The triplesiid genus Streptis, hitherto unknown from pre-Llandovery rocks in Norway, is described from the Upper Ordovician unit 5a of Holmen in Asker, Oslo Fjord. The species, S. undifera (Schmidt) (syn. S. incompta Ulrich & Cooper), was previously recorded only from the Porkuni Stage (= 5b) of Estonia. The relationships of this species to other early Streptis are discussed in the light of morphological trends, and possible routes of migration of the genus suggested.
The occurence of Streptis (Brachiopoda) in the Ordovician of the Inner Oslo Fjord