Early Palaeozoic crinoids are known only patchily from the British Isles except for accumulations at starfish beds. A single, exquisitely preserved crinoid is reported from the Telychian (Llandovery, Silurian) of the Pysgotwr Grits Formation of the Llangurig area, Powys, mid-Wales. This sedimentary succession is turbiditic in origin and poorly fossiliferous. The crinoid is a diplobathrid camerate, Euptychocrinus longipinnulus sp. nov., preserved as an external mould without counterpart. It has a high, shuttlecock-like crown; a conical, unsculptured cup; low infrabasals; a pair of long, slender, feather-like arms on each ray, each bearing numerous long pinnules; and a heteromorphic column. Most previous reports of this genus have been from the Upper Ordovician – lower Silurian series of Laurentia; uncertainly, it is described from the Upper Ordovician deposits of Morocco (Gondwana). Euptychocrinus longipinnulus is the first Avalonian occurrence. The beautiful preservation of the arms, including cover plates of pinnules, contrasts with the proxistele, which is a series of ‘broken sticks’. This crinoid responded to an adverse environmental fluctuation, probably a turbidity current, by autotomizing the stem, but it was carried downslope and buried alive.

Here we record the occurrence of a new species of the Herefordshire Lagerstätte ostracod genus Pauline from the Lower Silurian (upper Telychian) of North Greenland. Pauline nivisis sp. nov. was recovered from a limestone boulder (Pentamerus Bjerge Formation) collected south of Kap Schuchert, Washington Land. It is reasonable to transpose the palaeobiology known from the Herefordshire Pauline avibella – body, limbs including swimming antennae, lateral eyes, gills and alimentary system – into the carapace of the Greenland species, which represents the oldest cylindroleberidid myodocopid and almost the oldest known myodocope, and is the first record of a Herefordshire Lagerstätte genus from outside the Welsh Borderland locality. Morphological, sedimentological and faunal evidence suggest that the Greenland species was nektobenthic. This is compatible with the notion that ostracods (specifically myodocopids) did not invade the water column until later in the Silurian, in the Wenlock and Ludlow epochs. Pauline is an Early Silurian link between ‘Baltic-British’ and North Laurentian ostracod faunas, endorsing the idea that the UK and Greenland were in close geographical proximity, near a remnant Iapetus Ocean, during late Llandovery time.

The global standard for the Llandovery Series (early Silurian) in central Wales is re-assessed in the light of detailed geological surveying, biostratigraphical sampling and a rigorous examination of published datasets. A new sedimentary and biostratigraphical architecture is presented. Key graptolite, brachiopod, acritarch and, for the first time, chitinozoan assemblages are critically assessed. Upper Hirnantian to Aeronian strata record events that followed the Late Ordovician glacial maximum and comprise a series of progradational sequences bounded by flooding surfaces, but inferred still to be glacioeustatic in origin. Significant faunal renewals associated with many of the flooding levels underpin their potential for international recognition. Compound non-sequences are a feature of proximal parts of the system where erosion associated with fault footwall uplift was an important process. Extensive slump sheets contribute to further stratal loss and displacement in distal facies. A re-assessment of the Aeronian Stage GSSP reveals shortcomings with the biostratigraphical criteria used in its selection. Telychian portions of the succession display the disrupting effects of intra-Wenlock synsedimentary sliding; hence the relevance of key published fossil assemblages and the criteria used to erect the stage GSSP are undermined. However, the Llandovery area remains one of the best studied early Silurian successions in the world. This, together with regional considerations, supports the retention of the series standard in mid Wales where the contiguous deep-water basinal succession affords internationally cited exposure of richly graptolitic facies for the whole series and, significantly, for the post-sedgwickii Biozone interval.

δ13Corg and TOC data are presented from the upper spiralis Biozone (Telychian, Llandovery, Silurian) through to the upper Sheinwoodian (Wenlock, Silurian) of the Banwy River section, Wales. In laminated hemipelagites from the Telychian, δ13Corg values rise through the upper lapworthi Biozone to a maximum in the lower insectus Biozone after which they decline slightly. The most conspicuous feature of the δ13Corg curve is the prolonged positive excursion in the Sheinwoodian, commencing in the upper murchisoni Biozone and ending in strata yielding Monograptus flexilis. This Sheinwoodian positive δ13C excursion in the Banwy River section correlates precisely with that recognized in the East Baltic. The interval with the highest δ13Corg values also records the highest TOC values, suggesting that for the Sheinwoodian at least burial of carbon may have contributed to the positive δ13C excursion. Bioturbated strata yield very low TOC values; whether the δ13Corg values from these beds reflect a primary signal or the result of biostratinomic or diagenetic modification is uncertain.