The Middle Ordovician of the Oslo Region, Norway. 17. Conodonts from the lower Middle Ordovician of Ringerike.

55 species of conodonts are reported from two localities in the Ringerike district. The age of the fauna, determined by correlation with Swedish conodont faunas, is uppermost Llandeilian or basal Caradocian. Chemical composition of the conodonts has been investigated by use of spectrographic techniques. Problems concerning the genus Loxognathus are discussed. An attempt is made to relate groups of conodont "species" to original organisms using statistical methods and the results are compared with groupings of conodont "species" described from the Pratt Ferry Formation of Alabama (Sweet & Bergström, 1962).