In geologic time, the Devonian Period, the fourth period of the Paleozoic Era, covers the time roughly 410 million years ago (mya) until 360 mya.

The Devonian Period spans three epochs. The Early Devonian Epoch is the most ancient, followed in sequence by the Middle Devonian Epoch, and the Late Devonian Epoch.

The Early Devonian Epoch is divided chronologically (from the most ancient to the most recent) into the Gedinnian, Siegenian, and Emsian stages. The Middle Devonian Epoch is divided chronologically (from the most ancient to the most recent) into the Eifelian and Givetian stages. The Late Devonian Epoch is divided chronologically (from the most ancient to the most recent) into the Frasnian and Famennian stages.

In terms of paleogeography (the study of the evolution of the continents from supercontinents and the establishment of geologic features), the Devonian Period featured continued cleavage of supercontinent landmass and fusion of...