The proposed correlation of Lower Old Red Sandstone dacitic ignimbrites between the Northern Midland Valley and Grampian terranes of central Scotland has been investigated in a combined palaeomagnetic and geochemical study. Statistically indistinguishable late Silurian palaeolatitudes (Grampian terrane 27.0° S±3.5°; Northern Midland Valley terrane 22.9° S± 1.8°), comparable remagnetization histories, a shared ‘normal’ polarity for the primary magnetization and equivalent gyroremanence acquisition, favour correlation across the Highland Boundary Fault. Similar chemistry for biotite phenocrysts further corroborates correlation which was initially made on the basis of a similar field appearance and petrography.

This correlation, together with evidence from provenance studies, suggests that the separation of the Northern Midland Valley and Grampian terranes inferred for the Ordovician period was largely removed by late Silurian times, with scope for relative displacements of the order of only tens of kilometres after Lower Old Red Sandstone deposition.

A number of garnetiferous minor intrusions have been mapped within the Borrowdale Volcanic Group. They underlie garnetiferous extrusive volcanic rocks which occur toward the top of a sequence of ignimbrite and lava – the Airy's Bridge Formation – which is the product of a major caldera-forming eruptive episode. Garnet and whole-rock geochemistry indicate that most of the intrusions are indistinguishable from garnetiferous dacite forming the final eruptive unit of the Airy's Bridge Formation: a co-magmatic link is therefore postulated. One of the intrusions, which intrudes the Airy's Bridge Formation, is distinct and may be related to the later Eskdale pluton.

It is suggested that following the emplacement of ignimbrites forming the basal half of the Airy's Bridge Formation, caldera collapse partially sealed a fissure-conduit system and degassed, garnet-bearing magma was intruded as dykes and sills and locally extruded as a post-explosive lava dome. It is also postulated that garnet crystallized in a high-level magma chamber (P < 3 kb) and that reverse chemical zoning was due to growth while sinking through compositionally stratified magma.

Last year, while the Port Elizabeth Brick and Tile Company were quarrying a clayey rock at Despatch, near Uitenhage, a number of bones were discovered in the rock. Though the discovery created some little interest, no one seems to have appreciated the scientific value of the find, and large numbers of the bones were made into bricks. A few fragments of vertebræ and ribs have been collected by the Port Elizabeth Museum, and recently an attempt has been made to rescue some more of the bones that still remain in the rock. So far a number of very imperfect fragments of vertebræ—cervical, dorsal, and caudal—a fairly good femur, an imperfect scapula, portions of many ribs, and an ungual phalanx, have been discovered. The examination of these remain leaves no doubt that the skeleton is that of an Opisthoeælian Dinosaur of moderate size.

Leaf compression fossils are abundant within the lower Cretaceous part of the Fossil Bluff Formation in southern Alexander Island, Antarctica. They occur in lacustrine laminated siltstones with a high volcaniclastic component. During zeolite facies metamorphism of the rocks, breakdown of clay minerals, volcanic glass and calcic plagioclase generated new mineral phases. The growth of these minerals was concentrated within and around leaves: finely disseminated oxide of titanium crystallized within the organic material, a thin film of chlorite was precipitated around leaves and silica, calcite and laumontite grew disruptively between leaf cuticles. Despite relatively low levels of organic maturation the structure of the leaf cuticles was destroyed and the only details which survived were those preserved as impressions in the chorite film.

The Chitradurga greenstone succession of south India comprises a thick pile (~ 10 km) of late Archaean volcanic flows and terrigenous clastic sediments, metamorphosed from greenschist to low-grade amphilobite facies. An older near-shore sedimentary sequence of cratonic affiliation and an off-shore bimodal volcanic sequence were deposited contemporaneously on a gneissic basement. The volcanics are metasomatically altered, and major, minor and trace element data fail to discriminate the metavolcanics in terms of modern plate settings. A younger turbidite sequence of coarser elastics covered the older deposits without any apparent tectonic or erosional break. All the rocks of the succession display evidence of similar deformation, prior to invasion by younger granites (~ 2.5 Ga)in a late syn-kinematic phase.

This suggests that initially a simple flat-lying downwarp in a continental crust served as the passive receptacle of the platform-type sediments, and also witnessed volcanism along extensional faulting. This phase of the basin was not associated with any compressive deformation. Subsidence of the Chitradurga basin by the denser volcanics and uplift in the gneissic borderlands provided the infrastructure for subsequent development of the younger turbidite sequence covering the still virtually undeformed older deposits. A compressive orogeny, accompanied by granitic intrusion (~ 2.5Ga) in a late kinematic phase, ultimately deformed and uplifted the basin-fill during the declining phase of basinal activity.

There is no evidence in the belt to suggest that the plate-tectonic (Wilson cycle) processes, pending a terminal orogeny, were operative during evaluation of the Chitradurga basin.

In the following pages I have endeavoured to give an interpretation, not only of the appearance of ice ages, but also of the greater changes of climate registered in the geological record. In view of the importance ascribed in this discussion to relief, I have named the theory the relief hypothesis.

Although spilite as a rock name has been in use for nearly a hundred years, there are few rocks, probably none of equal importance, so incompletely understood. Introduced in 1827 by Brongniart, “spilite” was first used officially in this country by Flett when describing the pillow-lavas of South Devon (Plymouth and Liskeard Memoir, 1907), and has now completely replaced the indefinite terms “greenstone” and “epidiorite”, by which these lavas were formerly known. It is only quite recently that the importance of spilite has been properly appreciated. The progress of research has shown that at several different geological periods lavas of spilitic type have been almost completely dominant in Britain. Typical spilites and keratophyres were extruded in Pre-Cambrian times over a very extensive area, remnants of the flows being preserved in Argyllshire (Tayvallich and Loch Awe), and in Anglesey, localities which must have been far removed from one another at that time. Throughout Ordovician times the basic lavas were almost without exception spilites or closely allied types. The best known examples of spilites in Britain are those occurring abundantly in the Devonian and lower part of the Carboniferous rocks of South-West England, so ably described by Dewey and Flett, to whom most of our knowledge of these rocks is due. To deny the important rôle of spilite in the history of igneous activity in this country is no mere difference of opinion, but a denial of fact. Yet there are many who, with the American geologists, deny not only the importance, but; even the existences of the rock. The other extreme of opinion is found in those who see in the spilitic rocks a series whose petrogenesis presents problems of more than usual interest and which they have elevated to occupy a position comparable in importance with the better known calcic and alkalic suites.

The following is a brief account of some minute Crinoid calyces, which appear to have been hitherto undescribed, sent me by Dr. Arthur Rowe, who obtained them from the Micraster cortestudinarium zone of the Upper Chalk.

The Lower Carboniferous rocks of the Craven Lowlands are predominantly fine-grained dark argillaceous limestones and calcareous mudstones and shales with a fauna of Zaphrentid or Caninoid phase. At various horizons and along various belts these argillaceous rocks are replaced by reef limestones and the associated crinoidal limestones, reef sands, and “calcaire grumeleux”. These lisnestones usually contain a specialized reef fauna or more rarely the standard coral-brachiopod fauna.

In northern Turkey, the Intra-Pontide suture zone represents one of the first-order tectonic structures located between the Istanbul–Zonguldak and the Sakarya continental terranes. It consists of an E–W-trending assemblage of deformed and variably metamorphosed tectonic units, including sedimentary rocks and ophiolites derived from a Neo-Tethyan oceanic basin, known as the Intra-Pontide oceanic basin. One of these units is represented by the Daday Unit that consists of a block-in-matrix assemblage derived from supra-subduction oceanic crust and related deep-sea sedimentary cover of Middle Jurassic age. This setting was acquired during Late Jurassic time by tectonic underplating at a depth of 35–42 km associated with blueschist-facies metamorphism (D1 phase). The following D2, D3 and D4 phases produced the exhumation of the Daday Unit up to shallower structural levels in a time span running from the Albian to late Paleocene. The high geothermal gradient detected during the D2 phase indicates that the Daday Unit was exhumed during a continent–arc collisional setting. The tectonic structures of the Intra-Pontide suture zone, resulting from the previously described tectonic history, are unconformably sealed by the upper Paleocene – Eocene deposits. This tectonic setting was intensely reworked by the activity of the North Anatolian Fault Zone, producing the present-day geometrical relationships of the Intra-Pontide suture zone of the Central Pontides.

Here we present a detailed accounting of organic microfossils from late Ediacaran sediments of Finland, from the island of Hailuoto (northwest Finnish coast), and the Saarijärvi meteorite impact structure (~170 km northeast of Hailuoto, mainland Finland). Fossils were recovered from fine-grained thermally immature mudstones and siltstones and are preserved in exquisite detail. The majority of recovered forms are sourced from filamentous prokaryotic and protistan-grade organisms forming interwoven microbial mats. Flattened Nostoc-ball-like masses of bundled Siphonophycus filaments are abundant, alongside Rugosoopsis and Palaeolyngbya of probable cyanobacterial origin. Acritarchs include Chuaria, Leiosphaeridia, Symplassosphaeridium and Synsphaeridium. Significantly, rare spine-shaped sclerites of bilaterian origin were recovered, providing new evidence for a nascent bilaterian fauna in the terminal Ediacaran. These findings offer a direct body-fossil insight into Ediacaran mat-forming microbial communities, and demonstrate that alongside trace fossils, detection of a bilaterian fauna prior to the Cambrian might also be sought among the emerging record of small carbonaceous fossils (SCFs).

Investigations of the March Gravels of Northam Pit, Eye, Cambridgeshire, have provided previously undescribed molluscan, ostracod and foraminiferal faunas together with pollen spectra, which enable a detailed palaeoenvironmental synthesis to be developed. The sediments were laid down in brackish-water conditions and a temperate environment, during a Late Pleistocene temperate stage.

The aim of this study is to describe the biostratigraphic, chronostratigraphic and ecostratigraphic relationships of the Neogene sequence in the Adana Basin. The Adana Basin is located in southern Turkey, and bordered by the Tauride Orogenic Belt to the north, the Amanos Mountains to the east, the Mediterranean coast to the south and the Ecemiş Fault Zone to the west. From base to top, the Neogene sequence consists of the Gildirli Formation (continental redbeds), the shallow marine Kaplankaya Formation, the reefal limestones of the Karaisalı Formation, the shales of the Güvenç Formation (slope to deep marine), a thick submarine fan complex (Cingöz Formation), the shallow marine and fluvio-deltaic Kuzgun Formation and the shallow marine lagoonal–continental Handere Formation. The planktonic foraminiferal biozones identified within the Neogene sequence of the Adana Basin are Globigerinoides trilobus and Praeorbulina glomerosa curva (Burdigalian), Globorotalia fohsi peripheroronda/Orbulina suturalis (Langhian), and Globorotalia mayeri (Serravallian). The Late Tortonian is characterized by the first occurrence of Globorotalia suterae. There are no planktonic foraminiferal zones in the Messinian, but this level may be correlated with a non-distinctive zone in the Mediterranean region. The Pliocene is represented by the Sphaeroidinellopsis Acme Zone.

In the year 1913 the author formed the intention of carrying out a comprehensive investigation of the mineral composition of the Lower Greensand strata of England, in order to ascertain whether any definite conclusions could be drawn as to the sources of the material and the geographical conditions that existed while the deposits were being formed. A large number of specimens were collected along the out crop from the Wash to the borders of Buckinghamshire and examined by the usual laboratory methods. This work was interrupted by the outbreak of war, and on returning to Cambridge after an absence of nearly four years on Government service circumstances proved to be unfavourable to a continuance of the work on the scale originally contemplated. The district already dealt with forms in itself a fairly well-defined unit, and it was decided to publish an account of the results already attained, in the hope that they may be of service to future workers in this interesting field of petrological and stratigraphical research.

An unusual fayalite-bearing quartz-monzonite occurs around Bauchi in Northern Nigeria and is distinguished from the high-level fayalite granites of the Newer Granites ring complexes by the presence of a linear structure conformable with those in the surrounding rocks, the gradational nature of its contacts, the extreme coarseness of its mineral constituents and the abundance of myrmekite. It is similar to them in its distinctive green colour and in the high FeO: Fe2O3 ratio. The rock is believed to be definitely older than the rocks of the ring-dyke complexes.

The Upper Silurian rocks of Lesmahago, Lanarkshire, have long been known to contain Arthropod remains. In the Kelvin-grove Museum, Glasgow, are a number of curious forms from the Logan Water Lesmahago, which Professor McNair was good enough to allow me to examine. In the hope of solving some problems presented by them, I obtained, through the kindness of the Keeper of the Geological Department of the British Museum, the loan of a specimen from the same locality, which forms the subject of this note. Instead, however, of solving any difficulties, the specimen presented a new problem.

Marked differences in relative abundance of right and left valves of certain recent lamellibranchs are recorded in collections made along beaches of eastern Trinidad, and a possible explanation is discussed.

For many years the breccia of Western Cumberland has been known locally as “ The Conglomerate ”, under which name it figures largely in hundreds of records of borings put down in search of haematite or coal. Since, however, its components consist in general of angular and subangular rather than rounded fragments, the term “ conglomerate ” is misleading; hence the deposit is here referred to as “ Brockram ” (broken rock), a descriptive lithological term applied to rocks of similar origin in the Vale of Eden and of definite significance to British geologists.

The Lower Hecla Hpek rocks of Ny Friesland are described petrographically, and evidence is presented relating to some granitic rocks in this group whose mode of origin is uncertain.