A Conodont Fauna from the Joins Formation (Ordovician), Oklahoma

Abstract

The Joins Formation has yielded more than 5,800 conodonts, which represent 56 species and 26 genera. Eleven species are described for the first time. The fauna has affiniries with faunas previously described from Lower Ordovician and Middle Ordovician rocks of the midconrinent and portions of the formation contain elements characteristic of BalroScandian faunas of Arenigian age. The Joins fauna is herein suggested to be part preChazyan and pan post-Canadian in age. Work on the brachiopods and graprol ites from previous Joins stud ies has indicated a transition between Chazyan and Canadian faunas. The present work corroborates these past studies and offers new evidence for the suggested age determination in the form of diagnostic conodonts.