Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… … Wikipedia
Ordovician — Period 488.3–443.7 million years ago … Wikipedia
Ordovician Period — Interval of geologic time, 490–443 million years ago, the second oldest period of the Paleozoic Era. It follows the Cambrian and precedes the Silurian. During the Ordovician, many of the landmasses were aligned in the tropics. Life was dominated… … Universalium
Geology of the North Sea — Contents 1 Tectonic structure 2 Precambrian 3 Finnmarkian, Athollian, Caledonian Orogenies … Wikipedia
Cambrian — For other uses, see Cambrian (disambiguation). Cambrian Period 542–488.3 million years ago … Wikipedia
Carboniferous — For the album by Zu see Carboniferous (album). Carboniferous Period 359.2–299 million years ago … Wikipedia
Cretaceous — Period 145.5–65.5 million years ago … Wikipedia
Devonian — For the Celtic language, see Southwestern Brythonic language; for the residents of the English county, see Devon. Devonian Period 416–359.2 million years ago … Wikipedia
Eocene — System Series Stage Age (Ma) Neogene Miocene Aquitanian younger Paleogene Oligocene … Wikipedia
Jurassic — Period 199.6–145.5 million years ago … Wikipedia