The results of a series of experiments to study the physical processes governing the evaporation from upland vegetation in Scotland, i.e. coniferous forest, heather and grass, are described. Particular attention is given to the interception process occurring in heather, one of the dominant indigenous species in Scottish upland catchments. Attention is also given to the interception of snow precipitation which in the Scottish uplands is a significant proportion of the total precipitation. A comparison of the parameters describing the efficiency of the transport process of water vapour for coniferous forest and heather indicates that the process is more efficient than predicted by classical diffusion theory: additional transport mechanisms are considered. A simple model, based upon the results of the process studies, was applied to data from the Monachyle catchment (Balquhidder) and the model predictions compared with observations. This study, in conjunction with recent results from the Balquhidder catchment experiment, illustrates the necessity of further investigations to give a fuller understanding of the evaporation from high altitude grassland.

The Late Triassic reptile Leptopleuron lacertinum Owen, 1851 is described for the first time in full anatomical detail, based on newly produced silicone and plastic casts of the numerous specimens preserved as natural moulds. Previously, only the braincase has been described from these detailed casts. Leptopleuron is reconstructed as a 270-mm-long reptile with a long tail, although it is possible that even the largest known specimens were still sub-adults. Within Procolophonoidea, Leptopleuron is distinguished by the following non-braincase autapomorphies: two flattened, triangular spines of equal size on the quadratojugal; V-shaped groove on the jugal; the anterior tip of the jugal in contact with the posterolateral extension of the nasal; minimal contact between the jugal and the postorbital; frontals narrow anterior to the orbitotemporal openings; the vomerine dentition consisting of a tall and a short pair of fangs; broad medial ridge of pleurocentra of the dorsal vertebrae divided into three separate ridges by two deep grooves on each pleurocentrum; distinct three-fold depression pattern on the ventral side of ischium; and the first phalanx on the fifth pedal digit being long and slim. Leptopleuron shares some features with living sand lizards and might have lived a burrowing lifestyle. The dentition and body shape of Leptopleuron imply it ate a diet of fibrous plant material or hard-shelled invertebrates.

Isobaric crystallisation paths obtained from phase equilibrium experiments show that, whereas in rhyolitic compositions melt fraction trends are distinctly eutectic, dacitic and more mafic compositions have their crystallinities linearly correlated with temperatures. As a consequence, the viscosities of the latter continuously increase on cooling, whereas for the former they remain constant or even decrease during 80% of the crystallisation interval, which opens new perspectives for the fluid dynamical modelling of felsic magma chambers. Given the typical dyke widths observed for basaltic magmas, results of analogue modelling predict that injection of mafic magmas into crystallising intermediate to silicic plutons under pre-eruption conditions cannot yield homogeneous composition. Homogenisation can occur, however, if injection takes place in the early stages of magmatic evolution (i.e. at near liquidus conditions) but only in magmas of dacitic or more mafic composition. More generally, the potential for efficient mixing between silicic and mafic magmas sharing large interfaces at upper crustal levels is greater for dry basalts than for wet ones. At the other extreme, small mafic enclaves found in many granitoids behave essentially as rigid objects during a substantial part of the crystallisation interval of the host magmas, which implies that finite strain analyses carried out on such markers can give only a minimum estimate of the total amount of strain experienced by the host pluton. Mafic enclaves carried by granitic magmas behave as passive markers only at near solidus conditions, typically when the host granitic magma shows near-solid behaviour. Thus they cannot be used as fossil indicators of direction of magmatic flow.

Graphite bodies of economic importance occur in the Eastern Ghats migmatite complex of Orissa, India, which consists of sillimanite-rich gneiss (khondalite), calc-silicate granulite, basic (pyroxene) granulite and acidic gneiss palaeosomes and a variety of quartzofeldspathic neosomes and pegmatite veins. There is more graphite in migmatised khondalite and calc-silicate granulite than in their unmigmatised counterparts and it is common at pegmatite-country rock margins. Lodes of graphite are structurally controlled by fold hinge zones, necks of boudins and along the dominant foliation in rocks that show the effects of polyphase deformation. Faults, fractures and joints also act as structural controls. The richest lodes are located where there is the coincidence of several lithological and structural features.

The graphite occurs in graphite-rich schists and gneisses, as veins and as disseminated flakes along grain boundaries and in microfractures and cleavages. It is present in all rock types except pegmatites emplaced after the D4 deformational phase, and is localised in structures developed during the D1, D2, D3 and D4 phases. Most of the bodies of graphite are lenticular and show pinch and swell characters. Fourteen textural and microstructural habits have been recognised and are described with many of the features of fabric, such as intergrowths, inclusions and kinks being particularly well shown under reflected light.

Methanation of carbonate minerals is considered the most likely initial stage in the formation of the carbon with subsequent pyrolysis of the methane being the process of graphitisation. While the possibility of the carbon being either of sedimentary derivation orfrom igneous-derived CO2 cannot be ruled out, there is no convincing evidence for such sources. Remobilisation of graphite following its formation by pyrolysis of methane in structurally controlled low pressure zones is the dominant mechanism of concentration. Thefabric features point to the graphite having moved as a solid phase along open spaces inthe gangue minerals while still maintaining its crystallinity, and having been deformed in the process. The effects of remobilisation apparently have obliterated evidence relating to other methods of concentration.

To the general law, that bodies are expanded by heat, and contracted by cold, water at the point of congelation, and for some degrees of temperature above it, seems to afford a very singular and curious exception.

The circumstances of this remarkable anomaly have been for some time believed to be the following:

When heat is applied to water ice cold, or at a temperature not far distant, it causes a diminution in the bulk of the fluid. The water contracts, and continues to contract, with the augmentation of temperature, till it reaches the 40th or 41st degree. Between this point and the 42d or 43d, it suffers scarcely any perceptible change; but when heated beyond the last-mentioned degree, it begins to expand, and increases in volume with every subsequent rise of temperature.

The word “kame” is regarded by one usage as the Scottish equivalent of the Irish term “esker”; according to another usage, the terms are not synonymous, for an esker is regarded as the British representative of the Swedish “osar” and as a ridge of sand and gravel deposited along the course of a river within a glacier, while a kame is a ridge of similar materials deposited outside the glacier along its edge. The Polmont kame, as seen from the railway, strikingly resembles the Swedish osar; but it and those at Carstairs, the best known of Scottish kames, proved, on examination, not to have the cross-banding characteristic of osar, and to be marginal deposits. The typical Irish eskers are also marginal deposits (Gregory, “The Irish Eskers,” Phil. Trans., A, 210, pp. 115–51) and of the same origin as the Polmont and Carstairs kames. A few small Irish eskers have the structure of osar, while many are the remnants of denuded sheets of sand and gravel. I therefore suggested that the term esker, being Irish in origin, should be applied generally, as it is in Ireland, to hills of glacial sand and gravel.

The Early Proterozoic (1715 Ma) Harney Peak Granite (Black Hills, SD, U.S.A.) is a complex of hundreds of dykes and sills. Earlier studies of Nd, O and Pb isotope variations demonstrated that the complex was not derived from a single source, or even different sources of a single age. Instead, the granites can be divided into a group with sources probably dominated by Early Proterozoic sediments and a group with sources probably dominated by Archean sediments. New results on the Nd isotopic variations of many additional samples indicate that there is considerable overlap between Nd isotopic compositions within the complex. Values of εNd (1715 Ma) of the Harney Peak Granite suite (n = 20) range from −2·0, indicating an Early Proterozoic (2300-2200 Ma) crustal source, to −13·4, indicating a Middle to Late Archean (3200-3100 Ma) protolith. These results suggest that the Early Proterozoic source may have included rocks such as the c. 2200-1900 Ma metasedimentary rocks that occur in the southern Black Hills. The Archean sources might have included rocks such as those exposed on the periphery of the Black Hills. The range in Nd model ages negates the usefulness of the concept of the ‘average’ age of the crust in this part of the craton. Because such heterogeneity is present in the magmatic compositions of the Harney Peak Granite, it can be inferred that at least as much heterogeneity was present in the sources. In this granite system, melts were evidently derived from isolated, heterogeneous zones and did not have the opportunity to coalesce into large magma bodies. In systems where coalescence does occur, the evidence for such highly heterogeneous sources may be lost. These results emphasise that inferences drawn from a few samples of plutonic rocks in which magma mixing and homogenisation occurred can lead to erroneous conclusions about the age and nature of protoliths and, consequently, the development of continental crust.

Soils developed on basic igneous rocks, or their associated glacial drifts, are of fairly common occurrence in North-East Scotland and occupy a considerable area in Aberdeenshire. So far, only isolated studies with some specific object in view have been made of such soils, and a few descriptions with analyses have been published (Mitchell, 1936; Muir and Fraser, 1940; Whelan, 1939; Ogg, 1935). Interesting and important facts have been brought out in these investigations, but, apart from the work of Muir, no attempt has been made to study the distribution and field relations of the soils, and arable soils are mentioned only incidentally by Muir. In the present study an account is given of the classification and distribution of the various soil types occurring in the Kennethmont, Insch, Old Meldrum district of Aberdeenshire, an area which is highly farmed and which has long had a high reputation for its fertility and productivity. A soil map is given at the end of this study.

Saltopus elginensis, reported in 1910 from the yellow sandstones of the Lossiemouth Sandstone Formation (Late Triassic) of Morayshire, NE Scotland, has long been controversial. It was described first as a theropod dinosaur, but others disagreed. Reanalysis of the type, and only, specimen using casts from the natural rock moulds, as well as X-rays and CT scans, has revealed new anatomical data not available to previous researchers. Saltopus was a small, 800–1000 mm-long biped, whose tail made up more than half its length. It is an avemetatarsalian because it has elongated and tightly bunched metatarsals, the tibia is longer than the femur, the calcaneal tuber is rudimentary or absent, and metatarsal II is equal to or longer than metatarsal IV; a unique assemblage of characters diagnosing this clade. Saltopus is a dinosauromorph on the basis of the reduced fingers IV and V, the saddle-shaped dorsal margin of the iliac blade, and the articulation of sacral rib 1 close to the front of the iliac blade. Saltopus is a dinosauriform on the basis of the trochanteric shelf and lesser trochanter on the proximal end of the femur, the waisted sacral ribs, and perhaps the rod-like and straight pubis. However, it lacks all apomorphies of Dinosauria, retaining for example the primitive condition of two sacral vertebrae. Cladistic analyses place Saltopus within Dinosauromorpha and Dinosauriformes, and between the basal dinosauriform Pseudolagosuchus and the derived clade consisting of Silesauridae and Dinosauria, so making it one of a radiation of small pre-dinosaurian bipedal archosaurs in the Triassic found so far in North and South America and in Europe.

Numerous permineralised, complex medullosan pollen organs are described from Middle and Upper Pennsylvanian sediments of North America. Together with a reinvestigation of type specimens for the previously described species, these provide the basis for fully characterising internal structure and external morphology, and for recognising structural homologies among all medullosan synangia. All medullosan pollen organs, simple and complex, can be interpreted as consisting of sporangial tubes that are embedded in parenchymatous and sclerenchymatous ground tissue, and that have vascular bundles within the parenchymatous tissue. The sporangial tubes are arranged in a single series, usually a ring, with parenchymatous ground tissues and vascular bundles to the outside of the ring and sclerenchymatous ground tissue to the inside of the ring. In the larger, complex forms the ring is plicately folded and there may be a centrally-placed hollow in the distal surface. Differences in morphology, in the folding pattern of the rings, in the structure (or absence) of a distal hollow, and in architecture of the major vascular system are employed to delimit genera. Size and shape of the organ, histological features, numbers of sporangia, and presence or absence of lacunae are used to delineate species. Currently recognised genera are Dolerotheca Halle, Sullitheca Stidd et al., Stewartiotheca Eggert and Rothwell, and Bernaultia gen. nov.

This piece of work was undertaken as the result of certain observations made during class-work on irregular nutrition. This particular species of Cuscuta was being successfully grown at the time in Glasgow Botanic Gardens, and my sincerest thanks are due to Mr Banks, the Curator of the Gardens, who has very kindly allowed me to have abundant material at all times, and has also provided me with various host-plants upon which to grow the parasite. He has also allowed me to make observations on the plants growing in the Gardens, and to take photographs whenever I wished.

The life history of Petrobius brevistylis Carpenter is described from material reared in the laboratory and captured in the field (south Devonshire). A method of identifying the first eight instars is discussed and their diagnostic morphological characters described. Fecundity and time of oviposition are considered at some length. The effects of climate on various phases of the life history are considered as well as the faunas found associated with P. brevistylis. A brief description of the life history of P. maritimus (Leach) is included.

In following out the life-histories of some of the water-beetles I have been struck by the remarkable differences in habits and in structure between the members of a family, for instance, between Hydrophilus and Hydrobius, two fairly closely related genera of the Hydrophilidæ. The description of the life-history of Hydrophilus as given by Miger, Lyonnet, and others will, only to a small extent, apply to Hydrobius, although the suggestions which I am able to make with regard to certain facts in the life-history of the latter may throw light upon somewhat similar facts in the life-history of the former.

This paper describes extensive new collections of ammonites made bed-by-bed across the Oxfordian/Kimmeridgian boundary sequence in the Flodigarry sections at Staffin Bay on the Isle of Skye. The ammonites belong to the Sub-Boreal family Aulacostephanidae and the Boreal family Cardioceratidae, enabling recognition of both the current standard Sub-Boreal and Boreal ammonite zonations. In consequence, it is possible to make a close correlation of these two zonal schemes through the interval studied in Skye. The research has provided new palaeontological data at levels of precision that justify the proposal of the section at Staffin as the site of a potential Global Boundary Stratotype Section and Point (GSSP) for the Oxfordian/Kimmeridgian boundary.

The traditional Oxfordian/Kimmeridgian boundary placed at the Pseudocordata/Baylei zonal boundary of the Sub-Boreal zonal scheme corresponds precisely to the Rosenkrantzi/Bauhini zonal boundary of the Boreal zonal scheme. This level is characterised by the appearance of the first Pictonia (Pictonia flodigarriensis sp. nov.) together with first Prorasenia, replacing an older assemblage of Ringsteadia–Microbiplices (Sub-Boreal). It is also characterised by the first occurrence of small-sized Amoeboceras (Plasmatites) spp., as well as large Amoeboceras schulginae Mesezhnikov (Boreal). An alternative level that may be considered as a potential GSSP is the boundary between the Bauhini Zone and the Kitchini Zone of the Boreal zonal scheme, characterised by first occurrence of Amoeboceras (Amoebites) of the A. bayi group. This level corresponds to the Planula/Galar subzonal boundary of the Sub-Mediterranean zonal scheme, and lies close to the currently accepted Oxfordian/Kimmeridgian boundary in the Sub-Mediterranean Province.

Chondrenchelys problematica, from the Viséan (Holkerian) of Scotland, is the earliest holocephalan known from extensive cranial and postcranial material. Here, we provide a comprehensive new description of this taxon using three new specimens, in which we observe many morphological features for the first time. Much of the cranial morphology is closer to that of living chimaeroid holocephalans than was previously appreciated. For this reason, we provide original figures illustrating the chondrocranium of a hatchling Callorhinchus milii demonstrating these similarities. In Chondrenchelys, although the jaw articulation is positioned at the posterior margin of the orbit, the high-walled lamina orbitonasalis and densely-mineralised antorbital crest provide evidence for forward rotation of the jaw adductor musculature. Preserved foramina for the efferent superficial ophthalmic nerves show that the sensory organs on the rostrum were enervated in a manner similar to modern sharks, with the ophthalmic nerves not enclosed in an ethmoid canal, as in modern holocephalans. The conjunction of numerous distinctly holocephalan features with those that are otherwise general to Chondrichthyes demonstrates a decoupling of several of the structural conditions that characterise the distinctive morphological complex of the extant holocephalan skull. The anguiliform postcranium is more elongate than previously reconstructed, and it is now clear that the axial skeleton extended beyond the posterior extremity of the elongate dorsal fin. Morphological characters are reviewed with a view to further phylogenetic analyses. We recommend using the appearance of Chondrenchelys at 336.5 Ma as a hard minimum age for the last common ancestor of elasmobranchs and chimaeroids, because of its secure association with other holocephalans, and current uncertainties concerning elasmobranch stem lineage membership.

Volcanic eruptions and their deposits provide paleobiologists with an array of depositional environments in which to investigate the conditions in which exceptionally preserved flora and fauna are preserved. Studies of vegetation patterns before and after eruptions have shown that tropical vegetation makes a very rapid recovery at the vegetational level (proportion of devastated land covered). The recolonisation of the rare elements of a diversified flora, however, is slow, and so is the rebound of floristic richness, assembled over centuries from surrounding patches of vegetation and from in situ speciation.

Two major volcanic events that occurred in the past 15 years were studied in an attempt to understand the processes and complex patterns of plant deposition in volcanic landscapes. Both volcanoes gave rise to terrestrial, andesitic, explosive eruptions that gave little warning of their absolute magnitude or duration. In both eruptions, sediment-dammed lakes were formed in which a large quantity of plant material was trapped. In both instances, forests were killed and both standing and fallen trunks record the composition of the pre-eruption flora. The vegetation present in the vicinity of the volcanoes was, in the case of Mount St Helens (Washington, U.S.A.), dense coniferous forest living in a cool temperate climate and, in the case of El Chichón (Chiapas, Mexico), remnants of paratropical rainforest alternating with patches of agricultural land.

Litter layers are present under the tephra at both volcanic sites, yet the pattern of deposition and quality of the plant material differs dramatically between the two, in part because of differences in the types of eruptions and in part because of the nature of the plants available for burial. One of the most significant styles of burial, unexpected in the air-fall ash deposits, is the presence of more than one eruptive layer generated by eruptions only hours apart. These separate eruption layers have different lithological characteristics and the plant deposits buried in the different layers are different in taxonomic composition. Significantly, leaves in the upland volcanic-ash deposits are preserved thus far for 10 years, even in the tropical settings where root growth might be expected to have obliterated all signs of depositional stratigraphy. These impressions and compressions have a high likelihood of entering the fossil record and provide an excellent example of upland deposition and preservation.

The Recent Saefell tuff-ring on Heimaey, Iceland was formed by surtseyan activity in shallow seawater. The tuff-ring has a basal diameter of about 3 km, a maximum rim height of 188 m above sea-level and a crater diameter of 1300 m. Three tuff-units are recognised, separated by unconformities on and inside the crater rim due to syndepositional slumping. The crater contains a nested rim which was constructed above slumped crater tuffs. Directional data indicate strongly directed blasts to the SW at a late stage in the activity.

Throughout the volcanic activity, base-surges formed antidunes, U-shaped channels, vesiculated tuffs, small ripples and plastering structures. One antidune reflects a decrease in surge flow power during deposition and subsequent slumping due to base-surge drag and instabilities developed during growth. On the basis of field characteristics, the structures are divided into those deposited by hot, dry, fast-moving surges and those by cooler, wet, slow-moving surges. Base-surges are compared with turbidity currents and deposition of distinct structures by the head, body and tail regions is interpreted.

The changes in the vascular pattern of the pregnant rat uterus at placental sites and the intervening areas, have been studied radiologically and by injection techniques during the period of pregnancy. A description is given of the development and final pattern of the maternal placental blood channels. From the 15th day onwards wide variations are found in the vascular filling of placentæ after arterial injection. Possible mechanisms for the control of blood flow to placental sites are discussed.

The extensive series of specimens of members of the Hyolithidæ which Mrs Elizabeth Gray has collected from the Ordovician and Silurian beds of the Girvan district, and submitted to me for investigation, forms the basis of the following memoir.

Through the kindness of Dr John Horne and Professor J. W. Gregory, special facilities have been afforded me of examining the other Scotch examples in the Geological Survey Collection, Edinburgh, and the Museum of Glasgow University. My thanks are also due to Dr F. L. Kitchin for the opportunity of studying the specimens in the Jermyn Street Museum.

A survey is given of the functional morphology of extant Chelicerata with special reference to segmentation of the body, segmentation and articulation of the legs, coxal glands, mouthparts and ingestion, respiratory organs, sperm transfer, and development. This is followed by a discussion of primitive types, evolution and diversity, the transition from aquatic to terrestrial life, and the affinities of extant chelicerate groups.