The ammonoids Hudsonoceras and Baschkirites in the Morrowan series of Arkansas

Goniatites from Lower Pennsylvanian strata of northern Arkansas are described as representatives of the genera Baschkirites and Hudsonoceras, index forms of the Middle Carboniferous rocks of Eurasia. In Arkansas H. moorei, n.sp., is present in the Cane Hill Member of the Hale Formation, and B. librovitchi, n.sp., in the overlying Prairie Grove Member of the Hale Formation. Collectively, Hale goniatites indicate that the Cane Hill Member of the Hale Formation is equivalent in part to the Kinderscoutian Stage (R 1 ) of northern England and the Prairie Grove Member is equivalent to some portion of the Marsdenian Stage (R 2 ).