Cephalopods from the late Eocene Hoko River Formation, northwestern Washington

Abstract

Rare specimens of the nautiloidsNautilusandAturiaand extremely rare specimens of a sepiamorph sepiid are described from the late Eocene Hoko River Formation, northern Olympic Peninsula, Washington. The well-preserved partial phragmocones are from channel-fill clastics deposited on the inner and middle slopes of a submarine-fan system.TheNautilusspecimen is allied toN. cookanumWhitfield from middle Eocene strata, New Jersey, and is probably conspecific withNautilussp. (Miller) from late Eocene strata, northwestern Oregon, both of which were previously assigned toEutrephoceras.This is the first record ofNautilusin the northeastern Pacific.TheAturiaspecimen is tentatively identified asA.cf.A. alabamensis(Morton), a species previously only known from late Eocene strata in the Atlantic-Gulf Coastal area and northeastern Mexico.Aturia alabamensismay be the same as numerous Eocene North American aturiid species.The two sepiamorph sepiid specimens resembleBelosepiaVoltz but are probably generically distinct. They are only the second record of sepiids in the Eocene of the northeastern Pacific.