A REASSESSMENT OF THE EARLY ORDOVICIAN CELTIC BRACHIOPOD PROVINCE

In the early Ordovician, Laurentia, Baltica and Gondwana each had endemic shallow-water cratonic faunas dominated by trilobites and brachiopods as well as some more widespread faunas around the continental margins. The latter include the Toquima-Table Head faunas around Laurentia and the 'Celtic' brachiopod faunas which form the main topic of this paper. The Celtic faunas were thought to have been distributed along and offshore of only the Gondwana side of the lapetus Ocean. However, fresh analysis of the Celtic occurrences reveals a wider distribution of these brachiopods, ranging from a substantial volcanic island are (the Bronson Hill-Tetagouche-Lushs Bight Island Are) close to Laurentia to sites firmly attributable to Avalonia and possibly also Baltica. Thus, unlike most contemporary trilobite faunas, these brachiopods (which are not a homogeneous fauna) had wider Latitudinal tolerance than previously supposed, and the term 'Celtic Province' can be abandoned.