In the course of some remarks on the scheme proposed for the Forth Bridge, which remarks are published in the eleventh volume of the Transactions of the Royal Scottish Society of Arts, I was led to enunciate, among other theorems, one of a somewhat unexpected character, to the effect that any symmetric structure built on a rectangular basis, having no redundant parts, and depending on longitudinal strain alone, is necessarily unstable. This theorem was established by arguments restricted to the single matter under consideration; it is one of an extensive class, and I now propose to discuss the subject from a general abstract point of view.

We consider the reinterpretation of Bethia by Bassett et al. (2008) to be flawed in several regards. Details of the pedicle rootlets and wrinkles strongly imply a soft-tissue structure rather than calcified sheath. The ornament is unusual, but equally so under either an orthide or a plectambonitoidean model. The reinterpretation of the ‘deltial plates’ as ‘chilidial plates’ is likely correct, but argues against a plectambonitoidean affinity by implying that the pedicle emerges between the valves. Other arguments presented in favour of a plectambonitoidean affinity are also discussed; we consider them unpersuasive. Finally, we contend that Bethia is sufficiently well characterised to deserve a taxonomic name.

Coal and hydrocarbons have been exploited from the Carboniferous rocks of the Midland Valley for over 200 years. This work characterises organic matter from the Mississippian black shales of the Midland Valley from Wardie, Scotland. Biomarker analysis allowed the estimation of the degree of microbial transformation of organic matter, type of kerogen and thermal maturity during hydrocarbon generation. Parameters based on the biomarker indicators confirm a generally mixed type II/III kerogen. However, some samples contain mostly terrestrial organic matter, whilst others contain predominantly marine organic matter, which shows that the sedimentary environment varied greatly throughout the basin. The presence of gammacerane suggests water column stratification and anoxic conditions. Organic matter was much better protected from post-depositional alteration within the concretions, where higher TOC (total organic carbon) and TS (total sulphur) contents occur, than in the surrounding sediments. This can be induced by very early diagenetic formation of these concretions which protected organic matter from late diagenetic degradation.

Estimated values of vitrinite reflectance (Rc, Rcs) show that the sedimentary rocks reached the catagenesis stage. Most samples exhibit maximum organic matter maturation temperatures of around c60–90°C. However, stable isomers of phenyldibenzo[b,d]thiophene detected in some samples indicate that in some cases post-depositional hydrothermal activity affected maturation of organic matter increasing temperatures to as high as c174°C.

Ditch cuttings (69 samples) from a section of Awaizombe-1well located in the Northern Depobelt of the eastern Niger Delta Basin were used for this study. The lithology of the studied interval 1373–1812 m (439 m thick) consists of fissile grey shale and mudstone units. The scid method of sample preparation for palynormorphs’ recovery was adopted. Analysis recorded a well-preserved and diverse assemblage of palynomorphs, rich in pollen, spores and dinoflagellate cysts (dinocysts). First and last occurrences of marker and age diagnostic species were used for palynostratigraphic interpretation. Four palynostratigraphic interval range zones were established: Psilatriporites sp.–Racemonocolpites hians Zone; early Oligocene (Rupelian age), Praedapollis africanus–Doualaidites laevigatus Zone; late Eocene (Priabonian age), middle Eocene (Lutetian and Bartonian ages), Doualaidites laevigatus–Praedapollis flexibilies Zone; and early Eocene (Ypresian age), Verrucatosporites usmensis–Retitricolpites ituensis Zone. The first downhole occurrence of D. laevigatus at the 1482 m marks the late Eocene/early Oligocene boundary. Established zones are useful for inter and intra basins correlation. Lithology and age of the studied section are suggestive of the lower Agbada Formation. Palaeoenvironmental interpretations using diagnostic species revealed two environments: brackish and inner neritic to upper bathyal (0–600 m) under relatively warm-water marine condition indicated by thermophilic dinocyst taxa, such as Lingulodinium machaerophorum, Polysphaeridium zoharyi and Homotryblium spp. The lithology and these types of environments are good sites for hydrocarbon generation.

Thirty-two thrips fossils were studied from the Bembridge Marls, late Eocene of the Isle of Wight, S. England. Two extant families are recorded, Aeolothripidae with two species and Thripidae with three species. Described as new are Sinaeolothrips Shmakov gen. n. (Aeolothrips brodiei Cockerell, 1917, type species), Aeolothrips jarzembowskii Shmakov sp. nov (Aeolothripidae) and Coccothrips hoffeinsorum Shmakov, sp.nov.(Thripidae: Panchaetothripinae). The genus Thrips is tentatively recorded as fossil for the first time. Taxonomic composition of thrips is close to the Recent ones.

The morphology of sterile and fertile structures (terminal strobili) of the Upper Devonian heterosporous lycopsid Kossoviella timanica Petrosjan 1984 from northern Russia (North Timan) is re-described: the axes are dichotomously branched; sterile leaves are narrow with smooth margins; the transition from sterile axes to strobili is gradual; the strobili are narrow and cylindrical, occasionally dichotomously branched; sporophylls are long, lanceolate, with crenulated margins; megasporangia with thin, mostly destroyed, sporangium walls contain one or two tetrads of large megaspores without a gula; numerous microspore tetrads are present in the microsporangia; both mega- and microspores are cavate, with a two-layered sporoderm; the outer layer of the sporoderm of both mega- and microspores consists of a net of intertwined cylindrical elements; the inner layer of the megaspore sporoderm is a basal lamina; and the inner homogeneous layer of the microspore sporoderm is split into multilamellate zones near the arms of the proximal scar. A comparison between abortive and fertile megaspores, some of which apparently were not completely mature, allows us to hypothesise that the enlargement and lateral stretching of structural units of the sporoderm, and the spaces between them, took place during the final stages of ontogenesis of megaspores along with the additional accumulation of amorphous sporopollenin. Both layers of the megaspore sporoderm, as well as the cavity between them, developed early in the ontogenesis. Although Kossoviella timanica was certainly a unique Late Devonian plant, it bears some resemblance to the Givetian heterosporous, bisporangiate lycopsid Yuguangia ordinata in having dichotomously branching axes, sporophylls with spiny margins and strobili with proximal megasporangia and distal microsporangia. Kossoviella timanica is also similar to the Famennian bisporangiate lycopsid Bisporangiostrobus harrisii in lacking a ligula and in having dichotomously branching strobili with proximal megasporangia and distal microsporangia.

Hydrocarbon migration mechanism into a reservoir is one of the most controversial in oil and gas geology. The research aimed to study the effect of supercritical carbon dioxide (СО2) on the permeability of sedimentary rocks (carbonates, argillite, oil shale), which was assessed by the yield of chloroform extracts and gas permeability (carbonate, argillite) before and after the treatment of rocks with supercritical СО2. An increase in the permeability of dense potentially oil-source rocks has been noted, which is explained by the dissolution of carbonates to bicarbonates due to the high chemical activity of supercritical СО2 and water dissolved in it. Similarly, in geological processes, the introduction of deep supercritical fluid into sedimentary rocks can increase the permeability and, possibly, the porosity of rocks, which will facilitate the primary migration of hydrocarbons and improve the reservoir properties of the rocks. The considered mechanism of hydrocarbon migration in the flow of deep supercritical fluid makes it possible to revise the time and duration of the formation of gas–oil deposits decreasingly, as well as to explain features in the formation of various sources of hydrocarbons and observed inflow of oil into operating and exhausted wells.

Although it is very improbable that there remains to be discovered any new, and at the same time simple, fact connected with a question which has been elaborately treated by many of the greatest mathematicians of this and the preceding century, the employment of a new mathematical method may enable us to present some of their results in a more intelligible form, and with far less expenditure of analytical power than has hitherto been deemed necessary; and it may give us such an insight into the question, that we shall be able easily to discover the mutual relations among the various processes which have been already employed; so far, at least, as these differ in principle, and not merely in the peculiar co-ordinates assumed for the purpose of simplifying the equations. Such a method is that of Quaternions, which seems to be expressly fitted for the symmetrical evolution of truths which are usually obtained by the ordinary Cartesian methods only after great labour of calculation, and by modes of attack so indirect, and at first sight so purposeless, as to bewilder all but a very small class of readers. Quaternions afford so clear a view of the nature of the question they are applied to, that even the student, if he have some little knowledge of them, can often see why a transformation is made, whose object he would have been unable to discover had the problem been masked in the unnecessarily artificial difficulties of Cartesian geometry, or the outrageously repulsive formulæ of spherical trigonometry.

Brachiopod taxonomy is based on descriptions of shell morphology and key characters, but diagenesis generally modifies or erases some of them, hindering brachiopod identification. Brachiopods that are taxonomically related usually present shells with similar appearance but can differ in size (i.e., Rhynchonellata). Some aspects of morphology – for example the angular measurement of the curvature of the shell or details of shell microstructure – could aid taxonomic identification. Gigantoproductids, which lack a robust taxonomy, have the largest shells among brachiopods and are ideal for this kind of study because of their gigantic size and morphological variability. Furthermore, they have a great abundance and worldwide distribution during the mid-Carboniferous. More than 700 samples have been collected from Sierra Morena (Spain), Montagne Noire (France) and Adarouch (Morocco) identifying up to six gigantoproductid genera: Globosoproductus, Semiplanus, Kansuella?, Latiproductus, Gigantoproductus and Datangia. Microstructural features from 170 thin sections belonging to gigantoproductid ventral valves have been studied, and six crystal morphologies have been distinguished within the tertiary layer: subhorizontal, imbricated, crenulated, acicular, short and long columnar morphologies. Moreover, 23 complete shells from all genera have been selected to investigate shell size and curvature. Results from this study emphasise that shell size, curvature and crystal shape are taxa-related. Finally, a remarkable morphological change in the gigantoproductid populations from the western Palaeo-Tethys occurred during the Viséan–Serpukhovian, from thin-shelled genera with subhorizontal morphology (Viséan) to thick-shelled genera with a tertiary layer consisting of long columnar crystals (Serpukhovian). This study proves that microstructure, maximum thickness and shell spiral characterisation are robust characters when applied to gigantoproductid taxonomy, but also have great potential in other brachiopod groups.

A small fauna of vertebrates is recorded from the Insect Limestone, Bembridge Marls Member, Bouldnor Formation, late Priabonian, latest Eocene, of the Isle of Wight, UK. The taxa represented are unidentified teleost fishes, lizards including a scincoid, unidentified birds and the theridomyid rodent Isoptychus. The scincoid represents the youngest record of the group in the UK. Of particular note is the taphonomic interpretation based on the preservation of anatomical parts of land-based tetrapods that would have been most likely transported to the site of deposition by wind, namely bird feathers and pieces of shed lizard skin. These comprise the majority of the specimens and suggest that the dominant transport mechanism was wind.

The Reverend Dr Matthew Stewart, late Professor of Mathematics in the University of Edinburgh, was the son of the Reverend Mr Dugald Stewart, Minister of Rothsay in the Isle of Bute, and was born at that place in the year 1717. After having finished his course at the grammar-school, being intended by his father for the Church, he was sent to the University of Glasgow, and was entered there as a student in 1734. His academical studies were prosecuted with diligence and success; and he was so happy as to be particularly distinguished by the friendship of Dr Hutcheson and Dr Simson. With the latter, indeed, he soon became very intimately connected; for though it is said, that his predilection for the Mathematics did not instantly appear on his application to the study of that science, yet the particular direction of his talents was probably observed by his master before it was perceived by himself.

No quality is more inconsistent with the character of a stone than flexibility. A flexible stone, therefore, presents an idea which naturally strikes us with surprise. For though among mineral bodies, we find flexible substances of the stony kind, such as mica, mountain leather, and amianthus, these minerals owe their flexibility, either to their thinness, or to the fibrous structure of their parts. Therefore, when a stone of any considerable thickness is said to have flexibility, we are led to think that here is something very extraordinary; and we wish to know upon what depends that quality, nowise proper to a stone.

The most mountainous parts of Scotland are situated in its western and north-west districts. From those parts of the country, several chains of mountains branch off, and continue their courses in various directions, and to various extent. The most extended of those chains is that of the Grampians. This chain takes its rise from nearly about the centre of the above alpine district, and continues its course in a direction almost due east, or perhaps a little to the south of that point, until it disappears in the German Ocean, betwixt the towns of Aberdeen and Stonehaven.

In compliance with your request, I send you a few notes of some of the principal geological facts I observed in Faroe, which may serve as a supplement to Sir George Mackenzie's and Mr Allan's accounts of these islands, which, as far as they extend, I found perfectly correct.

The Coal in Suderoe, which was not visited by them, is situated between two thick beds of hard clay, resembling the Clunch-clay of this country; to which succeed beds of trap. In some parts, pieces of petrified wood are very abundant in the superincumbent clay, and also nodules of ironstone; and in the coal, pieces of wood resembling charcoal. The coal has the same degree of inclination as the other beds, dipping towards the south-east, at an angle of about 4° or 5°; being the same as the dip in the other islands, excepting in part of Myggenæas, where it is much greater, being near 45°.

A few years ago the late Sir C. Wyville Thomson gave me for examination some specimens of Ascidians which had been obtained during the cruises of the “Porcupine” and “Lightning,” and last summer I received from Mr John Murray the remainder of the Ascidiæ Simplices and two species of the Ascidiæ Compositæ from the same deep-sea dredging expeditions. Some additional specimens of the “Porcupine” Ascidiæ Compositæ have been placed in my hands during the last few days (January 1, 1884). The present paper contains a detailed account of the Simple Ascidians alone; the Compound forms will be worked up along with the “Challenger” Ascidiæ Compositæ, and will be described and figured in the second part of my Report upon the Tunicata of the “Challenger” Expedition. It may, however, be useful to state here that the “Porcupine” Compound Ascidians include:—

Before entering on the main subject of this paper, the composition of rainwater, I shall give a brief account of the rain that has fallen in the Lake-District during the year just past; and this I shall do chiefly by means of tables. The quantity of rain registered has been so greatly in excess of any former year, that of itself it is deserving of record, and the more so, comparing the weather which has prevailed here with the weather in the south, for the most part, happily for the harvest, as remarkable for an opposite state, an excess of dryness.

The remarkable and close parallelism exhibited by the suctorial disc of the fish Garra and of certain tadpoles belonging to frogs of the section Rana formosa of Rana was pointed out by the late Dr Annandale and myself in 1922. Evidence was then adduced to show that such structures have come into existence through a gradual accumulation of small changes, which probably originated in direct response to the increasing swiftness of the currents as the animals invaded higher and higher levels of torrential streams. The probable evolution and the development of the disc of Garra have been described already (Hora, 1921, pp. 639–643); whereas the peculiar structure of the disc in the tadpoles has hitherto been known only in its fully-formed condition. It seemed probable that, with the discovery of the earlier stages in the development of the disc, the line of evolution of the sucker would prove to be similar to that of the sucking disc of the fishes of the genus Garra (Hora, 1930, p. 241). The observations described hereafter confirm this view.