The
Fortunian stage marks the beginning of the
Phanerozoic eon, the
Paleozoic era, and the
Cambrian period. It is the first of the two stages of the
Terreneuvian series. Its base is defined as the first appearance of the trace fossil
Treptichnus pedum million years ago. The top of the Fortunian which is the base of the
Stage 2 of the Cambrian has not been formally defined yet, but will correspond to the appearance of an
Archeocyatha species or "Small shelly fossils" approximately million years ago.