On the eastern side of the Mount Lofty Ranges of South Australia, impure marbles and calc-silicate rocks characterized by assemblages rich in scapolite and pyroxene have been formed on a regional scale by high grade metamorphism of limestones and calcareous shales. It is suggested that this metamorphism is essentially iso-chemical and that even chlorine in the scapolite (Me 55[60) could have been derived from the original sediments.

A secondary paragenesis consisting of epidote, actinolite, and calcite at Tungkillo and epidote, actinolite, calcite, and garnet at Milendella, is the result of late metasomatism and reaction associated with the formation of granites, migmatites, and veined gneisses. At Tungkillo, outside the sphere of granite activity, the secondary, retrograde assemblage is due to limited metasomatism chiefly involving the introduction of water, whereas at Milendella where marbles and calc-silicate rocks are intimately associated with granitic rocks, reaction and metasomatism giving rise to the secondary minerals has been more intense. Here garnet of the andradite-grossularite series has developed.

Preliminary observations indicate that the rhythmically varied layers of ultrabasic rock in Rhum form part of a layered intrusion built up from below rather than a series of separate injections.

The basal Purbeck of Dorset includes interesting “dirt-beds” or fossil soils. The limestones, previously considered freshwater, are here shown to be largely of marine algal origin containing species of Ortonella, Girvanella, and Solenopora and presumed algal stromatolites. Petrographic evidence of anhydrite, gypsum, and celestine suggests evaporitic conditions during their formation. This is supported by the presence of ostracods belonging to marine or super-saline species, and by the scarcity of other fauna.

It is quite clear that Professor Joly's presentation of his theory of basaltic cycles is, taken alone, far too simple to match the complex details of geological history. In a former paper I attempted to extend the principles he has so persuasively advocated, by adding the conception of a peridotite cycle of longer period, and I was careful to point out that even this extension led to no more than a rough approximation to the actual realities of the earth's behaviour. As soon as details are considered, the pursuit of the subject leads its explorer into a maze of difficulties, because of the many interfering factors that must also be taken into account. Nevertheless, a broad survey of the earth's history suggests that Joly has surmised what is so far the only kind of process that even begins to correspond with the dominant facts. And that, without any qualification, is a very great achievement.

In view of Mr. J. A. Butterfield's account of outgrowths on zircon in the Millstone Grit of the Pennine region (Geol. Mag., LXXIII, 1936, 511–16), it may be of interest to record the occurrence of similar grains in the Middle Jurassic sandstones of Yorkshire.

South of Clew Bay, Co. Mayo, Wenlock strata, cut off to the north by a belt of serpentine marking the Highland Boundary, are divisible into three stratigraphical groups. The succession is repeated by a syncline overturned towards the south, which is modified by north-west cross-folds. The Wenlock strata have undergone low-grade “regional” metamorphism, in spite of which fossils have been preserved at a few localities.

The geological feature which strikes the traveller in Iceland perhaps most forcibly is the complete contrast afforded by the well-ordered, level, or gently dipping basalt sheets with almost negligible tuff intercalations which constitute the Pre-glacial Kainozoic Plateau and the Late-glacial and Recent volcanic formations, and the enormous, chaotic, rarely-bedded accumulations of the Palagonite Formation in which lava flows are subordinate in amount; and he is at once presented with the question: Why did igneous action which produced lava sheets in Pre-glacial times result in dominant tuffs and breccias in the period which followed, and then revert to the production of lavas in later times ? This question has not yet been fully answered.

The first conclusive evidence for Silurian rocks in the Paraná Basin, Brazil, was reported in 1985. This evidence was based on organic-walled microfossils, principally spore tetrads, and associated phytoplankton (‘acritarchs’ and prasinophytes), the first recovered from the Vila Maria Formation on the northeastern rim of the Basin. The spore assemblage was typical of Gray's Microfossil Assemblage Zone I; size-frequency data for the tetrads suggested an early Silurian (early Llandovery; Rhuddanian) age. We now document a new MA Zone I occurrence of spore tetrads together with a few single trilete spores, from the southwestern rim of the Paraná Basin, Paraguay. The single spores are among the earliest known to have normally dissociated from a tetrahedral tetrad. Size-frequency data for the tetrads suggest a late Llandovery, pre-C5 (mid-Telychian) age. These spores, together with phytoplankton and chitinozoans, were recovered from beds laterally equivalent to the Vargas Peña Shale at the type locality from which Llandovery diplograptids and monograptids are known. Llandovery age rocks on the southwestern and northeastern borders of the Paraná Basin, c. 1400 km apart, suggest that early Silurian rocks were extensively distributed throughout southern Brazil and adjacent Paraguay. Close conformity between the age reference obtained with graptolites and spore tetrads again demonstrates the stratigraphic utility of early Silurian spores in providing reliable age determinations for otherwise unfossiliferous rocks. Spore tetrad assemblages available from the Malvinokaifric Realm (South America, Africa, Arabia) represent a distinct phytogeographic unit contrasted with spore tetrad assemblages from the North Silurian Realm of North America and parts of Europe.

Inclusion textures within garnets are often used to demonstrate the relationship in time between garnet growth and deformation. The evidence for syntectonic growth is discussed, and it is shown that several thin sections are required before an accurate interpretation can be made. The patterns predicted by Powell & Treagus (1967) are matched with natural examples, and a mechanism for the aevelopment of these fabrics is suggested.

The Datong pluton, the largest early Palaeozoic granitoid in the Western Kunlun Orogenic Belt (WKOB) in NW China, is a typical appinite-granite complex. It consists of diorites, quartz diorites, monzodiorites, quartz monzodiorites, monzonites, quartz monzonites, syenites, granodiorites and monzogranites. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U–Pb dating yielded crystallization ages of 459 ± 3 Ma for the quartz monzonites and 452 ± 5 Ma for the monzogranites (Late Ordovician). The rocks possess a wide range of SiO2 (56.0–73.4 wt %), MgO (0.17–4.55 wt %) and Mg no. (25–60), with high K2O (2.83–5.29 wt %) contents, exhibiting high-K calc-alkaline to shoshonitic traits. They are characterized by enrichments in large-ion lithophile elements (LILEs) and light rare Earth elements (LREEs), as well as depletions in high-field-strength elements (HFSEs). The rocks have initial 87Sr/86Sr ratios of 0.7086–0.7185, negative εNd(t) values of –3.72 to –1.79 and εHf(t) values vary from –1.6 to +4.7. These features are modelled to show that they were most likely derived from an enriched lithospheric mantle source and that fractional crystallization with minor crustal contamination was involved in their petrogenetic process. Considering the distribution and chronology of the Palaeozoic intrusions – such as Kegang, Bulong, Qiukesu, Yierba, North Kudi, Dongbake, Buya, Ayilixi and Warengzilafu granitoid plutons with ages of c. 420–530 Ma – in conjunction with the Palaeozoic metamorphic overprinting in the WKOB, we propose a divergent double-subduction model to explain the destruction of the Proto-Tethys Ocean and suggest that the Datong pluton was likely emplaced in a post-collisional setting following the termination of subduction in response to slab break-off.

Vermiform burrows, which are common in the Lower Greensand, can be used to estimate the relative rate of sedimentation, repeated penetration by burrowing organisms being taken as indicating slow deposition, a single undisturbed penetration as indicating rapid deposition. Application of this criterion is illustrated by reference to the Ferruginous Sands of the Isle of Wight.

Megacephalosaurus eulerti is a large macropredatory plesiosaur representing one of the last members of the diverse pliosaurid clade Brachaucheninae. The taxon was established upon a nearly complete skull including the mandible and fragments of the postcranial skeleton originating from the lower middle Turonian (Upper Cretaceous) of Kansas, USA. Owing to its age, reasonable completeness and its state of preservation, M. eulerti bears important anatomical details regarding the last brachauchenines. Here we assess the dentition of the taxon, compare the teeth to those of other thalassophonean pliosaurids and comment on the utility of these results for inferences of the phylogenetic relationships of the last brachauchenines. Additionally, we provide remarks on the cranial anatomy of M. eulerti, revise character scores of this taxon used in current phylogenetic studies and address the phylogenetic relationships within Brachaucheninae. Parsimony analyses, aimed to test different character sampling and tree-search strategy, inferred only a single unambiguous synapomorphy uniting a clade formed by mid- to Late Cretaceous brachauchenines: presence of subcircular rather than subtrihedral/trihedral cross-sectional shape of the teeth. Still, the last brachauchenines (Brachauchenius and Megacephalosaurus) can be roughly characterized by a switch from anisodont to subisodont dentition and reduction of their tooth count. Nevertheless, the overall knowledge of the origin, phylogenetic relationships and distinguishability of brachauchenine pliosaurids remains poor and represents a subject for further extensive studies and modifications in taxon and character sampling.

In order to improve the understanding of how the high northern latitudes responded to the escalating warming which led to the middle Cretaceous super greenhouse climate, more temperature proxy records from the High Arctic are needed. One of the current obstacles in obtaining such records is poor age control on the Lower Cretaceous strata in the Boreal region. Here, we provide a biostratigraphic framework for the Rurikfjellet and Helvetiafjellet formations representing the lower part of the Lower Cretaceous succession on Spitsbergen. We also attempt to date the boundary between the Agardhfjellet and the Rurikfjellet formations. This study is based on dinoflagellate cysts (dinocysts) from three onshore cores (DH1, DH2 and DH5R) and three outcrop sections (Bohemanflya, Myklegardfjellet and Ullaberget). Relatively abundant and well-preserved dinocyst assemblages from the Rurikfjellet Formation date this unit as early Valanginian – early Barremian. The dinocyst assemblages from the Helvetiafjellet Formation are significantly impoverished and are characterized by reworking, but collectively indicate a Barremian–Aptian age for this formation.

A summary is given of the lycophyte species as distributed in fifteen Euramerican coalfields during Asturian (Westphalian D) times. The datasets from the coalfields are analysed using unweighted pair group cluster analyses of Jaccard's Coefficients. Separate analyses were done on the full dataset (the full list of morphospecies) and on a more restricted dataset (only the morphospecies of vegetative organs). Three groupings of coalfields were resolved in the analyses. The two most clearly defined groupings represented the intramontane basin coalfields, and the coalfields of the lowland basins on the Variscan foreland where the lycophyte floras are well documented. The third grouping included those basins with less well-studied lycophyte floras, where the apparently low species diversity has undoubtedly affected the results. More work is needed on these poorly documented floras to produce a more rigorous phytogeographical analysis.

New data obtained from the study of the Kenyan and Tanzanian coastal basins establish a rifting period at the end of the Karoo sedimentation (Upper Triassic/Lower Jurassic), in the northeastern margin of Gondwanaland. The rifting period was followed by an erosive phase and then transgression of a Tethyan sea during the Middle Jurassic. This leads to a modification of the stratigraphic succession of the region and gives new datas about the nature of separation and drifting of Gondwanaland, the genesis of the proto-Indian ocean and the paleoposition of Madagascar

The Sicilian Channel is a broad and shallow shelf which is geologically part of the African Plate. Its NW sector (the Adventure Plateau), where water depths rarely exceed 100 m, is punctuated by several kilometre-sized morphological highs. These elevations, formed by both sedimentary and volcanic rocks, emerged around middle Holocene time or earlier when they constituted a large archipelago. High-resolution single-channel and multichannel seismic reflection profiles, along with stratigraphic and lithological information derived from exploration wells and rock samplings, are analysed to derive the shallow and deep structural setting of these banks and identify their geological nature. The sedimentary banks (Talbot, Ante-Talbot, Panope, Nereo and Pantelleria Vecchia), presently located at water depths 8–40 m, are composed of Miocene rocks severely deformed by a late Miocene compressional phase which produced the external sector of the Sicilian–Maghrebian thrust belt. Tortonian-aged rock samples from the Pantelleria Vecchia Bank represent patch reefs that have mostly formed on structural highs. Sedimentary analogies suggest that other sedimentary banks of the Adventure Plateau may have the same origin. Galatea, Anfitrite and Tetide represent submarine volcanic edifices emplaced on major extensional faults formed during early Pliocene – Quaternary continental rifting of the Sicilian Channel. The present-day morphology of the banks is the result of repeated phases of subaerial exposure and drowning, especially since the Last Glacial Maximum.

Late Cretaceous and Miocene collisions of the Arabian, Anatolian and Eurasian plates, as shown by widespread ophiolitic exposures along the suture, created favourable geological conditions for the formation of the surface and subsurface structures in the Gaziantep Basin, southeast Turkey. The late Cretaceous (Maastrichtian) emplacement of the Kocali–Karadut ophiolite complex induced subsidence in the northwestern zone of the Kastel Basin during the early Alpine Orogeny and influenced the structural evolution of the foreland area. The Dead Sea Fault, which originated in the Red Sea in Miocene time, propagated towards the northwest in the Suez Gulf and the north-northeast in southeast Turkey, and influenced the structural evolution of the Gaziantep Basin. These two major tectonic events produced many thrusts, thrust-related subsurface and surface anticlines, faults, fractures, flower structures and basaltic flows in the area. Geological and geophysical investigations indicate the existence of two important structural phases. The older structures were formed during the late Cretaceous movements, but they have been reactivated by latest Miocene tectonic activities with appearance of the Strands of the Dead Sea Fault in the sedimentary basin. The geothermal studies show also that, as a result of the Tertiary transgressions and volcanic activity, the northern and southern sectors of the Gaziantep Basin underwent differing subsidence and structural histories.

In this study, the petrology, zircon U–Pb ages, Lu–Hf isotopic compositions, whole-rock geochemistry and Sr–Nd isotopes for newly recognized low-Mg and high-Mg adakitic rocks from the North Altun orogenic belt were determined. The results will provide important insights for understanding the continuities of the North Qilian and North Altun orogenic belts during early Palaeozoic time. The low-Mg adakitic granitoids (445 to 439 Ma) are characterized by high SiO2 (69–70 wt %), low Mg no. (43–48) and low Cr and Ni contents. In contrast, the high-Mg adakitic granitoids (425 to 422 Ma) have relatively lower SiO2 (65–67 wt %), higher Mg no. (60–62) and higher Cr and Ni contents. The low-Mg adakitic rocks have high initial 87Sr/86Sr ratios (0.7073–0.7084), negative εNd(t) (−1.9 to −4.0) and εHf(t) values (−6.8 to −2.0), and old zircon Hf model ages (1.4–1.7 Ga). In contrast, the high-Mg adakitic rocks show lower initial 87Sr/86Sr ratios (0.7044–0.7057), higher εNd(t) (−0.7 to 3.1) and positive εHf(t) values (2.0 to 6.9), with younger zircon Hf model ages (0.9–1.2 Ga). These results suggest that the low-Mg adakitic rocks were probably generated by the partial melting of thickened crust, whereas the high-Mg adakitic rocks were derived from the anatexis of delaminated lower crust, which subsequently interacted with mantle magma upon ascent. The data obtained in this study provide significant information about the geological and tectonic processes after the closure of the Altun Ocean. The continent–continent collision and thickening probably occurred during 450–440 Ma with the formation of low-Mg adakitic rocks, and the transition of the tectonic regime from compression to extension probably occurred at 425–422 Ma with the formation of high-Mg adakitic rocks. The geochemical, geochronological and petrogenetic similarities between the North Altun and North Qilian adakitic rocks suggest that these two orogenic belts were subjected to similar tectonomagmatic processes during early Palaeozoic times.

In this paper the writer deals with certain mineralogical and textural features found in the Moine and Sub-Moine Series of western Scotland, viz. garnet-zoisite calc-silicate ribs, non-garnetiferous epidotic calcsilicate ribs, sutured (crenulate) quartz-mosaic, foliation oblique to folded bedding, and the presence of abundant yellow epidote and of spots of haematite. The garnet-zoisite calc-silicate ribs have been claimed by Dr. Richey and Professor Kennedy as diagnostic of parts of the Moine Series. For the non-garnetiferous epidotic calc-silicate ribs, which have not previously been described, the name “calc-silicate ribs of Arnipol type” is suggested. These ribs occur in adjacent groups of rocks that have been mapped with the Lower Striped Schists and the Lower Psammitic Group of the Moine and with the outermost psammitic zone of the Sub-Moine.

The presence of members of the Glossopteris flora in Antarctica was first attested by the material collected from Mount Buckley by Dr. Wilson and Lieut. Bowers on Capt. Scott's last expedition to the South Pole. and the now famous specimens were described by Professor A. C. Seward (1914). Traces of fossil plants in Antarctica, were, however, first discovered by Mr. H. T. Ferrar, a member of the National Antarctic Expedition, 1901–1904, and were briefly described by Arber (1907), who reported, on some specimens from the Ferrar Glacier, that “several of these show fair-sized carbonaceous impressions or markings, which in all probability are of vegetable origin”. The evidence presented by this unpromising material did not “permit of any opinion as to the botanical nature or affinities of the fossils themselves, nor of the geological age of the beds in which they occur” (Arber, 1907, p. 48). Professor Seward examined the specimens and agreed with this conclusion (1914, p. 2).