Conodonts of the Ordovician Galena Formation [Iowa]

Conodonts obtained from acid residues of the Galena formation in Iowa and Minnesota are described. The long-standing question of the correlation of this unit still exists, but the new fauna recovered from the 3 members of the Galena provides additional criteria for age determination. The conodont fauna consists of 48 species which are referred to 26 genera. Three of these genera, Coelocerodontus, Goniodontus, and Rhynchognathus, are new. Belodina is proposed for species formerly assigned to Belodus. Panderodus is established for forms previously placed in Paltodus. Well-preserved conodonts are abundant in the limestone facies of the Galena, whereas they are rare and poorly preserved in the dolomite facies of that formation. Conodonts from the lower Prosser represent a continuation of the underlying Decorah fauna and are very similar to the conodonts of the Kimmswick of northern Missouri and the lower Viola of Oklahoma. A probable late Mohawkian age for these strata is indicated. Faunal elements introduced in the upper Stewartville and Dubuque suggest an early Upper Ordovician age for these beds. Detailed correlation of the members of the Galena formation with the standard Ordovician section in eastern United States cannot be accomplished at this time owing to incomplete knowledge of the faunas of the type Trenton and Cincinnatian.