The Cnoc Rhaonastil dolerite boss on Islay, NW Scotland represents a body of alkali-olivine basalt magma which differentiated at low pressure and in situ, from dolerite through teschenite to minor nepheline-syenite. The syenites occur as isolated pods and pegmatitic schlieren within the leucodolerite, and have an exotic mineralogy including Zr-aegirine, Zr-arfvedsonite, Ca-catapleiite, zirconolite and aenigmatite. Fluor-apatite occurs as an accessory phase in the dolerite, but becomes more abundant within the teschenite and syenites. Total REE contents within apatites in the dolerites are typically low (σREE = 0·57–3·21 wt.% oxide), the highest REE contents occurring in irregular, deuterically altered rims and internal patches. The REE-enriched rims also have slightly elevated SiO2 contents at 0·81–0·95 wt.%, suggesting that the substitution scheme Ca2++P5+ ⇔ REE3++Si4+ was operating. These apatites have up to 0·08 wt.% Cl and 3·7 wt.% F, with most being almost pure end-member fluor-apatite. The majority of the teschenite apatites show the least REE-enrichment (σREE = 0·27–0·45 wt.%), coupled with low Na (<0·12 wt.%) and low SiO2 (<0·39 wt.%) contents. However, within the syenites two distinct populations of apatite exist. The first, most common, variety consists of unzoned, low-REE apatites (max. 3·1 wt.% σREE, again in irregular rims and patches), whereas the second variety is often complexly zoned, and has variably enriched zones up to a maximum σREE content of 42 wt.%; this is by far the most REE-enriched natural fluor-apatite so far reported from the British Isles. The REE-enriched zones are often less than 3 μm wide, and have Na content up to 5·4 wt.% Na2O, implying that the substitution scheme Na+ + REE3+⇔2Ca2+ dominated over the more typical scheme involving Si4+ which operated in the dolerites and teschenite. Other zones are either variably enriched in Y (up 2·1 wt.% Y2O3) or Th (up to 0·85 wt.% ThO2). However, there is no correlation between Y and REE contents, suggesting that crystallographic factors were involved in apatite Y and REE partitioning. The REE-rich apatites have very low Cl content (<0·04 wt.%), but high F concentrations (<2·8 wt.%). It is believed that these strongly enriched apatites crystallised under disequilibrium conditions from isolated, variably REE-enriched domains, within the fluid-rich residual syenitic magma. These domains may have been generated by the prior crystallisation of monazite, Ca-catapleiite or zirconolite, which can be found as small inclusions within albite and interstitial analcime. The dynamic process of slumping of the denser teschenite back into the leucodolerite crystal mush is believed to have played an important role in the release of deuteric fluids and the concentration of residual magmas.

The description of the postcranial skeleton of larval, metamorphic and early juvenile specimens of the genus Discosauriscus is based on three-dimensional material and includes a description of the ontogeny of the swollen neural arches and the central elements of the vertebrae. Discosauriscus has 24 (or 23) presacral vertebrae. The morphology of the atlas–axis complex is similar to that in Seymouria sanjuanensis. The neural arches start to swell slightly in specimens of late larval stage; they are completely swollen immediately after metamorphosis. There are about 40 caudal vertebrae and one sacral vertebra. The atlantal pleurocentrum is paired in metamorphic individuals. In postmetamorphic individuals, the pleurocentra 2–5 are not completely closed dorsally; the pleurocentra 6–30 form complete discs. The first haemal arch is situated on the sixth caudal vertebra. The atlantal rib is present. There are six caudal ribs. Discosauriscus has an anocleithrum which is the first record of this dermal pectoral element within seymouriamorphs and Lower Permian tetrapods. The scapula and the coracoid are separate elements. The phalangeal formula of the manus is 2, 3, 4, 5, 3. The iliac blade has a massive, almost horizontally oriented posterior process; the anterior process is absent. The phalangeal formula of the pes is 2, 3, 4, 5, 3. Rounded ventral scales are present. The comparison and evaluation of the available postcranial elements of Discosauriscus, Utegenia, Ariekanerpeton and Seymouria support the view that Discosauriscus and Ariekanerpeton, forming the family Discosauriscidae, are immediately related genera.

Dionidid and raphiophorid trilobites are described from the middle Ordovician (Viruan Series) of Jämtland, central Sweden. The family Dionididae is represented by one genus, Dionide Barrande, 1847, and the family Raphiophoridae by five genera, Ampyx Dalman, 1827, Ampyxella Dean, 1960, Ampyxoides Whittington, 1965, Cnemidopyge Whittard, 1955 and Lonchodomas Angelin, 1854. Seven species are described and discussed. Three of these are new: Dionide jemtlandica sp. nov., Ampyxoides minor sp. nov. and Lonchodomas striolatus sp. nov.. The majority of the trilobites described are from the Andersön Shale, equivalent to the H. teretiusculus, N. gracilis and lowermost D. multidens Zones (upper Llanvirn and lower Caradoc), and the Örån Shale, equivalent to the lower D. dingani and the uppermost D. multidens Zones (middle Caradoc). Meraspid and early holaspid material of D. jemtlandica is described.

Two plants are described from fragmentary remains preserved in the Windyfield chert, situated c. 600 m from the classic Rhynie chert locality. Both are sometimes coated by a microbial film. The larger, fertile axes are placed in the new genus and species Ventarura lyonii. They possess a distinctive, sclerenchymatous middle cortex and terete xylem, and marginally dehiscent, lateral sporangia. The new taxon is similar to the Rhynie zosterophyll Trichopherophyton teuchansii, but is placed in a new genus on sporangial differences. Associated smaller axes with unicellular epidermal outgrowths lack the middle cortex of the larger axes and often have medullated protosteles. They are interpreted as subterranean rhizomes and probably belong to the new fertile taxon, but organic continuity between the two has not been demonstrated.

Microdecemplex rolfei, gen. and sp. nov., a new microarthropleuridean less than 5 mm long, is described from the Middle Devonian Panther Mountain Formation of New York State, U.S.A. The specimens consist of organically preserved cuticle, with some preserving the only cephalic structures known for arthropleurideans. A new order, Microdecemplicida, and a new family, Microdecemplicidae, are established. The probable phylogenetic position of the Microdecemplicida as one of the basal clades of Diplopoda is proposed.