The ichnofauna of the Skiddaw Group (early Ordovician) of the Lake District, England

Deep-marine strata of the Skiddaw Group, deposited in high southerly palaeolatitudes on the northern margin of Eastern Avalonia in the early Ordovician, contain a diverse ichnofauna dominated by examples of fodinichnia. This includes Alcyonidiopsis pharmaceus, several ichnospecies of Chondrites, Dictyodora zimmermani, Glockerichnus radiatus, Gordia marina, Ixalichnus enodius, two or possibly three ichnospecies of Phycodes, Planolites montanus, Volkichnium volki, an ‘arthropod-produced? repichnion’, ‘paired pits’, ?Gordia aff. marina, ‘thinly-walled, looping, burrows’ and burrows of Planolites/Palaeophycus affinity. Stellascolites radiatus Etheridge, 1876 is reassigned to the ichnogenus Glockerichnus Pickerill, 1982 as Glockerichnus radiatus (Etheridge, 1876). Several of the ichnotaxa are present in other ichnofaunal assemblages of early Ordovician age which were also emplaced at high southerly palaeolatitudes. The relatively high diversity of this ichnofaunal assemblage supports suggestions that models of the rate at which the deep-marine environment was colonized during the early Phanerozoic are in need of revision.