An unusual mid-Cambrian faunule from St. John's Island, Fortune Bay, Newfoundland

Abstract

Three trilobites, Hypagnostus aff. clipeus, Cotalagnostus sp. nov., and Pagetides johannis sp. nov., not previously recorded in Newfoundland, are associated with Onymagnostus cf. hybridus, H. mammillatus, Peronopsis cf. fallax minor, Paradoxides (P.) davidis davidis, P. (P.) cf. abenacus, Brunswickia (B.) cf. jaculator, B. (Jincella) sp., Agraulos sp., and some hyolithids, stenothecid molluscs and orthid, acrotretid and lingulate brachiopods in a thin limestone within dark grey, slaty mudstones of the Young's Cove Formation on St. John's Island, Fortune Bay. A stratigraphical position within the Cambrian punctuosus Zone in the upper part of the Drumian Stage is indicated. The presence of the oculate eodiscid Pagetides in late mid-Cambrian rocks, within the Avalon Tectonostratigraphical Zone, is highlighted, because the genus was previously only known associated with the much earlier Cambrian olenellid zones of Laurentia. Paradoxides (P.) cf. abenacus and the species of Brunswickia (B.) close to peregrina, respectively, provide a link with the New Brunswick mid-Cambrian and paradoxissimus successions in England and Scandinavia, whereas the specimens of Hypagnostus aff. clipeus indicate a more global significance in common with forms in the punctuosus sequences of Siberia and Australia. The St. John's Island sequence includes lithofacies and fossils typical of the Manuels River Formation preserved elsewhere in southeastern Newfoundland. This is the first recognition of such a sequence in the Young's Cove Formation of Fortune Bay on the western margin of the Avalon Tectonostratigraphical Zone.