A new fossil site near Gilboa, New York, is one of only three where fossils of terrestrial arthropods of Devonian age have been found. The new Gilboan fauna is younger than the other two but richer in taxa. Fragmentary remains and nearly whole specimens assigned to Eurypterida, Arachnida (Trigonotarbida, Araneae, Amblypygi, and Acari), Chilopoda [Craterostigmatomorpha(?) and Scuterigeromorpha(?)], and tentatively to Insecta (Archaeognatha) have been found. The centipedes and possible insects may represent the earliest records known for these groups.

Differences in the preservation of Jurassic thylacocephalans and conchyliocarids have given rise to different interpretations of the form of these fossils, and thus their mode of life. When evidence from these two groups is combined with that derived from Palaeozoic concavicarids, it becomes possible to unify the several interpretations of this one group of organisms, the Thylacocephala. The group ranges from at least the Silurian to the Cretaceous.A review is given of how these differences of interpretation have arisen, and some resolution is attempted. If the thylacocephalan “anterior structure” is reinterpreted by analogy with hyperiid amphipods as a paired compound eye occupying most of the surface of the head, it explains its bilobed nature and the position of the stomach within the structure, but it raises the difficulty of a post-cephalic origin for the carapace. The simpler solution is preferred of regarding this structure as discrete paired eyes with a smooth cornea and subjacent crystal cones.The raptorial appendages are post-oral and post-adductor in insertion. They are therefore tentatively identified as the maxillae and maxilliped, but verification of the mandible's position is needed to test this. The postero-ventral battery of “body somites” is reinterpreted as paired protopods of abdominal limbs. A respiratory current is deduced to have entered a branchiostegal chamber ventrally, and left it posterodorsally. It is speculated that the looped linear pattern of intra-cuticular spheres in Paraostenia are photophores. The large eyes with small interommatidial angles were probably used to discern low contrast prey or carrion against a dim background. By analogy with hyperiid amphipods, it is suggested that at least some thylacocephalans were mesopelagic predators. They may have attained neutral buoyancy from their food substrate of shark and coleoids.

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Restoration of the morphology of Angustidontus seriatus Cooper, 1936 based on complete specimens from the Famennian of Nevada and Poland, supports its affinity to the coeval alleged decapod Palaeopalaemon and suggests eocarid (possibly also peracarid) affinities. Predatory adaptation of the thoracopods and the relatively short pereion make this crustacean only superficially resemble the archaeostomatopod hoplocarids, because the large grasping appendages of Angustidontus represent the first, rather than second, maxillipeds and acted in the opposite direction: downward. Another similar adaptation of the antennae in the Viséan Palaemysis suggests a widespread adaptation to predation among early eumalacostracans. The large sample collected from the Woodruff Formation of Nevada permits biometric characterisation of the grasping maxillipeds of Angustidontus, showing that their highly variable morphology should not be used to define species. All previously described species are therefore here synonymised with A. seriatus. Differences in gnathobases of mandibles found in articulated specimens in Nevada, and associated with isolated maxillipeds and articulated specimens possibly representing another unnamed species in Poland, suggest that such mandibles may eventually prove to be taxonomically more significant.

SynopsisThe limb of Arthropleura is shown to be uniramous and not biramous as suggested by Waterlot and accepted by all subsequent authorities except Størmer. The functional significance of some of the limb features is apparent from comparison with living myriapods. The rosette, K- and B-plates are suggested to be sub-coxal sclerites and not limb segments, appendages or organs as previously maintained. New reconstructions of the limb and of the whole animal are presented. Arthropleura is here regarded as a member of a distinct class of Myriapoda, the Arthropleurida, which differs from all other myriapods in the large number of segments in the limb and in the presence of the rosette plate. A juvenile specimen of Arthropleura has lycopod fragments preserved as gut contents, proving that this creature was herbivorous and not carnivorous as suggested by Waterlot. This herbivorous habit is one of several features indicating parallel evolution of the Arthropleurida and the living polydesmid millipedes.

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An unusual, laminated, spherulitic limestone with cherty layers forms part of a volcanogenic sequence in the Midland Valley of Scotland, 27 km west of Edinburgh. It preserves a cross section of the early Carboniferous terrestrial community. Microcrystalline silica laminae containing inclusions of calcite or dolomite may be primary, and support a hot-spring origin for the deposit. Oxygen isotope analyses of the silica and carbonate are consistent with the precipitation of silica from hot, possibly boiling, hydrothermal solution. Such hot spring waters were presumably heated by hypabyssal intrusives associated with the West Lothian volcanic center, only 5 km to the northwest. Silica was probably precipitated by acidification when such waters entered a very local, fresh-water lake. At the same time, calcium carbonate was precipitated from surface water, due to an increase in temperature and reduction in acidity. Such precipitates covered wide areas of the lake floor and the fossils lying on it. Algal or bacteriogenic precipitation may have been responsible for the formation of accretionary growths around nuclei of wood, other fossils, and rock clasts.The preserved terrestrial biota includes almost-complete individuals of a reptile and of four amphibian groups: temnospondyls, anthracosaurs, loxommatids, and aistopods. These are the oldest known, fully land-going tetrapods. Truly aquatic forms are absent. Invertebrates include: large eurypterids, which may have been partially terrestrial; the oldest known proven terrestrial scorpion (Gigantoscorpio); the earliest harvestman "spider"; and millipedes. Several land-plant assemblages are found in the sequence. Permineralized plants show exceptional anatomical preservation when enclosed withinDownloaded from 14 W.D.I. Rolfe and Others accretionary nodules. Fusainized (charred) gymnosperm wood and pleridosperm leaves indicate the presence of wildfires.Fully articulated amphibian skeletons occur within the laminated limestones, whereas only disarticulated skeletons have been collected from the lapilli tuffs. Such taphonomic evidence supports an epiclastic origin for the volcaniclastic rocks, deduced from study of clasts and bedform analysis. Fragments mass-flowed or were rain-washed from the flanks of a small basaltic volcano onto or into an area of sinter deposition.

The Foulden Site of Special Scientific Interest is one of the few Cementstone Group localities that yields significant fauna and flora. Excavations in 1980 and 1981 removed a 1·3 m2 slab of the Fish Bed for laboratory study of the vertical and spatial distribution of the biota. Layer by layer analysis revealed an almost mutually exclusive relationship between the vertical distribution of the palaeoniscoid fishes and malacostracan crustaceans, as well as a horizon crowded with juvenile acanthodians. Elongate elements of this biota showed slight preferred orientations at that prolific horizon. Some 27 m of strata including the Fish Bed, Plant Bed and Shell Bed are recorded in detail, and their biota noted. Interim results of work on the main groups collected are summarised in associated papers in this part of Transactions. Brief reports are given here on the euryhaline marine bivalve mollusc Modiolus latus (Portlock), a rare durophagous bradyodont shark tooth and an Eogyrinus-like amphibian scute.