This paper records the succession which was encountered in a boring made during 1935 at Walsall, South Staffordshire. The site of the boring is precisely indicated in Text-fig. 1.

Chemical and mineralogical data are presented to demonstrate the overall similarity between granophyre and felsite from Rhum. However, although the compositions of the groundmasses of the two rock-types are very similar their characteristic textures are quite different. The felsitic texture is shown to be the result of devitrification of a glass, whilst the granophyric texture is attributed to the simultaneous crystallization of quartz and feldspar on the cotectic line in the system Ab–Or–SiO2–H2O. An explanation of the formation of the different textures is given in terms of the degree of super-cooling experienced by separate intrusions of the same magma in contrasted environments.

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 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).

The transition between the seemingly disparate Ediacaran and Cambrian faunas is both enigmatic and body-fossil poor. The Chapel Island Formation on the Burin Peninsula, Newfoundland, Canada, contains a rich diversity of ichnofossils, providing new insight into the nature of the Ediacaran–Cambrian transition and early Fortunian ecosystems. Five ichnoguilds are recognized within the Treptichnus pedum zone. Ichnologic data are analysed from an ecospace perspective, revealing a more protracted transition between Ediacaran and Cambrian ecosystems. Our analysis documents the appearance of limbs, vertical burrows and uncontroversial equilibrium structures, as well as the retention of ‘other’ feeding styles, such as microbial grazing and chemosynthesis.

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.

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.

The Troodos ophiolite in Cyprus and Baer–Bassit ophiolite in Syria together form part of the Tethyan ophiolite belt. They were generated in a supra-subduction zone setting in Late Cretaceous times. As with many of the ophiolite occurrences in this belt, the sequences are closely associated with tectonic ‘coloured mélange’ zones, which contain, among a variety of lithologies, metre- to kilometre-size blocks of metamorphic rocks. Precise 40Ar–39Ar laser step-heating experiments performed on four amphibolites from SW Cyprus and six from NW Syria, yield plateau ages ranging from 75.7±0.3 Ma to 88.9±0.8 Ma in Cyprus and 71.7±0.5 to 88.4±0.4 Ma in Syria. The older limits of these time spans are coeval with the age of the formation of the associated ophiolites. Unlike other metamorphic sole rocks which seem to form in relatively short time spans, these metamorphic rocks found in Cyprus and Syria are interpreted to have formed in Late Cretaceous times by accretion below the overriding Troodos and Baer–Bassit crust for a period of 15–18 Ma. The metamorphic complexes were exhumed by extension and crustal thinning associated with subduction roll-back and the rotation of the overriding plate until the cessation of subduction in Maastrichtian times. In Cyprus, the exhumed metamorphic complex was incorporated into an accretionary prism constructed primarily of the collapsed Mamonia passive margin sequence intercalated with rocks of the Troodos ophiolite during plate collision in the Maastrichtian. Concomitantly, in Syria, the Baer–Bassit ophiolite and subcreted metamorphic complex were emplaced onto the Arabian passive margin and fragmented into blocks and knockers, forming the Baer–Bassit mélange.

Early Permian anhydrite–gypsum strata in central Spitsbergen show deformation of sulphate nodules in dolostone (chicken-wire structure) to varying degrees from imbricate to extreme flattening and elongation. These shear zones often occur between undeformed layers of apparently similar strata.

The shear zones indicate a minimum displacement of between 0.5 and 1.5 km to the ENE of Zechstein and later strata over the Nordfjorden Block. Resultant folding and faulting over the Billefjorden Fault Zone represent an eastward manifestation of the Eocene West Spitsbergen Orogeny.

Two publications by Grabau, which will be treated in the following pages, have led to the ensuing considerations.

In his opinion world-wide advance and retreat of the sea are simply explained by vertical movements of the sea-level. About the possible cause of these movements he makes some very brief remarks, as we shall see later. It is, however, quite possible that the explanation must be sought in simultaneous but opposed movement of continents and sea-level. In trying to obtain an insight into the cause of these movements, rhythms of an entirely different sort come up for discussion, viz. phases of diastrophism and magmatic cycles. And then a further question presents itself: can these different phenomena be connected, and thus give an insight into certain rhythmical processes in the deeper parts of the earth ? I, personally, am convinced that we must answer this question in the affirmative. Stille, Joly, Holmes, and Bucher have reached a similar conclusion by different ways. Meanwhile, the following pages are only intended to shed some light on the different aspects of the problem, and I shall restrict myself to outlining the questions that demand further study.

The recent discussion on the origin of the Himalaya, initiated by Colonel S. G. Burrard in his paper “On the Origin of the Himalaya Mountains”, has centred in the theories of isostasy and mountain compensation advocated by the Rev. O. Fisher and Mr. J. F. Hayford.

In his latest contribution to the subject Colonel Burrard states very clearly the problem of isostasy now requiring solution—

“Continents and mountains have been found to be compensated by underlying deficiencies of density; how has this condition resembling hydrostatic equilibrium arisen upon a solid globe of rock?”

In a recent paper I have advanced reasons for believing in the existence in the earth's crust at a certain depth, at present unknown, of a highly garnetiferous shell of rock, for which the name infra-plutonic zone or shell is suggested. This zone is situated at such a depth that pressure becomes a dominant factor in mineral transformations, the accompanying high temperature ensuring a sufficient degree of molecular mobility. It is suggested that under the influence of these high pressures (and temperatures) reactions will ensue between the various ferromagnesian silicates—micas, amphiboles, pyroxenes, olivines—and anorthite felspar, with the formation of garnet as a characteristic mineral: the reason assigned is that a reduction of volume accompanied by an absorption of heat is thereby effected, it being accepted that the garnet-forming reactions are endothermic.

If one can accept the philosophical necessity for the existence of this infra-plutonic shell, then some theory of isostasy seems logically to follow, with the garnetiferous plastic-solid shell as the cushion upon which the isostatic adjustments of the earth's crust have their foundation.

A detailed vitrinite reflectivity study has been made through the Cretaceous sedimentary rocks of northwest James Ross Island, Antarctica. The results show that a progressive increase in reflectivity does not occur with depth and that values (0.45 %) from the base of the succession are lower than expected for the sequence as described by previous authors. Using a synthesis of sedimentological and stratigraphic information, the sequence is reinterpreted as an apparent monoclinal syncline, strongly influenced by syndepositional tectonics, with a thickness appreciably less than previously described.

Granodiorite intrusions in Jamaica were assigned by early workers to various ages from Pre-Cambrian to late Tertiary. Recent surveys have shown that the granodiorite intrudes Maestrichtian sediments and has provided material for pebbles in an Eocene conglomerate. Its age is therefore very late Cretaceous or very early Tertiary. Radio-metric determinations using Potassium/Argon; Rubidium/Strontium and isotopic lead methods suggest an age of 65 ± 5 million years.

A virtually complete Jurassic sequence recently drilled in north Lincolnshire is considered in a regional context. Liassic thicknesses and facies are largely unexceptional. The Frodingham and Pecten Ironstones are relatively thin and sandy, but the Marlstone Rock Bed is thicker and more ferruginous than elsewhere in the region. The Inferior Oolite is exceptionally thick and exhibits strong deltaic influence; equivalents of the Gristhorpe Member and Scarborough Formation of Yorkshire may be present. The Great Oolite was deposited in coastal-lacustrine-deltaic environments, more proximal than to the south or east. Thin Kellaways Clay separates the argillaceous Cornbrash from the Kellaways Sand. The organic-rich Lower Oxford Clay is thin owing to a basal non-sequence whilst the Upper Oxford Clay is condensed and less organic than in the East Midlands. The regressive West Walton Beds are followed by very thick Ampthill and Kimmeridge Clay sections beneath the Spilsby Sandstone. Regional thickness and facies analysis records the behaviour of the Market Weighton Block and reveals the influence of the Pennine High as both a positive tectonic feature and an occasionally active sediment source.

Homa Mountain is a well developed ijolite/carbonatite complex of Miocene to Quaternary age. Late stage olivine melilitite occurs as a satellite plug, parts of which show strong deuteric alteration to carbonate resulting in complete pseudomorphing of the melilite.

A second satellite centre exposes a grey carbonate tuff and accompanying dykes, all of which exhibit relic textures after an elongate, rectangular mineral also formerly believed to be melilite. Comparison with other recently described occurrences indicates however that the second centre erupted alkali-carbonatite and that the chief mineral originally present was nyerereite (Na2Ca(CO3)2). The field relationships and petrographic characters of both rock types are described and criteria are given which permit distinction between carbonated melilite and calcitized nyerereite. It is concluded that olivine melilitite and alkalicarbonatite are closely related in space and time.

In 1957, Hudson, Eames & Wilkins proposed the name of Hammar Formation for a series of sands and silts below the surface alluvium of the Mesopotamian Plains near Basrah, Iraq, which yielded a marine molluscan fauna of Holocene age. This paper shows that deposits yielding a very similar molluscan fauna are present at shallow depths at Amarah and Qurmat Ali, and lists the numerous foraminifera recovered from these deposits. Marine or brackish water conditions are thus shown to have prevailed in recent times over a distance of at least 250 km NW of the present head of the Persian Gulf.

The superfamily Lichacea is here considered to include two families : the Lichidae, composed of four subfamilies and twenty-four genera, and the Lichakephalidae, comprising only one species. Reed's interpretation of the glabellar and occipital lobes in the Lichidae is considered to be correct; the definition and degree of fusion of these lobes is the main criterion of generic discrimination. Hypostomal features are of assistance in defining subfamilies. The characters of the pygidium are constant in some genera, but unstable in others. The Lichinae and Homolichinae, stratigraphically the oldest subfamilies of the Lichidae, are chiefly European in occurrence during the Ordovician period. The Tetralichinae and the Ceratarginae occur earlier in North America than in Europe. Lichakephalus occurs in Lower Tremadoc beds of Bavaria.

A ‘reg’-type palaeosol occurs at the top of the Lower Triassic Budleigh Salterton Pebble Beds at Budleigh Salterton, south Devon. Its morphology supports the idea that such soils form by the introduction of wind blown fines below a surface stone layer by a process of wetting–drying and crack formation. The degree of profile development indicates a prolonged period of pedogenesis, corresponding to a major stratigraphic break. The palaeosol formed under arid conditions, and represents a change in climate during Scythian times from a semi-arid to arid regime.

Kronprins Christian Land lies at the northernmost limit of the East Greenland Caledonides, and may be divided into four main tracts: foreland, parautochthon, thin-skinned thrust sheets containing Neoproterozoic sediments, and thick-skinned thrust sheets of crystalline basement. The eastern part of the foreland and the parautochthon are composed of Ordovician–Silurian shelf carbonates overlain by Llandovery–lower Wenlock turbidites deposited at the southern margin of the Franklinian Basin. Deformation of the parautochthon occurred beneath a major detachment, the Vandredalen thrust, with Neoproterozoic sediments of the Rivieradal Group lying in the hanging wall. The Rivieradal Group was deposited in an E-facing half-graben and was displaced westwards across its rift shoulders during Caledonian thrusting. Extensive sampling for conodonts has been carried out within the Lower Palaeozoic rocks of the foreland and parautochthon in order to increase the precision of structural interpretations and to provide data on maximum burial temperature and, in turn, the thickness of overburden. In contrast to earlier studies, conodont colour alteration indices (CAI) show a gradual and continuous increase from CAI 3 in the eastern part of the foreland to CAI 5+ in the easternmost parts of the parautochthon. The isopleths are not disrupted or truncated by thrusting, as previously suspected, indicating that the heating is not attributable to pre-thrusting stratigraphic overburden. Furthermore, considerations of the regional geology indicate that there was no significant accumulation of sedimentary overburden in post-Caledonian time; the predominant component is thus considered to be loading by thrust sheets. Modelling of the overburden thickness suggests that, prior to erosion, it increased from 3.9 km (CAI 3) in the easternmost foreland to a maximum of 12.5 km beneath the Vandredalen thrust sheet in the easternmost part of the area, providing constraints for restoring cross-sections across the orogen.