- Geology. noting or pertaining to a period of the Paleozoic Era, 405 to 345 million years ago, characterized by the dominance of fishes and the advent of amphibians and ammonites.
- of or relating to Devonshire, England.
- Geology. the Devonian Period or System.
- of, denoting, or formed in the fourth period of the Palaeozoic era, between the Silurian and Carboniferous periods, lasting 60-70 million years during which amphibians first appeared
- of or relating to Devon
- the Devonian the Devonian period or rock system
- The fourth period of the Paleozoic Era, from about 408 to 360 million years ago. During this time there were three major landmasses: most of modern day North America and Europe were located along the equator; a portion of Siberia was located to the north; and a continent consisting of South America, Australia, Africa, India, and Antarctica was located in the Southern Hemisphere. In the early Devonian small plants dominated the landscape, but by the end of the Devonian ferns and seed plants had appeared, as had the first forests. The first tetrapods (terrestrial vertebrates) and terrestrial arthropods appeared, as did many new types of fish. See Chart at geologic time.