A new Lagerstätte from the Late Ordovician Big Hill Formation, Upper Peninsula, Michigan

Abstract

A new exceptionally preserved marginal marine biota is reported from the Late Ordovician Big Hill Formation of Stonington Peninsula in Michigan's Upper Peninsula. The new Lagerstätte hosts a moderately diverse fauna of medusae, linguloid brachiopods, non-mineralized arthropods and orthocone nautiloids, alongside dasycladalean green algae. The biota is similar to those of Lagerstätten from the Late Ordovician of Canada, revealing an extensive distribution of a distinctive marginal marine palaeocommunity in Laurentia at this time. The Big Hill biota extends the geographical range of exceptionally preserved Late Ordovician faunas in Laurentia and indicates that further examples remain to be discovered.