At the end of 1926 a paper by Dr Maclaren entitled “Development of Cavia: Implantation” was published in the Transactions of the Royal Society of Edinburgh (2). In this he dealt with the process of implantation of the blastocyst, and incidentally gave a tentative interpretation of the nature of the layers of which it was formed. The paper was to have been followed by a further contribution dealing especially with the earlier stages in the history of the blastocyst. This was held up for various reasons, and was not ready for publication until 1930, when there appeared appaperd on the subject by Professor Hill and Dr Sansom (6). This forestalled to a considerable extent Dr Maclaren's demonstration of the facts of observation, but there remained to him more than a dozen examples of free blasto-cysts at younger stages of development than the earliest figured in their paper, and indeed of any other worker on the development of Cavia. He then thought that it might be more interesting and instructive if the fixed and sectioned material were controlled by observations on the living blastocyst. A technique for this was developed, and apparatus designed by which living blastocysts could be observed and photographed. Eminently successful in the case of mammals with large blastocysts and tardy implantation, the results obtained in Cavia were disappointing owing to the excessive minuteness of the blastocyst, and to its being very early involved in one of the crypt-like recesses in the mucosa.

The greater part of this Monograph is devoted to detailed descriptions of 1426 samples of deposits from the floor of the Atlantic Ocean stored in the Challenger Office, Edinburgh, which had been collected during thirty-five cruising expeditions between 1857 and 1911. The remaining part discusses the results of the work.

We undertake a re-interpretation of eighteen sheets of the 1: 100,000 Geological Survey map of Italy. Developing the tectonic discoveries of G. Steinmann and S. Lencewicz we group the pre-Middle Miocene rocks of the district in four structural units beginning with the lowest as follows: (1) The rocks seen through the Carrara Window; (2) Spezia Nappe; (3) Liguria Nappe; (4) Genoa Nappe. Our account mainly concerns the Liguria Nappe. In it we find too much layering to admit of G. I. Migliorini's invocation of successive piecemeal landslips. We also cannot agree with certain important features of R. Staub's synthesis of Mediterranean tectonics.

That there must be a medium forming a continuous material communication throughout space to the remotest visible body is a fundamental assumption in the undulatory Theory of Light. Whether or not this medium is (as appears to me most probable) a continuation of our own atmosphere, its existence is a fact that cannot be questioned, when the overwhelming evidence in favour of the undulatory theory is considered; and the investigation of its properties in every possible way becomes an object of the greatest interest. A first question would naturally occur, What is the absolute density of the luminiferous ether in any part of space? I am not aware of any attempt having hitherto been made to answer this question, and the present state of science does not in fact afford sufficient data. It has, however, occurred to me that we may assign an inferior limit to the density of the luminiferous medium in interplanetary space by considering the mechanical value of sunlight as deduced in preceding communications to the Royal Society from Pouillet's data on solar radiation, and Joule's mechanical equivalent of the thermal unit.

Some time ago, at the request of Professor Ewart, I undertook an examination of the skull and visceral skeleton of the Greenland shark, Læmargus microcephalus. This I readily consented to do, not only because no attempt had yet been made to describe these structures in this shark, but because they claim careful consideration in view of the recent work by Professor Ewart on the cranial nerves of Elasmobranchs.

In this paper I shall endeavour, without entering into too much detail, to point out some of the more salient features of the skull and visceral skeleton of Læmargus, and to compare them with those of other Elasmobranchs where that seems necessary.

I have made preparations of the above-named structures from the heads of several specimens of Læmargus. The sharks from which the heads were taken were of various sizes, the smallest being about six feet in length, and the largest twelve. As might have been expected, the skeletal parts of these heads are very similar to each other, but I have noticed among the few specimens I have examined points of difference, which make me wish I had a larger number of preparations at my disposal, to enable me to decide the more usual conditions.

The greater part of Kintyre is composed of metamorphic rocks. For the study of these rocks it is convenient to divide the peninsula into three separate areas as follows:—

A. Northern Kintyre.

B. The south-western corner of the peninsula.

C. A triangular area stretching from Campbeltown Loch southward (fig. 1).

A. With the exception of a few isolated patches of Palæozoic sandstones, conglomerates, and lavas, and igneous rocks of several ages, Northern Kintyre is composed of sedimentary schists and grits, metamorphic limestones, and schistose igneous rocks which, as a rule, are associated with the limestones.

The Coal Measures of the South Wales Coal Field fall into three well-marked divisions:—

I. The Upper Pennant or Upper Penllergare Series.

II. The Lower Pennant Series.

III. The White Ash Series.

In 1885 I paid a visit to this Coal Field, with the object of studying its Fossil Flora, hoping by this means to ascertain the relative position of the Welsh Coal Measures to those of the other Coal Fields of Britain.

The highly specialised features of the Compositæ leave little room for doubt that the family is an advanced one, and it is not without significance that the vast majority of its species should be herbaceous plants; shrubby species are infrequent, while trees are of the rarest occurrence. The markedly herbaceous habit is further emphasised if attention is confined to the large and widespread genus Senecio, comprising over 2000 species, for, although they include plants of very diverse habit, few attain to tree dimensions, or possess a well-developed, perennial, woody trunk. Herbs or shrubs account for 99 per cent, of the species, the former greatly predominating. The remainder comprises a small group of about 20 species, which have assumed the arborescent habit.

The Galway Granite Complex is unique among the British and Irish Caledonian granitoid terranes, as it records punctuated phases of magmatism from ∼425–380 Ma throughout the latest phase of the Caledonian Orogeny. Remapping of the Omey Pluton, the oldest member of this suite, has constrained the spatial distribution and contact relationships of the pluton's three main facies relative to the nature of the host rock structure. The external contacts of the pluton are mostly concordant to the limbs and hinge of the Connemara Antiform. New AMS data show that a subtle concentric outward dipping foliation is present, and this is interpreted to reflect pluton inflation during continued magma ingress. Combined field, petrographic and AMS data show that two sets of shear zones (NNW–SSE and ENE–WSW) cross-cut the concentric foliation, and that these structures were active during the construction of the pluton. We show that regional sinistral transpression at ∼420 Ma would have caused dilation along the intersection of these two fault sets, and suggest that this facilitated centralised magma ascent. Lateral emplacement was controlled by the symmetry of the Connemara Antiform to ultimately produce a discordant phacolith. We propose that regional sinistral transpression at ∼420 Ma influenced the siting of smaller intrusions over NNW–SSE faults, and that the later onset of regional transtension caused larger volumes of magma to intrude along the E–W Skird Rocks Fault at ∼400 Ma.

The aquatic diplocaulid nectridean Keraterpeton galvani is the commonest taxon represented in the Jarrow Coal assemblage from Kilkenny, Ireland. The Jarrow locality has yielded the earliest known Carboniferous coal-swamp fauna in the fossil record and is, therefore, of importance in understanding the history and diversity of the diplocaulid clade. The morphology of Keraterpeton is described in detail with emphasis on newly observed anatomical features. A reconstruction of the palate includes the presence of interpterygoid vacuities and new morphological details of the pterygoid, parasphenoid and basicranial region. The hyoid apparatus comprising an ossified basibranchial element has not been reported previously in nectrideans. The structure of the scapulocoracoid and primitive nature of the humerus is described and the presence of a five-digit manus confirmed. Previously unrecognised accessory dermal ossifications are present in the pectoral girdle. Keraterpeton longtoni from the Bolsovian in Staffordshire, England, is also described and newly figured. The primitive condition in diplocaulids is defined on the basis of the earliest occurrence at Jarrow and discussed in relation to functional morphology and mode of life. The evolution of the diplocaulid clade is assessed in relation to the revised diagnoses that define the primitive condition in Keraterpeton.

The rocks which form the Maltese islands have been at various times referred to very different parts of the Cainozoic group. At first they were all assigned to the Eocene, but a further knowledge of their fossils led to the transference of the whole series to the Miocene, in which system they have been included by most English writers. Herr Th. Fuchs, However, who first attempted any precise determination of the horizons of the subdivisions, correlated the Upper Limestone with the Leithakalk and the Blue Clay with the Schlier, and included the two lowest beds in the Oligocene. Dr Murray, however, in the course of his recent Memoir, has explained the striking palæontological differences between the faunas of the different deposits as due to altered conditions of formation rather than to lapse of time, and seems to follow earlier authors in including the whole series in the Miocene.

The Echinoidea of these deposits were originally described by Dr Wright in 1855,§ with additions and corrections in 1864; but since that time much work has been done on the allied faunas.

A number of approaches to interpreting geochemical data for categorising and correlating metabentonites are presented. Bulk rock geochemistry, combined with data from cognate minerals, provides the most robust means of characterising an altered ash bed. While it is not possible at present to identify one single parameter which can uniquely fingerprint an altered ash bed, it is possible to come close to an unique fingerprint, or ‘Golden Spike’, by utilising an array of geochemical parameters comprising bulk rock element ratios, Rare Earth Elements, Sr and Nd isotopic ratios in apatite, composition of sandine phenocrysts, and the chemical composition of melt inclusions.

Abundant as are the localities in which garnet is found in Scotland, there are but few which yield specimens such as can be analysed.

This is on account of an intermixture of quartz—for the most part in a granular form—the granules being promiscuously scattered throughout the mass of the crystals. In three localities the intermixture is not promiscuous, but has been governed by some intermittent crystalline action. These localities are Glen Skiag in Ross, where, around a central nucleus of leucitoidal crystals of garnet, translucent quartz is arranged in layers which alternate with those of the garnet, conformably to the figure of its crystal.

The two other localities are the first and third granitic veins to the east of Portsoy; in both of which garnet of a pale brown colour is laced with quartz, which is arranged in a graphic manner, as in the felspar from an adjacent vein. At no other locality do I know of such an occurrence. The appearance of a section of a rhombic dodecahedron is somewhat like the figure.

In the year 1810 there appeared in Robert Brown's Prodromus Floræ Novæ Hollandiæ et Insulæ Van Diemen, p. 160, a brief description of a rare Australian Fern to which the generic name Platyzoma was given. The habit of stem and leaf, and in general the form and position of the sporangia, led Brown to the conclusion that Platyzoma was of Gleicheniaceous affinity. It was noted that the plant was heterophyllic; for not only did it possess pinnate leaves suggestive of those of certain Gleichenioid forms, but also small, compressed, and filiform leaves devoid of pinnæ. To the form of the larger and pinnate leaves Brown paid particular attention, noting chiefly that the leaves of Platyzoma were unbranched, whereas a branched condition was typical of the leaves of Gleichenias. This unbranched condition of the leaf seemed to Brown a sufficiently distinctive feature to justify the foundation of a new Gleicheniaceous genus —the monotypic genus Platyzoma; and he named the single species Platyzoma microphyllum.

The Glasgow area has a combination of highly variable superficial deposits and a legacy of heavy industry, quarrying and mining. These factors create complex foundation and hydrological conditions, influencing the movement of contaminants through the subsurface and giving rise locally to unstable ground conditions. Digital geological three-dimensional models developed by the British Geological Survey are helping to resolve the complex geology underlying Glasgow, providing a key tool for planning and environmental management. The models, covering an area of 3200km2 to a depth of 1.2km, include glacial and post-glacial deposits and the underlying, faulted Carboniferous igneous and sedimentary rocks. Control data, including 95,000 boreholes, digital mine plans and published geological maps, were used in model development. Digital outputs from the models include maps of depth to key horizons, such as rockhead or depth to mine workings. The models have formed the basis for the development of site-scale high-resolution geological models and provide input data for a wide range of other applications from groundwater modelling to stochastic lithological modelling.

In order to elucidate how mineralogy and composition of crustal sources influences production of leucogranite magmas, we modelled the potential fertility of a sequence of metapelites and metagraywackes from the Black Hills, South Dakota, U.S.A., using a least-squares mixing approach. Rocks analogous to the Black Hills schists were the sources of the Harney Peak leucogranite. Both muscovite and biotite fluid-absent melting reactions (MM and BM, respectively) were investigated. Using the Harney Peak Granite composition as the melt analogue and mineral compositions from the schists for mixing calculations, it is shown that MM of metapelites would lead to highly variable residue mineralogy in the investigated samples. The average residue includes 36 wt.% biotite, 32 wt.% quartz, 12 wt.% plagioclase, 8 wt.% K-feldspar, 9 wt.% sillimanite and 2 wt.% garnet. Melt production ranges from 5% to 23% with an average of 14%. It is limited by the amount of H2O that must be in the melt at the conditions of melting, relative to the amount that is in muscovite in the source rocks. Plagioclase-rich metagraywackes contain little to no muscovite, thus MM cannot occur in them.

Although BM is continuous over a wide temperature range, for the purposes of modelling melting at 975°C and 10kbar was chosen. The temperature is near the terminal stability of biotite, thus the calculations give near-maximum melt production. At this temperature, the mineralogy of the model residues from both metapelites and metagraywackes is dominated by garnet. The potential melt production in the metapelites ranges from 0% to 58% with an average of 32%. It is limited by the availability of plagioclase in the source rocks. Potential melt production in the metagraywackes ranges from 9% to 37% with an average of 23%. At the chosen conditions of melting, melt production is limited by the available K in biotite, although at lower temperatures, the available H2O limits melt production. The total potential melt production (MM + BM) in the metapelites is higher because they have on average a low normative An/Ab ratio (0·14) that approaches the ratio in the leucogranites (0·04). The paragonite component in muscovite significantly contributes to the low ratio in the metapelites. The higher ration (0·27) in the metagraywackes is denned by the feldspar composition.

Using the calculated melt fractions and residue mineralogies, we modelled the concentrations of Rb, Sr and Ba in the melts, as these elements are important indicators of melt-generating processes. The results indicate that both Sr and Ba are likely to be heterogeneous in extracted melt batches and will be depleted in partial melts relative to their pelitic sources, irrespective of whether the melting is fluid-absent or fluid-present.

Before submitting the results of my examination of the silicates, it is incumbent upon me to give an outline of the processes adopted for their analysis, seeing that the amount of confidence which is to be placed in the results must rest very immediately thereupon.

1. Determination of the Water. — In all silicates which were found, after thorough drying, to give out moisture when heated in the closed tube, the amount of loss upon ignition was calculated as water. About 2 grammes, crushed in the diamond mortar, were first merely heated throughout in the air-chamber of a water-bath, the contact temperature of which was 212° Fahr., the temperature of the air-space being never below 199°. The weight after this heating was taken; and, except in the case of a mineral functioning in any peculiar way, the loss in weight was estimated as hygroscopic moisture. The mineral was now continuously heated in the bath until the weight was found to be constant. It was then exposed for the space of one hour to a full red heat, in the flame of a Bunsen burner, after which it was re-weighed. Finally, it was exposed for ten minutes to a heat approaching whiteness, in a three-jet Griffin blast-furnace, again re-weighed, and again heated in this furnace, until the weight was constant.

In 1843 I presented a paper to the Royal Society of Edinburgh, giving an account of experiments made on the boiling point of water in the Alps, under various barometric pressures. My object was twofold: first, to describe an apparatus which I considered more practically available than those previously in use; and, secondly, to give a simple, and, as I believed, new formula for computing heights from such observations.

With reference to the second point, I became aware, some time after the publication of my paper, that Sir John Leslie had proposed to compute heights by the thermometer, assuming the change of the boiling point to be exactly in proportion to the height ascended. While cheerfully conceding to Sir John Leslie priority on this point, I submit that he did not bring forward experiments to justify its practical adoption.

Before giving a description of the specimen which forms the subject of this communication, it seems desirable that a brief summary of the literature dealing with the internal structure of Sigillaria, and some general remarks on the classification of the genus, should be given.

More for the purpose of convenience than on scientific grounds, the genus Sigillaria is usually divided into four groups. These groups were originally supposed by their founders to be of generic value, but experience has shown that the characters on which they were founded are more or less common to all four divisions, and in some cases the distinctive divisional characters even occur on the same specimen.

The Lower Ordovician (Oeland Series) type species of Lamanskya, L. splendens Moberg & Segerberg 1906, was described originally as an articulate brachiopod, but it is here redescribed and referred to the lingulid Family Elkaniidae. L. splendens ranges from the late Tremadoc to the early Arenig in Baltoscandia (Norway, Sweden, Estonia, and the St Petersburg district of Russia). Aulonotreta kuraganica Andreeva 1972 from the Lower Ordovician of the Ural Mountains is also redescribed and referred to Lamanskya. The genus Dictyobolus Williams & Curry 1985, from the Lower Ordovician of Ireland, is a junior synomym of Lamanskya. All species of the genus are strongly biconvex, and have a well-developed ornamentation of elongate lenticular pits. The problematic Genus Volborthia von Moller 1870 is also considered tentatively to belong within the Elkaniidae.