THE development of reliable methods of world-wide stratigraphic correlation involves the gradual replacement of empirical and traditional ‘index fossils’ by zonal index species selected on the basis ...
The Devonian (419.2-358.9 Ma) is the first geological period of the late Paleozoic, spanning about 60.3 Ma from the end of the Silurian, and its beginning is marked by the First Appearance Datum (FAD) ...