Early Devonian

The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 410.62 ±1.95 million years ago to 393.47 ±0.99 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan, above the contact with the Madmon Formation.

The Lochkovian is one of three faunal stages in the Early Devonian Epoch. It lasted from 419.62 ± 1.36 million years ago to 413.02 ± 1.91 million years ago. It marked the beginning of the Devonian Period, and was followed by the Pragian Stage. It is named after the village of Lochkov in the Czech Republic, now part of the city of Prague. The GSSP is located within the Lochkow Formation at the Klonk Section in Prague.

The Pragian is one of three faunal stages in the Early Devonian Epoch. It lasted from 413.02 ± 1.91 million years ago to 410.62 ± 1.95 million years ago. It was preceded by the Lochkovian Stage and followed by the Emsian Stage. The most important Lagerstätte of the Pragian is Rhynie chert in Scotland. It is named after the city of Prague. The GSSP is located within the Prague Formation at Velká Chuchle, Prague.

first series and epoch of the Devonian system and period