We present the first record of Holocene and Pleistocene environmental change derived from the chemical and stable-isotope composition of a tropical cave guano sequence from Makangit Cave in northern Palawan (Philippines). The 180 cm sequence of guano, derived predominantly from insectivorous bats and birds, consists of two distinct units. An upper section of reddish-brown oxidised guano to 110 cm was deposited since the mid-Holocene while a lower section of black, reduced guano was deposited through the Last Glacial Maximum (LGM) to >30 000 BP. Carbon-isotope (δ13C) values in guano deposited during the LGM are as high as −13·5‰ indicating that a C4-dominated grassland existed in the area around the cave at this time. Guano δ13C values of − 25‰ to − 28‰ suggest that this open vegetation was replaced by C3-dominated closed tropical forest, similar to that of the present, by the mid-Holocene. The results suggest that the climate of northern Palawan was substantially drier at the LGM than is currently the case.

1. The presence of heat may be recognised in every natural object; and there is scarcely an operation in nature which is not more or less affected by its all-pervading influence. An evolution and subsequent absorption of heat generally give rise to a variety of effects; among which may be enumerated, chemical combinations or decompositions; the fusion of solid substances; the vaporisation of solids or liquids; alterations in the dimensions of bodies, or in the statical pressure by which their dimensions may be modified; mechanical resistance overcome; electrical currents generated. In many of the actual phenomena of nature, several or all of these effects are produced together; and their complication will, if we attempt to trace the agency of heat in producing any individual effect, give rise to much perplexity. It will, therefore, be desirable, in laying the foundation of a physical theory of any of the effects of heat, to discover or to imagine phenomena free from all such complication, and depending on a definite thermal agency; in which the relation between the cause and effect, traced through the medium of certain simple operations, may be clearly appreciated. Thus it is that Carnot, in accordance with the strictest principles of philosophy, enters upon the investigation of the theory of the motive power of heat.

The Ammonoids described in the present paper were placed first of all, for study, in the hands of Mr J. M. Wordie, whose departure, however, as geologist with Sir E. Shackleton's Antarctic Expedition prevented the completion of the work. A preliminary list of identifications by Mr Wordie included a number of forms of “Schloenbachia” especially “S.” inflata, J. Sowerby sp., this form alone being quoted from ten localities. Professor Gregory, in his “Contributions to the Geology of Benguella,” * referred to these identifications, and in his correlation-table classed the beds with “Schloenbachia inflata” as “Vraconnian,” following the prevailing custom. It may be well, however, to remark here already that A. inflatus, J. Sowerby, will be shown to be an exclusively Albian, and not even uppermost Albian, form, and that there is no evidence of any Cenomanian admixture in the typically Albian fauna of the so-called “zone of A. inflatus” in Angola, so that the term Vraconnian is here rejected. Moreover, Renevier's “Vraconnian” was meant for post-inflata beds, and, in the writer's opinion, Sowerby's species is not represented at all in the Angola collection.

Phacopid trilobites, unlike most trilobites, lack functionally articulated libregenae. This distinction presumably dictated ecdysial strategies which were fundamentally different from those forms with sutured cephala. Phacops rana (Green) and Greenops boothi (Green) from the Middle Devonian Hamilton Group (New York) are preserved in circumstances which illustrate certain aspects of their moulting behaviour. Undisturbed exuviae display five different moult patterns; these suggest two basic modes of exuviation in phacopid trilobites (Body-upright and Body Inversion Moult Procedures).

Certain Hamilton beds yield clusters of Phacops comprising complete and/or moulted remains. Complete trilobites in body clusters display varied orientations which, when considered in conjunction with exuvial patterns in moult clusters, suggest ecdysial procedures that involved body inversion and erratic tergal contractions (Body Inversion Moult Procedures). Ensembles where in thoracopygidia are upright and outstretched indicate hyperextension of the thorax and disarticulation of the cephalo-thoracic suture (Body-upright Moult Procedures). Phacops moult ensembles are characterised by inverted and tightly recurved thoracopygidia, whereas Greenops ensembles comprise outstretched, usually upright thoracopygidia with cephala that are frequently upright. Classic ‘Salterian’ patterns are uncommon in Phacops rana and have not been recognised in Greenops boothi. Variations in moult procedure are attributed to differences in functional morphology and substrate consistency.

In 1925 Professor A. E. Trueman handed to the writer a copy of Professor Bertrand's paper, “Les Zones Végétales du Terrain Houiller du Nord de la France” (1914, p. 208), with the suggestion that it would be interesting to find out whether the succession of plants in South Wales is similar to that of the North of France, and to determine whether Bertrand's zones can be applied to the Coal Measures of South Wales. Since that time every opportunity has been taken to collect fossil plants from known horizons in South Wales and other coalfields. In addition, specimens have been examined in all the important museums and private collections, and in particular in the collections of the late Dr R. Kidston, which are now preserved in the Museum of Practical Geology.

U-Pb zircon geochronology of Mesoproterozoic (Subjotnian) rapakivi complexes in central Sweden yields: 1526 ± 3 Ma (Mullnäset), 1524 ± 3 Ma (Mårdsjö), 1520 ± 3 Ma (Nordsjö) and 1497 ± 6 Ma (Rödön). Together with complexes further S in Sweden, they constitute the westernmost, youngest (1·53−1·47 Ga) belt of rapakivi magmatism in the Fennoscandian shield.

The low initial εNd values (−8·9 to −4·8) of all studied Subjotnian basic, intermediate and silicic rocks, require an input from an old (Archaean) low-radiogenic source component, as evidence for Palaeoproterozoic protoliths in the age range 2·5−2·1 Ga is lacking in this region. Crustal, early Svecofennian + Archaean (roughly 30−40%) sources are suggested for the Subjotnian A-type granites and syenites, where the granites derive from undepleted, granodioritic, and the syenites from monzodioritic (±depleted crustal) protoliths. The basic rocks originate from a depleted mantle acquiring the enriched Nd isotopic signatures during interaction with an Archaean lower crust (20−40%), largely depleted after rapakivi melt extraction. Pb isotope data from feldspars (207Pb/204Pb to 15·018−15·542) support the presence of Archaean components in the magmas.

The results indicate that an Archaean basement is underlying relatively wide areas of Svecofennian formations in central Sweden. This old basement section was most likely rifted off the Archaean craton in the NE in Palaeoproterozoic times.

A structural profile has been constructed for part of the Caledonian fold belt from a map of the Dalradian rocks of the Loch Awe District of Argyllshire. The profile includes the Loch Awe Syncline (Bailey 1913) and the root to the Tay Nappe (Shackleton 1958). The Loch Awe Syncline is shown to be a compound syncline of F1 age, congruent with the Tay Nappe. The F1 structures are accompanied by a penetrative deformation and modified by secondary structures. The stratigraphic succession, which includes the Upper Dalradian and part of the Middle Dalradian, has been reconstructed from the profiles and is shown to have originally been about 10 km thick. The prominent features are the development of a basin to the south-east of the present area in the Late Pre-Cambrian and the extrusion of a 2 km thick basic submarine lava pile in Lower Cambrian times. A subsequent basic submarine lava sequence was extruded in Late Lower Cambrian or Middle Cambrian time and represents the topmos lithostratigraphic group yet recorded from the Dalradian of S.W. Argyll.

Morphology and ontogenetic changes in the skull and hyobranchium of the Permo-Carboniferous temnospondyl Archegosaurus decheni from the Saar–Nahe Basin (SW Germany) are described in detail, based on 181 skulls ranging from 18 to 279 mm in length. Three-dimensional skull reconstructions including the palate of different growth stages are provided. The extremely elongate choanae and up to four median symphyseal teeth are unique to A. decheni. Among neurocranial elements, the exoccipital is well ossified and forms the paroccipital process as in stereospondyls. The shaft of the stapes which projects into the squamosal embayment grows with positive allometry and possesses a distinct lateral process. The basibranchial is well ossified in adults and exhibits a complex, spoon-like morphology. Small larvae were euryphagous and used non-directed suction and jaw prehension during prey capture. Larger larvae and adults were mainly ichthyophagous, as is indicated by the increasingly elongated snout, differentiation of marginal teeth, and nutrition remains. After a prolonged larval period, juvenile and adult A. decheni remained in the aquatic habitat, as suggested by the presence of lateral line sulci, the ‘aquatic type’ of septomaxilla and choana, and the absence of a nasolacrimal duct.

Once thought to be devoid of life, the Antarctic Ice Sheet is now known to be a dynamic reservoir of organic carbon and metabolically active microbial cells. At the ice-bed interface, subglacial lake and sedimentary environments support low diversity microbial populations, adapted to perennial cold, anoxia and lack of light. The dynamic exchange of water between these shallow environments conveys meltwaters and associated sediments into the coastal ocean. This, together with the release of iceberg-rafted debris to more distal coastal environments, could be important for sustaining primary productivity in the iron-limited Southern Ocean, via the release of associated nutrients and bioavailable iron. We estimate the magnitude and review the wider impacts of the potential export of nutrients (N, P, C, Si and bioavailable Fe) dissolved and associated with suspended sediments in Antarctic runoff and entombed in iceberg rafted debris. Located beneath subglacial lakes and the subglacial till complex are deep sedimentary basins up to 14 km thick, located largely around the Antarctic periphery. These sedimentary basins are largely hydrologically decoupled from shallower lake and till environments by the presence of highly consolidated sediments which limit the penetration of glacial meltwaters to depth. They provide extensive habitats for sustained microbial activity over Ma timescales, and are likely to be a focal point for the anaerobic cycling of organic carbon and other elements in the deep sub-surface. Organic carbon buried in these basins during ice sheet formation is thought to be microbially cycled to methane gas, and the methane largely stored as hydrate within sediments, stabilised by the high pressure/low temperature conditions. We conclude that the export of nutrients and biogenic gases from deep and shallow subglacial Antarctic environments designates Antarctica as a potentially important component of the Earth's carbon cycle, and highlight the importance of evaluating these potential impacts further via global and regional-scale biogeochemical modelling.

The term “Hebrides” is of unknown origin. Some authorities suggest that it meant “the islands of Brude,” called after the names of several Pictish kings. There seems also to be considerable uncertainty about the name “Lewis.” Some derive it from “Leog,” a marsh. Macculloch traced it to “Loda,” a Scandinavian deity. The name has appeared in various forms, the earliest of which appears to be “Leodus.” Another suggestion is that it may be after “Leutha,” the last of the three Pictish kings who ruled in Orkney (Mackenzie, 1903, pp. xxxvi-xxxviii).

The Chimborazo (6,310 m)–Carihuairazo (5,102 m) massif is one of the largest ice-capped central volcanic complexes in the northern Andes. Combined evidence from volcanic and glacial landforms and sediments suggests cyclical evolution during the Pleistocene. Effusive eruptions of mixed high-silica andesite (SiO2%wt c. 60) predominated and built the bulk of the edifice. Explosive activity developed as the parental magma evolved to dacite-rhyolite (SiO2%wt 64–74), culminating with cone collapse and large-scale debris avalanching. Post-collapse activity evolved from the production of high-silica andesite to terminate with monogenetic eruptions of basic andesite (SiO2%wt 54–56) from flank fissures. The last eruption occurred before 11,000 yBP.

The interstratification of volcanic and glacial deposits shows that glaciers expanded and contracted several times during the later Pleistocene, while the volcanic edifices were evolving. Glaciers expanded to altitudinal limits of 3,400–3,600 m during the early last glaciation and reached similar limits sometime after 33,000 yBP; an intervening interstadial interval lasted for 10,000 y. By 20,000–18,000 yBP, glaciers receded slightly because of decreased precipitation, but later readvances culiminated at 12,000–10,000 yBP and during the last 5,000 y. Glacier reconstruction and estimation of former equilibrium line altitudes suggest that the mean annual temperatures during the full glacial, late-glacial and Neoglaciation intervals were lower than now by c. 5–6°C, 2–3°C and 1°C, respectively, but these may be underestimates because of the assumption that precipitation was constant.

The genesis of subduction-related magmas in the Andean region of South America and the Antarctic Peninsula is considered in relation to the Palaeozoic to Cenozoic granitoids belts which are thought to parallel palaeo-coastlines. Their Sr-Nd isotope systematics show a wide range of initial compositions (87Sr/86Sr0 0·7038 to >0·710; εNd, +4 to –10) requiring material input from both depleted mantle and continental crust. In local transects there are consistent trends with time of emplacement, from enriched (crustal) to depleted (mantle) sources, regardless of the sense of migration of magmatism (towards or away from the continent). These trends represent mixing between mantle-derived material and anatectic melts of the lower crust: in each case the crustal end-member reflects the age and isotopic composition of the local deep crustal basement (Precambrian in the easternmost Andes, Palaeozoic in the W and in the Antarctic Peninsula). The depleted end-member could be derived by melting within the subducted oceanic crust, the overlying mantle or previously crystallised mafic underplating. One of the most important factors controlling the mixing process is the angle of subduction, resulting in magma generation under variable tectonic conditions.

Re-investigation of species-rich late Tournaisian floras at Oxroad Bay reveals eight plant-bearing exposures that represent four distinct stratigraphic levels. The allochthonous megafossil assemblages vary in degrees of disarticulation, modes of preservation and taxonomic composition. Within-site stratigraphic distributions are presented for 43 anatomically-preserved organ-species; of these, 12 are new to science, 18 have not previously been recorded at the locality, 21 are illustrated from the locality for the first time and 19 are currently considered endemic. Another six have been recorded in error from unprovenanced water-worn blocks. Nineteen adpressed organ-species are also described. Methods and concepts of whole-plant reconstruction are reviewed. At least 11 whole-plant species occur at Oxroad Bay. The lycopsids comprise an enigmatic plant with an Asteroxylon-like stele and two morphologically- and ecologically-distinct species of Oxroadia. A new species of Protocalamites demonstrates the earliest evidence of heterospory and tuberoid stem-bases in the sphenopsid clade. Cladoxylon and Stauropteris represent the pteropsids. At least five lyginopterid pteridosperm species are present. They include both trees (Eristophyton, Bilignea) and shrubs/pseudoherbs (e.g. Tetrastichia and the Triradioxylon–Calathopteris–Oxroadopteris–‘Tristichia’ plexus), suggesting a range of life strategies. Their diversity has complicated attempts to reconstruct whole-plants, though attachment is demonstrated between several ovules and cupules, and several ovules and pollen-organs are correlated using shared microspores. Elements of particular evolutionary significance include the ‘megacupule’ Calathospermum and a structurally similar pollen-organ aggregate, a bisexual Pullaritheca cupule, and a complete ontogenetic sequence of Hydrasperma ovules. Comparable Dinantian floras are reviewed.

During the last few years the distribution of the macrofauna, and to a less extent the microfauna, of the intertidal soils of the shores of Britain has received considerable attention and the principle that the species show a zonation with maximum densities at certain levels is now well established. The extensive studies of Elmhirst (1931) and of Stephen (1928, 1929, and 1930) on the fauna of the sandy and muddy areas of numerous Scottish bays has laid the foundation for much further work in this area. Pirrie, Bruce, and Moore (1932) have described the zonation of the fauna in the intertidal sand of Port Erin bay. Alexander, Southgate, and Bassindale (1935) refer to the fauna of the sand at the mouth of the River Tees, but mainly from the point of view of comparison with the fauna of the estuary. Crawford (1937 a and b) gives notes on the distribution and habits of certain intertidal species in sandy bays and estuaries in west England and south Wales. Rees (1939) has surveyed in outline, as part of a study of the interstitial sand copepods, the macrofauna of some sandy bays in north Donegal. Spooner and Moore (1940) have given a detailed description of the zonation of the species in the estuarine muds of the Tamar. Apart from the above, reference must be made to two intensive studies on the soil fauna of the eastern shores of the North Sea, namely, that of Thamdrup (1935) on Danish shores and of Wohlenberg (1937) on certain bays on the island of Sylt. A general discussion of the ecological problems of sand, mud, and algal environments is given by Remane (1933), based on the macrofauna and microfauna of Kiel bay. He reaches the conclusion, based on the number of species which occur in each environment, that the macrofauna of sand is comparatively poor compared with mud.

The Ordovician and Silurian rocks of the Southern Uplands of Scotland have been interpreted as sediments deposited on the northern margin of the Iapetus Ocean. Trace fossils are abundant at many localities in ocean-floor turbidites and mudstones that usually lack all other evidence of life. Twelve ichnogenera are present, and they are mainly meandering locomotion and feeding trails and burrow networks: Dictyodora, Caridolites, Helminthoida, Neonereites, Nereites, Protovirgularia, Gordia, Megagrapton, Paleodictyon, Chondrites, Plano-lites and Skolithos. The trace fossils occur in at least five distinct assemblages and the composition of these was probably controlled by the frequency and nature of the turbidity currents, and possibly by the oxygen content of the mudstones. Where turbidity currents were weak, abundant Dictyodora, together with Caridolites, Neonereites, Nereites, Protovirgularia and Gordia occur in various combinations. Where currents were stronger, traces such as Gordia, Paleodictyon and Megagrapton may be exhumed and cast on turbidite soles, and the sand may contain Skolithos. The ‘deep-sea’ Nereites trace fossil facies is divisible into several assemblages, presumably environmentally controlled.

During the last eighty years the Mycetozoa have attracted the attention of numerous investigators, largely on account of the striking differences in structure which are exhibited at successive stages in the life-history. The fact that during the early stages of their development they consist of naked masses of protoplasm and closely resemble certain lowly animal forms, while later on in the sporangial condition they assume plant-like characters, has given rise to numerous discussions as to their position in the classification of living organisms.

A thick Ordovician marine flysch succession including greywackes, conglomer- ates, siltstones and shales occurs in West Nithsdale in the Northern belt of the Southern Uplands. Five new formations of Caradoc and ?Ashgill age are defined based mainly on petrographical and lithological evidence. The proposed correlation with areas up to 80 km distant to the SW, emphasises the persistent nature of the greywacke formations in the Southern Uplands when traced along strike. It is demonstrated that the main inliers of black shale in the Northern belt cannot be simple anticlines but are closely associated with large strike faults. The position of the investigated flysch succession in the accretionary prism model for the development of the Southern Uplands during the evolution of the Caledonides is indicated and its significance assessed.

The basement of the island of Nordaustlandet, northeastern Svalbard, consists of a complex of metasedimentary and metavolcanic rocks, granites and augen gneisses, unconformably overlain by the Neoproterozoic Murchisonfjorden Supergroup. Earlier U-Pb dating of the Laponiafjellet and Kontaktberget granites has shown them to be late Grenvillian, with ages of c. 960 Ma and 940 Ma, respectively. Here, we present conventional U-Pb zircon and monazite data, single zircon Pb-evaporation data and ion microprobe data from the Kapp Hansteen Group and Svartrabbane Formation volcanic and subvolcanic rocks, and from the Fonndalen and Ringåsvatnet augen gneisses of central Nordaustlandet. The combined evidence suggests late Grenvillian magmatic ages of 940–970 Ma for all these rocks, with inherited zircons ranging in age from c. 1200 Ma to 2600 Ma. The investigated rocks vary in chemical composition from andesites to rhyolites and granites, and show generally similar trace and rare earth element patterns, with trace element compositions suggesting a volcanic arc or syn-collisional tectonic setting, and major element compositions suggesting a large sedimentary input to the magmas. Contributions from older crustal material are also supported by Nd isotope data and the presence of inherited zircons.

The Grenvillian magmatic rocks thus originated in a series of magmatic events along a continental margin over a time span not longer than 30 Ma. The volcanic rocks were extruded onto folded strata of the Brennevinsfjorden Group–Helvetesflya Formation, which must have been deposited in the time interval 1200–960 Ma. Folding of the metasediments preceded the volcanism, but was synchronous with intrusion of the augen gneiss protolith, and was followed by crustal stabilisation, uplift and erosion. This newly formed Grenvillian crust then served as basement for the deposition of the Neoproterozoic Murchisonfjorden Supergroup. The present outcrop pattern of the Grenvillian rocks is largely the result of large-scale Caledonian folding and doming.

Several new gametophytes are described from the Early Devonian Rhynie chert. The new monotypic genus Remyophyton, being the gametophyte of Rhynia, is represented by a dense stand of in situ preserved gametophytes with antheridia- and archegonia-bearing axes. The gametophytes are remarkably small in comparison to those of other Rhynie chert plants. The generic diagnoses of Lyonophyton and Langiophyton are emended to include archegonia- and antheridiabearing axes. All essential stages of the reproductive cycle, i.e. sporophytes, and male and female gametophytes, can now be demonstrated for three of the six land plants from the Rhynie chert, i.e. Rhynia gwynne-vaughanii, Aglaophyton major and Horneophyton lignieri.

This and the two following papers constitute part of the report upon a detailed investigation of the normal reproductive cycle in the ewe. Although the reproductive processes of mammals have been studied intensively during the past decade, it is to the small “laboratory” mammals that most workers have devoted their attention: little is known regarding reproduction in Ungulates except in relation to the cow, which has been studied by Hammond (1927) and others.

Certain aspects of reproduction in the ewe were studied by Marshall (1903) and Assheton (1906). During the last three years many minor papers on this subject have appeared but no comprehensive account is yet available, while, as will be shown in the following pages, many of the conclusions reached by previous workers were based upon examination of insufficient material.

It is hoped that this investigation will form the basis for fuller experimental study of reproductive phenomena in the ewe, particularly as they concern breeding practice, and that it will, stimulating interest in the sex physiology of the Ungulates, assist in laying the foundations for a more thorough understanding of the physiological mechanisms underlying reproduction in this group.