Protosalvinia dawson and associated conodonts of the Upper trachytera Zone, famennian, Upper devonian, in the eastern United States

Protosalvinia first occur in association with conodonts of the Upper trachytera Zone and below the Three Lick Bed in the Ohio Shale and the Ellicott Shale of the central and northern Appalachian Basin, as well as in the Clegg Creek Member of the New Albany Shale of the Illinois Basin. In the Chattanooga Shale of the southern Appalachian Basin, Protosalvinia are found no lower than the Upper marginifera Zone or associated with obviously reworked conodonts in the Middle expansa Zone. Regionally Protosalvinia are associated with a disconformity and may be found with conodonts of the Lower expansa Zone.