The Devonian is a geologic period and system of the Paleozoic Era, spanning 60 million years from the end of the Silurian Period, about 419.2 million years ago (Mya), to the beginning of the Carboniferous Period, about 358.9 Mya. It is named after Devon, England, where rocks from this period were first studied.The Devonian period experienced the first significant adaptive radiation of life on dry land. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. Various terrestrial arthropods also became well-established. Fish reached substantial diversity during this time, le