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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 .
The Ordovician saw the highest sea levels of the Paleozoic, and the low relief of the continents led to many shelf deposits being formed under hundreds of metres of water. [41] The sea level rose more or less continuously throughout the Early Ordovician, leveling off somewhat during the middle of the period. [41]
This category includes biological taxa of rank more inclusive than genus that evolved during the Ordovician period of geologic time, between 485.4 and 443.8 million years ago, as well as genera and species that evolved during this time and persisted across multiple geological periods
The Darriwilian is the upper stage of the Middle Ordovician.It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 469.4 million years ago.
The Ordovician Period of the Paleozoic Era, in the Phanerozoic Eon. This category contains events which happened in the Ordovician, a division of the geologic time scale. See geologic time scale for information about its divisions and how they relate to each other.
In common practice (e.g. MLK 1952, Weller 1960) the Canadian has been viewed as the Early, or Lower Ordovician. Flower however (1957, 1964) separated the Canadian from the rest of the Ordovician and defined it as a four-part system, divided in ascending order into the Gasconadian, Demingian, Jeffersonian, and Cassinian which stands today.
This page was last edited on 19 January 2018, at 05:21 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.
Biological taxa that first appeared during the Early Ordovician epoch of geologic time, between 485.4 and 470 million years ago. See also the preceding Category:Furongian first appearances and the succeeding Category:Middle Ordovician first appearances