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The Ordovician–Silurian extinction events may have been caused by an ice age that occurred at the end of the Ordovician Period, due to the expansion of the first terrestrial plants, [54] as the end of the Late Ordovician was one of the coldest times in the last 600 million years of Earth's history.
This is a timeline of Irish history, comprising important legal and territorial changes and political events in Ireland. To read about the background to these events, see History of Ireland . See also the list of Lords and Kings of Ireland , alongside Irish heads of state , and the list of years in Ireland .
South of the Brigantes, the geographer Ptolemy reported three tribes whose territories stretched from the Irish Sea to the North Sea. The Ordovices occupied the westward lands and had two noteworthy cities, Branogenium which was located 195 Roman miles from London, most likely at Leintwardine, and Mediolanum which was located 200 Roman miles from London.
The period between the start of the Iron Age and the historic period (AD 431) saw the gradual infiltration of small groups of Celtic-speaking people into Ireland, [18] [19] with items of the continental Celtic La Tene style being found in at least the northern part of the island by about 300 BC.
The Great Ordovician Biodiversification Event (GOBE) was an evolutionary radiation of animal life throughout [1] the Ordovician period, 40 million years after the Cambrian explosion, [2] whereby the distinctive Cambrian fauna fizzled out to be replaced with a Paleozoic fauna rich in suspension feeder and pelagic animals.
The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician .
View history; Tools. Tools. move to sidebar hide. ... Ordovician Ireland: geologic formations from the Ordovician Period of the Paleozoic Era in Ireland
The Sandbian is the first stage of the Upper Ordovician.It follows the Darriwilian and is succeeded by the Katian.Its lower boundary is defined as the first appearance datum of the graptolite species Nemagraptus gracilis around 458.2 million years ago.