تعريف devonian period في الإنجليزية الإنجليزية القاموس.
Interval of geologic time from 417 to 354 million years ago; it was the fourth period of the Paleozoic Era. During the Devonian, a giant continent was situated in the Southern Hemisphere (see Gondwana), and other landmasses were located in the equatorial regions. Siberia was separated from Europe by a broad ocean, and North America and Europe were joined. Many types of primitive marine and freshwater fish appeared and proliferated, and the period is sometimes referred to as the Age of Fishes. Ferns and primitive gymnosperms diversified and created the first forests