The Lower Cambrian Sirius Passet fauna from Peary Land, North Greenland, is a rich repository of soft-bodied and poorly-sclerotised fossils. A new arthropod from the fauna, Kleptothule rasmusseni, is described. The animal is broadly trilobite-like, possessing a trilobed exoskeleton which is divided into distinct cephalic, thoracic and caudal regions. However, it is unusual in that it possesses a large number of segments, and demonstrates pronounced cephalic segmentation, and a very narrow cephalon and thorax. There is some evidence that the exoskeleton was lightly mineralised.

Kleptothule is compared to some of the olenellimd trilobites, especially those taxa that possess a many-segmented ‘opisthothorax’. Its morphology raises some issues discussed by Lauterbach (1983) in his assignment of some olenellids to the stem-group of the chelicerates. However, it is not considered herein that such a model can be supported. A complete analysis of basal trilobites and the stem-group leading to them must await a fuller description of key taxa from China and Greenland.

The upper Cambrian trilobite Olenus wahlenbergi Westergård, 1922 occurs abun- dantly in stinkstone concretions in the Alum Shales at Andrarum, in Skåne, southern Sweden (Olenus/Homagnostus obesus Zone). All growth stages from anaprotaspis onwards are represented, though the early stages are comparatively uncommon and complete specimens are rare. Fine details of structure are preserved, suitable for scanning electron microscopic study.

The protaspis has five axial rings, which in the adult become divided transversely and reduced to three, and the preglabellar field expands markedly in the holaspis. The librigena broadens during development and the eye, with its widely separated lenses is retained on the librigena throughout meraspid development. The visual surface dehisces during ecdysis from the early holaspid onwards, due to emplacement of the ocular suture. The hypostome apparently changes from a conterminant to a natant condition in the early holaspis, which is consistent with the growth of the preglabellar field at this stage. The transitory pygidium has a slightly serrated margin throughout development, but becomes entire when all thoracic segments have been liberated.

Cuticular sculpture changes dramatically throughout ontogeny. Large (Type A) tubercles appear on the fixigena in early meraspides; these become prominent and coalesce by the end of meraspid development. They are abruptly replaced by smaller (Type B) tubercles in the early holaspid, which link to form a rough network in mature specimens. Comparable Type A tubercles in early meraspid librigenae give rise to a strong polygonal caecal sculpture in holaspids, while a radial sculpture on the broadening anterior border develops independently. The significance of these cuticular changes remains obscure. A median occipital organ is described for the first time in the Olenidae.

The early Tertiary Mull-Morvern lava succession, NW Scotland, represents the thickest continuous section (1000 m from sea level to the top of Ben More) of Tertiary lavas exposed in the UK. This succession has been sampled and geochemically analysed, on a flow-by-flow basis, throughout the lava succession. Field observations during the course of this sampling suggest that the early lava flows (the Staffa Magma sub-Type) ponded in palaeovalleys along with interlava sediments. In the main part of the Mull lava succession (the Mull Plateau Group) the lava flows are on average ∼ 5 m thick. Most previous Hebridean workers have assumed that the red horizons commonly found between these later lava flows, represent weathered flow tops. However, this study has shown that in some places these red ‘boles’ appear to be a combination of both volcanic ash and weathered basalt.

Chemically distinctive units of flows have been found throughout the succession. The two most abundant magma sub-types of the Mull Plateau Group, primitive (>9wt% MgO) basalts with Ba/Nb» 15 and more evolved (<9wt% MgO) basalts-hawaiites with Ba/Nb<15, form packets of flow units which can be up to 200 m thick. These chemically distinctive flow units have been correlated across the lava succession. However, the correlation of individual lava flows has proved difficult. The Mull Plateau Group lavas generally become more evolved and less contaminated with continental crust towards the top of the succession, culminating in the trachytes of the Pale Group on Ben More. Basaltic lavas above the Pale Group have markedly different trace element ratios, and seem to represent shallower, more extensive asthenospheric melting than the Mull Plateau Group.

Manned submersible dives were conducted in the submarine canyon channel system of Porcupine Seabight, NE Atlantic Ocean. Visual observations were made, and sediment samples collected and analysed to elucidate the nature of the sedimentary regime. In the upper part of the canyon (480-940 m water depth) sediments consisted of a mixture of terrigenous quartz rich silts and sands, skeletal carbonate of benthonic and planktonic origin and minor clay minerals and authigenic dolomite. There were localised Lophelia pertusa coral thickets on both the flanks and floor of the canyon. Sedimentary structures and physical measurements revealed there to be active transport of sediments in the canyon down to a depth of at least 940 m, effected by (?tidal) reversing currents and bioturbation. In these parts of the canyon, deposits around glacial dropstones and coral thickets indicate that there has been a maximum of 0-1 m of net sediment accumulation since the last glacial period. At 3000 m water depth, in the channel system, the sediments were fine calcareous ooze with a drape (up to 0-3 m thick) of flocculant phytoplankton detritus. At these depths, there was no evidence for present-day sediment resuspension by currents.