Type
Zone
Age range
422.7–421.2 Ma
Pridoli
Ludlow
Ludfordian
Oulodus elegans detortus
Ozarkodina eosteinhornensis
Ozarkodina crispa
422.7422.6422.5422.4422.3422.2422.1422.0421.9421.8421.7421.6421.5421.4421.3421.2