The experiments described in this paper were suggested to me many years ago, when employed in studying the Geological System of the late Dr Hutton, by the following plausible objection, to which it seems liable.

Granite, porphyry, and basaltes, are supposed by Dr Hutton to have flowed in a state of perfect fusion into their present position; but their internal structure, being universally rough and stony, appears to contradict this hypothesis; for the result of the fusion of earthy substances, hitherto observed in our experiments, either is glass, or possesses, in some degree, the vitreous character.

A Fertile shoot of Protopitys scotica sp. nov. from the Calciferous Sandstone Series of Dunbartonshire provides the first available information about the reproductive structures of Protopitys which most authors have hitherto regarded as probably a Pteridosperm. The evidence, however, suggests that it is a plant with pteridophytic reproduction. The range in size of the spores suggests too that heterospory with two sizes of spores, megaspores and microspores, was in course of evolution. It is proposed that a new group, the Protopityales, be established to include Protopitys.

Pyrite textures are described and illustrated and stable S-isotope data are presented from the Alton (Gastrioceras listen) marine horizon of the Westphalian Lower Coal Measures, from sections near Penistone in central northern England, with the object of relating the paragenetic sequence of pyrite formation to the conditions of sediment deposition and diagenesis. The earliest diagenetic pyrite is dispersed as framboidal and related textures. It is followed in the marine shale, coal and ganister by more localised but more intense pyrite deposition and replacement in a variety of textures. Most of this is precompactional in age, but some, together with pyrite in veinlets and cleat, is postcompactional. Marcasite is rare and mainly late. δ34S ratios range between −35·31‰ and +20·39‰. There is a definite trend from lighter values (−1·15 ± 6·47‰) in the marine part of the sequence to much heavier values (+12·73 ± 7·66‰) in the sediment below the coal. This allows the relationship of the earliest pyrite deposition in the coal-peat and ganister to the chemistry of their own depositional fresh water to be seen but then relates the main pyrite deposition to the influx of the marine-water sulphate of the Alton horizon, and shows the penetration of this influence downward into the coal-peat and its seat-bed.

The primary focus of this review is on P-T conditions, mineralogical indicators of melt or fluid composition and textural evolution; lesser treatment is given to pegmatite sources or to pegmatite-wallrock interactions. Investigations of stable and radiogenic isotopes have revealed that the source materials for pegmatites are likely to be more heterogeneous or varied than previously thought, especially for peraluminous pegmatites, but that overall pegmatites bear a clear intrusive relationship with their hosts, as opposed to an origin in situ. The P-T conditions of crystallisation of some lithium-rich pegmatites have been constrained by lithium aluminosilicate stability relations in combination with stable isotope or fluid inclusion methods. Experimental studies have elucidated the effects of components such as Li, B, P and F, which are common in some classes of pegmatites, to liquidus relations in the hydrous haplogranite system. Experimentation has also provided corroboration of an old concept of pegmatite crystallisation—that pegmatites owe their distinctive textures and mineral/chemical zonation to relatively rapid crystallisation of melt from the margins inwards at conditions far from the equilibrium (i.e. from supercooled liquids). The origin of aplites, whether alone, layered, or paired with pegmatites, remains an active area of research. Studies of fluid inclusions, crystal-vapour equilibria and wallrock alteration have helped to define the timing and compositions of vapour phases in pegmatites and to aid in the economic evaluation of deposits.

Dolomites form in a range of environments by processes able to drive large volumes of magnesium-rich waters through existing carbonate sediments or rocks. These fluids need not be of unusual composition but there are kinetic barriers to crystallisation which is influenced by factors such as the Mg/Ca ratio, salinity, temperature, the /Ca2+ ratio and time. Dolomite is able to form at near-surface temperatures and pressures within a few thousand years.

Textures in dolomitic rocks are controlled by their conditions of formation. A large proportion are replacive but few of these are mimetic, preserving primary structures. Crystals vary from euhedral to anhedral with boundaries ranging from planar to consertal. Solution chemistry and temperatures influence the density and distribution of nuclei together with growth rates and crystal morphology. There is still doubt whether irregular crystal faces are products of high or low temperatures or saturation. Dolomite cements are more important than has previously been realised in massively dolomitised rocks. Differential dissolution of aragonite, calcite, or evaporite minerals leaves space for these cements to occupy. Dolomitisation may also be allied to compaction, generating stylolitic rocks which are progressively enriched in dolomite. Dolomite may be replaced by calcite or it may be dissolved and the resulting pores filled with a calcite cement.

There is no general correlation between any set of petrographic features and particular geological models for dolomitisation. Similar physicochemical conditions are reproduced in a range of environments and the most effective guides to origin are in the geometry and regional petrographic variation of dolomite bodies.

Silurian sediments up to 2500 m thick are exposed in the Pentland Hills, SW of Edinburgh. These sediments, the North Esk Group, are here sub-divided into five well-defined formations: the Reservoir Formation, Deerhope Formation, Cock Rig Formation, Wether Law Linn Formation and Henshaw Formation. The Wether Law Linn Formation is further sub-divided into three members. Based on limited palaeontological evidence, the sediments appear to be late Llandovery (crenulata Biozone) to Wenlock in age. The Silurian sediments represent a regressive sequence, passing from offshore submarine-fan turbidite facies, through shallow marine sediments, with an abundant flora and fauna, possibly a barrier complex, to terrestrial red beds of Old Red Sandstone facies. Changing faunal associations in the shallow marine sediments reflect the availability of different substrates. The regression occurred on the southern margin of the Midland Valley graben.

The following investigation was commenced, in the first place, to provide information for class use, for, in spite of the fact that thousands of specimens of Squalus acanthias and S. sucklii are used every year in North America, there appears to be no satisfactory account of the blood vascular system of either species available. As the work proceeded, various problems arose which necessitated references to the conditions in other species and the preparation of more detailed dissections than are usually made in class work. It is well known that there is considerable confusion in the nomenclature employed by different authors for even some of the main vessels, and it was soon evident that this is not merely individual preference but, in part, due to a more fundamental lack of agreement as to the precise morphological significance of the vessels themselves. More recent embryological investigations by other workers have, we consider, given a key to the solution of the most important of these problems and have shown that, in so far as the blood-vessels are concerned, the Elasmobranchs lie closer to the other gnathostomatous vertebrates than is generally recognised, and indeed furnish a primitive and generalised type. The time seemed ripe, therefore, to provide a connected account of the vascular system in an Elasmobranch, viewing it in the light of the researches just referred to, and of what is known of the distribution of the various vessels in the sub-class in general. It was hoped that this would provide an epitome that would serve as a basis for future work in the sub-class, and also for comparison with the conditions in higher vertebrates.

The axial skeleton and fin supports of the Middle Devonian lungfish Dipterus are described from a range of specimens from the Orcadian Basin of Scotland. The axial skeleton of the trunk region consists of intercentra, relatively short ribs, and neural arches bearing two rows of supraneural spines; posteriorly, the intercentra are replaced by haemal arches. The notochord seems to have been essentially unconstricted. There may have been two pairs of cranial ribs. In general terms the vertebral column resembles that of Neoceratodus but is more fully ossified. The only known paired fin support of Dipterus is an archipterygial structure resembling those of Neoceratodus, with at least seven mesomeres and jointed pre- and postaxial radials. The pectoral fin is rotated as in modern lungfishes. The median fin supports all consist of basal plates supporting radials. In the posterior dorsal fin support the posterior radials form a branched structure. The heterocercal tail is supported by segmental radials. A new body reconstruction is presented.

The characters possessed by Dipterus offer support for a lungfish–porolepiform sistergroup relationship. All known lungfishes fit into a single cumulative series of postcranial morphologies. The evidence for a paedomorphic trend in lungfish phylogeny is interesting but inconclusive.

It does not always happen that the memory of inquirers into nature, who have the merit or the fortune to strike first into a right path, is cherished as it deserves. This remark applies forcibly to the eminent person, whether regarded as a physiologist or as a physician, of whose life aud labours a brief memoir is now laid before the Society. The name of Robert Whytt was familiar to his contemporaries both at home and abroad. Increase of distance should hardly yet have dimmed its lustre. Yet, in proportion as the views which he initiated have expanded more and more in growing to maturity, the less and less is heard of their author. Biography—which never did Whytt great justice—begins already to put him aside. A few particulars of his life, with a catalogue of his works, have hitherto been common in books of that description, principally in those of Germany and France. In some newer French biographies his name has dropped out. But of a late Edinburgh Biographical Dictionary, extending to not a few volumes, while restricted to the lives of eminent Scotsmen, it will hardly obtain credit that an early luminary of the rising University, conspicuous among the European leaders of medical science during a busy period of the eighteenth century, should, amidst a cloud of mediocrity, be there sought for in vain.

Comb-layered quartz is a type of unidirectional solidification texture found at the roofs of shallow silicic intrusions that are often associated spatially with Mo and W mineralisation. The texture consists of multiple layers of euhedral, prismatic quartz crystals (Type I) that have grown on subplanar aplite substrates. The layers are separated by porphyritic aplite containing equant phenocrysts of quartz (Type II), which resemble quartz typical of volcanic rocks and porphyry intrusions. At Logtung, Type I quartz within comb layers is zoned with respect to a number of trace elements, including Al and K. Concentrations of these elements as well as Mn, Ti, Ge, Rb and H are anomalous and much higher than found in Type II quartz from Logtung or in igneous quartz reported elsewhere. The two populations appear to have formed under different conditions. The Type II quartz phenocrysts almost certainly grew from a high-silica melt between 600 and 800°C (as β-quartz); in contrast, the morphology of Type I quartz is consistent with precipitation from a hydrothermal solution, possibly as α-quartz grown below 600°C. The bulk compositions of comb-layered rocks, as well as the aplite interlayers, are consistent with the hypothesis that these textures did not precipitate solely from a crystallising silicate melt. Instead, Type I quartz may have grown from pockets of exsolved magmatic fluid located between the magma and its crystallised border. The Type II quartz represents pre-existing phenocrysts in the underlying magma; this magma was quenched to aplite during fracturing/degassing events. Renewed and repeated formation and disruption of the pockets of exsolved aqueous fluid accounts for the rhythmic banding of the rocks.

The main object of tho present paper is the consideration of the structure of the Central and S.W. Highlands as shown up by the metamorphic condition of the beds. This metamorphic condition has boon studied over the length and breadth of the country, mapped and deduced from very many outcrops in all districts. Sometimes it was possible to superpose the the details respecting the metamorphism upon the 1-inch maps of the Geological Survey, but in many other cases the areas were mapped upon the 6-inch scale. Naturally this work has taken a long time, for it has necessitated the collection of many thousands of specimens, and nearly 3000 rocks have been sliced and examined, since it is not always possible to define the limits of a metamorphic zone with precision by field work alone, and many rock types were encountered that rendered a more careful study advisable than was possible from the mere examination of a hand specimen.

In Patagonia a Triassic-Early Jurassic Cordilleran interior magmatic belt preceded the widespread eruption of Middle Jurassic syn-extensional rhyolites. Two plutons (La Calandria and La Leona) represent the easternmost plutonic rocks of this belt, > 750 km east of the present oceanic trench. They define a high-K calc-alkaline monzonite series in contrast with the main Andinotype arc magmatism of the Pacific margin: they are enriched in large ion lithophile elements (K, Rb, Ba, Sr and Th), LREE and P2O5 and depleted in HREE and Y, with low FeO*/MgO ratio. The range of observed compositions (56-76% SiO2) resulted from high-level fractionation of plagioclase, hornbleńde, biotite, K-feldspar and accessories (sphene, apatite and zircon).

Initial 87Sr/86Sr ratios, average εNdt and mean depleted-mantle Nd model ages of the two plutons are 0·70487, -0·5 and 1050 Ma for La Calandria and 0·70509, -1·4 and 1125 Ma for La Leona, respectively. They are thus isotopically more primitive than the Middle Jurassic rhyolites, previously attributed to partial melting of Mesoproterozoic mafic lower crust. The preferred model for the origin of the monzonites is remelting of an amphibole- + garnet-bearing, plagioclase-poor, high-K mafic source (?underplating). This occurred in a distal sector of a dying oblique subduction regime, immediately preceding the extensional silicic volcanism.

The last Scottish Ice Sheet (SIS) expanded from a pre-existing ice cap after ∼35 ka. Highland ice dominated, with subsequent build-up of a Southern Uplands ice mass. The Outer Hebrides, Skye, Mull, the Cairngorms and Shetland supported persistent independent ice centres. Expansion was accompanied by ice-divide migration and switching flow directions. Ice nourished in Scotland reached the Atlantic Shelf break in some sectors but only mid-shelf in others, was confluent with the Fennoscandian Ice Sheet (FIS) in the North Sea Basin, extended into northern England, and fed the Irish Sea Ice Stream and a lobe that reached East Anglia. The timing of maximum extent was diachronous, from ∼30–27 ka on the Atlantic Shelf to ∼22–21 ka in Yorkshire. The SIS buried all mountains, but experienced periods of thickening alternating with drawdown driven by ice streams such as the Minch, the Hebrides and the Moray Firth Ice Streams. Submarine moraine banks indicate oscillating retreat and progressive decoupling of Highland ice from Orkney–Shetland ice. The pattern and timing of separation of the SIS and FIS in the North Sea Basin remain uncertain. Available evidence suggests that by ∼17 ka, much of the Sea of the Hebrides, the Outer Hebrides, Caithness and the coasts of E Scotland were deglaciated. By ∼16 ka, the Solway lowlands, Orkney and Shetland were deglaciated, the SIS and Irish Ice Sheet had separated, the ice margin lay along the western seaboard, nunataks had emerged in Wester Ross, the ice margin lay N of the Cairngorms and the sea had invaded the Tay and Forth estuaries. By ∼15 ka, most of the Southern Uplands, the Firth of Clyde, the Midland Valley and the upper Spey valley were deglaciated, and in NW Scotland ice was retreating from fjords and valleys. By the onset of rapid warming at ∼14.7 ka, much of the remnant SIS was confined within the limits of Younger Dryas glaciation. The SIS, therefore, lost most of its mass during the Dimlington Stade. It is uncertain whether fragments of the SIS persisted on high ground throughout the Lateglacial Interstade.

In geochemical diagrams, granitoids define ‘trends’ that reflect increasing differentiation or melting degree. The position of an individual sample in such a trend, whilst linked to the temperature of equilibration, is difficult to interpret. On the other hand, the positions of the trends within the geochemical space (and not the position of a sample within a trend) carry important genetic information, as they reflect the nature of the source (degree of enrichment) and the depth of melting. This paper discusses the interpretation of geochemical trends, to extract information relating to the sources of granitoid magmas and the depth of melting.

%Applying this approach to mid-Archaean granitoids from both the Barberton granite–greenstone terrane (South Africa) and the Pilbara Craton (Australia) reveals two features. The first is the diversity of the group generally referred to as ‘TTGs’ (tonalites, trondhjemites and granodiorites). These appear to be composed of at least three distinct sub-series, one resulting from deep melting of relatively depleted sources, the second from shallower melting of depleted sources, and the third from shallow melting of enriched sources. The second feature is the contrast between the (spatial as well as temporal) distributions and associations of the granites in both cratons.

The discovery of marine Pliocene diatoms in warm-based glacial deposits (now termed the Sirius Group) high in the Transantarctic Mountains in the 1980s began a three-decade-long controversy over the stability of the East Antarctic Ice Sheet. Their presence implied that this ice sheet had collapsed as recently as three million years ago to allow their deposition in shallow interior seas, followed by transport and deposition from an expanded over-riding ice sheet. Though the glacial deposits included clasts with older diatoms, no evidence of clasts with Pliocene diatoms was published, but the hypothesis gained wide acceptance. Increasing knowledge of ice sheet behaviour and the antiquity and stability of the Transantarctic Mountains, along with new techniques for dating age and denudation rates for landscapes, has led to a more likely alternative hypothesis – that the high-level Sirius Group deposits pre-date Transantarctic Mountains uplift and their Pliocene diatoms are atmospheric contaminants. Surveys have shown that marine diatoms from the Antarctic margin and the Southern Ocean are indeed reaching the surface of the ice sheet and blowing through the mountains, with permafrost processes providing opportunities for contamination. Modelling and geological evidence is now consistent with a stable East Antarctic Ice Sheet in the interior for the last 14 Ma, with some retreat around the margins and periodic collapse of the West Antarctic ice sheet in Pliocene times.

Archival and recent boreholes over an area of c. 3 km2 have revealed complex magma-host interaction at the termination of an olivine–dolerite sill in Fife. The sill interior has zones rich in plastically deformed, vesiculated heterogeneous sediment surrounded by amygdaloidal basalt. Sediments at the contacts have been reconstituted and enclose blebs of chilled vesicular basalt. Intrusion into low rank coal seams has produced multicomponent tuffisite. A vertically nested and laterally fingered sill front is envisaged as having propagated down dip under a thin cover (<500 m) of wet Namurian sediments. Non-explosive bulk interaction of fluidised sediment and devolatilising magma occurred at intrusive contacts. Steam explosivity was more vigorous where lobes of magma repeatedly intruded moist lignite, to produce compositionally banded tuffisite rich in basalt clasts and coal fragments. The hydrovolcanic explosions did not give rise to surface eruptions because the low volumes of porewater and the high permeability and low tensile strength of the lignite prevented a build-up of high pressure steam.

The mechanisms by which Cordilleran plutons are emplaced vary widely. However, the present authors have examined a series of plutons ranging from 2–35 km emplacement depth that have many common features, which suggest that downward transport of host rock is the most important mechanism during magma ascent and pluton emplacement. Many of these Cordilleran plutons preserve gently dipping, unfaulted roofs attached to steep walls bordered by narrow ductile aureoles. Flat lying roof strata commonly roll over into steeply dipping rim monoclines and anticlines that young towards and follow the pluton margin. Field observations suggest that such rim monoclines and anticlines formed due to gravitationally driven roof collapse and channel flow along margins. In the examples in this paper, pluton walls are often comprised of narrow steeply dipping ductile aureoles in which the intensity of strain increases downward. Aureole ductile strains are insufficient to account for the volume of magma emplaced, and are typically <40% of pluton volume. However, when aureole strain is combined with minimum estimates of stoping and host rock rotation during rim monoclines formation, sufficient space can be created. The examples suggest that gravitationally driven downward host rock transport by stoping and rigid rotations along roofs and walls and by focused channel flow by ductile strain along walls are common processes during the rise of Cordilleran plutons, and is one process that contributes to crustal thickening and the growth of crustal roots.

Lower Old Red Sandstone drainage of the Caledonian mountain chain in the northern British Isles converged in the region of the present North Channel between Scotland and Ireland. Calculations of possible catchment area of this drainage network suggest a major river system c. 530 km in length comparable to parts of the present day drainage network of the Himalayas. Evidence from the Lower Old Red Sandstone sedimentary assemblages in Northern Ireland and Scotland indicates that tributaries flowed NE and SW parallel to the Caledonian mountain front. These tributaries joined a trunk stream which flowed southward from present western Scotland through the southern part of the present Inner Hebrides region, and on through the region of the present North Channel and terminated in the contemporaneous Devonian sea. The coastline of this sea stretched E-W across southern Britain.

The essential drainage system established in Lower Old Red Sandstone times became re- established in Upper Old Red Sandstone times, but with a channel network with palaeoflow to the NE in Scotland. This probably joined a southerly flowing trunk stream in the North Sea region, possibly parallel with the western Scotland-Irish Sea drainage.

This research was begun in 1929, and a preliminary account of some of the results of the investigation was published in the Journal of Anatomy, January 1932. It was initiated by the discovery, during experiments on intravitam staining in the guinea-pig, that dye-bearing cells collected in large numbers in the endometrium of the uterus and that their incidence there was cyclic. The first results were obtained in animals injected immediately after parturition and killed at intervals thereafter. In a short series of virgin animals, the series being established by determining the date of heat by the vaginal smear method (Stockard and Papanicolaou, 1917, 1919), practically identical results were obtained.

Nebria brevicollis (F.) and Philonthus decorus (Grav.) are two of the commonest predaceous insects of the woodland floor, and the head structure, mouthparts and feeding methods of each have been compared and contrasted. In N. brevicollis, the mandibles are well developed for the capture and shearing of the prey, whilst the laciniæ of the maxillæ form rakes which pull the food towards the cibarium across the smooth labium. Food is bolted in large pieces and stored in the crop before passing through the filtering and grinding gizzard. A fundamental difference between the two beetles is seen in the movements and structure of the maxillæ, and a mechanism whereby stipital abduction and protraction is effected in N. brevicollis has been proposed. In P. decorus, the mandibles are also developed for prey capture but hold the prey between large brushes while it is being crushed. The maxillæ form thick brushes which also hold the prey, and the labium-hypopharynx is densely covered with setæ which prevent the entry of solid food into the mouth. Thus, in contrast to N. brevicollis, the labrum has a median food groove which directs the food upwards and away from the mouth, and returns it to the mandibles to be re-chewed. Here, partial external digestion occurs and fluid food is sucked in by the powerful cibarial pump, and passed to the filtering proventriculus. In order to show how the two feeding methods described fit into the general pattern, the feeding methods of various predaceous Coleoptera have been reviewed in relation to different types of gut structure.