

It is suggested that the rock-suite, characteristic of the discordant bathyliths and ranging in composition from ultrabasic to ultra-acid, is formed from two magmas, a basaltic and a granodioritic, that the basic rocks are emplaced among the geosynclinal sediments before the introduction of the acid magma, and that intermediate rocks are hybrids. Further, it is suggested that hybridization takes place in two stages: first, by reaction between basic rocks and water and carbon dioxide, released from sediments as a result of deep-seated metamorphism, and rising in advance of the acid magma; and secondly, by the magma itself. The first intrusions carry shattered country rocks and are stock-like bodies, and these are followed by successive emplacements of granodiorite, the earliest of which envelop most of the stocks and are, thereby hybridized to form tonalites. Only those stocks near the margins of the later intrusions are preserved, and hence occur as satellites about the larger more acid bodies.

The order of intrusion, the grainsize of the basic hybrids, and the occurrence of hornblende is discussed and it is concluded that dioritic rocks and dioritic magmas originate at a high level in the geosynclinal pile.

The igneous rocks of the Stanner-Hanter district are included within the Geological Survey I-inch map, sheet 56 S.E., (Old Series), and form three hog-backed hills, Stanner Rocks, Worsell Wood, and Hanter Hill, which are prominent features in the country between New Radnor and Kington, close to the Welsh border. This line of hills trends from south-west to north-east, though the separate ridges are arranged en échelon. Stanner Rocks (I,08I feet), is separated from Worsell Wrood (about 940 feet), by the alluvial plain of the Gilwern Brook, while there is a low col between Worsell Wood and Hanter Hill (I,36I feet).

Sedimentary dykes from the Dalradian of the South-west Highlands of Scotland are described. It is suggested that these features are characteristic of certain geosynclinal environments.

The Neoproterozoic–Palaeozoic transition (NPT) around 600 Ma ago was a critical time interval when the Earth experienced fundamental change, manifested as climatic extremes – ‘snowball Earth’ – followed by the emergence and rapid diversification of animals – ‘Cambrian explosion’. How animals and environments co-evolved, and what caused these fundamental changes to the Earth system during the NPT, is a great scientific puzzle, which has been a rapidly developing frontier of interdisciplinary research between bio- and geosciences. South China preserves a complete stratigraphic succession of the NPT developed in various facies ranging from shallow to deep marine realms with extraordinarily well-preserved, successive fossil biotas in various taphonomic settings (Zhu, 2010; Fig. 1), making it a key area and global focus of studies in the field over recent decades. Indeed, the current narrative of early animal evolution has largely been based on the fossil biotas from South China. These include: (1) the world's oldest microscopic animal fossils with cellular details from the early Ediacaran Weng'an biota (Doushantuo Formation); (2) putative macroscopic animal fossils preserved as carbonaceous imprints from the early Ediacaran Lantian, Wenghui and Miaohe biotas (also Doushantuo Formation); (3) typical late Ediacaran faunas, preserved in dark limestone (Shibantan biota) and as large and poorly mineralized tubular animal fossils (Gaojiashan biota), both from the Dengying Formation; (4) phosphatized small shelly and soft-bodied animal fossils from the early Cambrian Meishucun and Kuanchuanpu faunas; and (5) Cambrian fossil Lagerstätten (Chengjiang, Guanshan and Kaili faunas) with typical Burgess Shale-type soft-bodied preservation.

The Mingshui–Jilasitai–Suolun area, located in the central part of the Great Xing’an Range, is characterized by large volumes of alkali feldspar granites. However, the formation time and tectonic setting of these rocks remains controversial owing to a lack of precise geochronological and detailed geochemical data. In this paper, we report new SIMS U–Pb zircon ages and mineralogical, petrographical and geochemical data for Lower Cretaceous alkali feldspar granites from the Mingshui–Jilasitai–Suolun area. The SIMS zircon dating results indicate that these granites formed at 133.6–135.9 Ma. The mineralogical, petrographical and geochemical data show that these granitic rocks belong to highly fractionated I-type granites. Combined with the regional geology data, we propose that the formation of the Lower Cretaceous alkali feldspar granitic rocks was related to an extension induced by delamination of the lithosphere that arose from subduction of the Palaeo-Pacific plate.

A review of isolated data from the literature and our own observations make it possible to establish a model of the stratigraphical history of the Ordovician on the southern margin of the Brabant Massif. The succession is composed of seven informal formations, totalling a minimum of 2500 m of sediments, mainly comprising mudstones, siltstones and sandstones. This succession is compared and partly correlated with the sections observed in the adjoining areas, in the Bande de Sambre-et-Meuse, the Stavelot and Rocroi Massifs and the Remscheid–Altena and Ebbe anticlines (western Germany).

The mid- to Upper Permian Radok Conglomerate, the lowermost formation of the Permo-Triassic Amery Group, crops out in the Beaver Lake area of the northern Prince Charles Mountains, East Antarctica. Outcrop is confined to a north-south elongate, fault-bounded corridor interpretedas a remnant of a continental extensional basin formed during Late Palaeozoic times. This basinforms a small part of the much larger Lambert Graben, a major continental rift system. The RadokConglomerate consists of interbedded conglomerates, argillaceous sandstones, siltstones, and minor, thin carbonaceous siltstones and coals. Textural, petrographic, palaeocurrent and other data suggestlocal derivation from Precambrian massifs to the immediate west, during a period of fault activity.The unit is a minimum of 400 m thick, the base being unexposed, and grossly fines upward. It isabruptly overlain by quartzo-feldspathic sandstone-dominated rocks of the Upper Permian Bainmedart Coal Measures. Seven recurrent lithofacies have been recognized with the Radok Conglomerate, and are interpreted as the products of poorly-confined stream flow, sheet flow and sediment gravity flow processes, suspension fallout in shallow standing water, and organic sediment accumulation in peat-forming wetlands. The unit as a whole is interpreted as having accumulated as a coarse alluvial apron along the western margin of a ?graben extensional trough. Similar, though poorly exposed, facies are exposed on the eastern margin of the basin and may reflect similar depositional systems. Towards the top of the Radok Conglomerate, typical Radok lithologies are interbedded with quartzo-feldspathic sandstones derived from the south, precursors of the overlying Bainmedart Coal Measures. Interference between transverse (Radok) and axial (Bainmedart) drainage is possibly related to progressive infilling of extensional topography, thereby allowing axially flowing rivers to avulse increasingly into the Beaver Lake region from the main Lambert Graben.

The paper contains eight analyses of primary and recrystallized pyroxenes from the layered ultramafic peridotite at Dawros. The assemblages in which these pyroxenes occur are compared to those from other peridotites and some comments are made on the pyroxene sequence. Consideration is also given to the problems arising as the result of the metamorphism of the primary igneous accumulate at Dawros.

The mylonitic character of the peridotites of St. Paul's Rocks on the Mid-Atlantic Ridge was reported in a contribution by the writer (Tilley, 1947), these ultrabasics then being referred to as dunite or peridotite mylonites. The available chemical analytical data were assembled in that paper and a new analysis provided of a two-pyroxene representative. The type carrying porphyroclastic amphibole was represented by an analysis by Washington (1930) but it was shown that this analysis erred in its alkali determination, and that the reported occurrence of jadeite could not be confirmed.

Recent (Quaternary) lava fields, such as those of Citlaltépetl (Pico de Orizaba) volcano in Mexico, are excellent places to obtain precise measurements of flow-field dimensions that can be used to estimate volume, eruption duration and effusion rates. The relationship between these parameters and the influence of some other interrelated features such as lava composition, superficial structures and lava type are important tools that can help to infer conditions when the lavas were active and thus improve understanding of how flow fields grow. The Holocene lavas of Citlaltépetl volcano are homogeneous in composition (dacites) and are generally blocky with well-developed levees. The eruption duration obtained for the Citlaltépetl lavas by a method proposed by C. Kilburn and R. Lopes presents a good correlation with the different lava types morphologically classified here. Results from that method compare favourably with the inferred effusion rates estimated by an empirical cooling method (Graetz). The lavas show different behaviour, mainly controlled by fluctuations in the effusion rate that promote changes from single- to multiple-flow style. The maximum distance achieved by a flow is directly proportional to the effusion rate in Citlaltépetl lavas, but it is always lower for multiple flows, independent of the volume of erupted lava. Observations of Citlaltépetl lavas can be used to understand how lava flow growth occurs on other volcanoes.

The fabric of sedimentary rocks in lacustrine archives usually contains long and continuous proxy records of biological, chemical and physical parameters that can be used to study past environmental and climatic variability. Here we propose an innovative approach to sedimentary facies analysis based on a coupled geomicrobiological and sedimentological study using high-resolution microscopic techniques in combination with mineralogical analyses. We test the applicability of this approach on Lake Son Kul, a high alpine lake in central Tien Shan (Kyrgyzstan) by looking at the mineral fabric and microbial communities observed down to the nanoscale. The characterization of microbe–mineral interactions allows the origin of four carbonate minerals (e.g. aragonite, dolomite, Mg-calcite, calcite) to be determined as primary or diagenetic phases in Lake Son Kul. Aragonite was mainly of primary origin and is driven by biological activity in the epilimnion, whereas diagenetic minerals such as Mg-calcite, calcite, dolomite and pyrite were triggered by bacterial sulphate reduction and possibly by methanotrophic archaea. A new morphotype of aragonite (i.e. spherulite-like precursor) occurs in Unit IV (c. 7100–5000 cal. BP) associated with microbial mat structures. The latter enhanced the preservation of viral relics, which have not yet been reported in Holocene lacustrine sediments. This study advocates that microbe–mineral interactions screened down to the nanoscale (e.g. virus-like particles) can be used successfully for a comprehensive description of the fabric of laminated lake sediments. In this sense, they complement traditional facies sedimentology tools and offer valuable new insights into: (1) the study of microbial and viral biosignatures in Quaternary sediments; and (2) palaeoenvironmental reconstructions.

The preglacial platform of marine erosion discussed in the following pages was first discovered in the Island of Colonsay in the course of the geological survey of that island carried out in the summer of 1907, and the information then acquired is communicated with the permission of the Director of the Survey. The subsequent tracing of the shoreline in the adjoining islands was effected with the aid of a Government grant for scientific research in the gift of the Royal Society of London. For clearness and convenience of reference the subject will be treated under the following heads:—

I. Introductory remarks indicating the aims of the investigation.

II. Colonsay and Oronsay—description of the preglacial platform.

III. Islay.

IV. Mull and Iona.

V. The Treshnish Islands.

VI. Conclusion, setting forth the present state of the subject.

Some essential features of the general tectonic description of a region are outlined under the above heads. Tectonic style is the product of facies and orientation in their distinctive sequence, and is assumed to be independent of date. A type of tectonic sequence is outlined from Ny Friesland, Spitsbergen, with a distinct late stage elongation along the fold axes.

K—Ar age measurements on Esquibel Island, southeastern Alaska yield a minimum age of about 433±3 Ma for the Zone of Monograptus cyphus of the Lower Silurian. An age of approximately 435—437 Ma is estimated for the Ordovician—Silurian boundary.

Tectonic and thermal perturbations, related to emplacement of granodiorite in the upper continental crust, have been investigated in the late-Hercynian basement exposed in southern Calabria (Italy). Here, the structural aureole is marked by the presence of a major rim fold adjacent to the intrusive contact for a length of at least 20 km. Geometrical analysis of the structural aureole and related foliations, lineations and crenulations reveals that the perturbed zone is at least 3000 m wide and characterized by an open synform trending nearly parallel to the intrusive contact. This pattern is compatible with a laccolith-like mode of magma emplacement, related to the accretion of the pluton that shouldered weak phyllitic and slaty wall rocks. The metamorphic aureole, about 1800 m wide, is characterized by biotite, cordierite and andalusite that appear sequentially in spotted schists and hornfelses approaching the intrusive contact. The peak assemblage equilibrated between 535 and 590°C at pressures between 175 and 200 MPa, confirmed by Al-in-hornblende barometry on granodiorite. Microstructural analysis allowed the inference of a time lag between the thermal and tectonic perturbations. With the aid of thermal modelling it was possible to quantify the time required to reach the peak temperature at a distance from the intrusive contact where cordierite spots and andalusite porphyroblasts clearly overprint crenulations. This estimate represents the time limit to accomplish deformation in the inner portion of the aureole and thus indicates a minimum strain rate of 4 × 10−14 s−1 within the country rocks during granodiorite intrusion.

Nineteen members of the Working Group attended the meeting and constituted a good representation in experience, variety of specialist knowledge of disciplines within geology, and first-hand knowledge of appropriate global stratigraphy. The following resolutions as a whole were accepted, as an account of the meeting by those present, with a large majority. The minority of four who did not accept Resolution I requested that the Minority View (see below) should be recorded but it was decided not to include it in the Resolutions.

During the past year excavations have been continued in the deposits filling the channel cut through the Coombe Rock of post-Early Mousterian (Levalloisian) age and situated between Northfleet and Swanscombe. “The floor” at the base of the succession has continued to yield a fine series of contemporary Middle Mousterian (Levalloisian) implements, together with artifacts derived from the Coombe Rock and earlier deposits. Associated with the implements are the remains of Elephas primigenius, Rhinoceros antiquitatis, Microtus arvalis, M. anglicus, and M. nivalis.

A new xinjiangchelyid turtle, Kalasinemys prasarttongosothi n. gen. n. sp., is described on the basis of skull and shell material from the Upper Jurassic Phu Kradung Formation at Phu Noi locality, Kalasin Province, in NE Thailand. This second xinjiangchelyid turtle from Phu Noi is distinct from Phunoichelys thirakhupti by the smooth shell surface, the presence of a cervical notch, and vertebral 1 narrower than nuchal. The skull presents an arterial system characteristic of the Xinjiangchelyidae (basal Eucryptodira), and its outline is similar to that of Annemys spp. known from the Middle–Late Jurassic of China and Mongolia, but distinct from the latter mainly by the wider triturating surface, smaller foramen palatinum posterius and the shape of the prefrontal and frontal, as well as that of the basisphenoid and basioccipital. Based on the turtle assemblages, the correlation with mainland Asia further supports a Late Jurassic age for the lower part of the Phu Kradung Formation where Phu Noi site is located stratigraphically. Our study provides new insight on the evolution of the basal eucryptodiran turtles in Asia.