Abstract.  In sections of the Rhenish Massif, the early Namurian E1 goniatite interval (= Zone of Tumu-
lites pseudobilinguis) can be subdivided into seven goniatite zones on the basis of girtyoceratid ammonoids.
These are from bottom to top Edmooroceras pseudocoronula Zone, Edmooroceras medusa Zone, Sunder-
nites horni Zone, Tumulites angustus Zone, Tumulites pseudobilinguis 1 Zone, Tumulites pseudobilinguis 2
Zone, and Tumulites pseudobilinguis 3 Zone.  Its upper boundary with the E2 Zone is marked by the first
occurrence of Eumorphoceras grassingtonense DUNHAM & STUBBLEPIELD 1944.