Ordovician period


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Related to Ordovician period: Permian period, Devonian period, Silurian period

Ordovician period

a period of the PALAEOZOIC ERA which occurred between 515 and 445 million years ago. Algae, particularly calcareous, reef-building forms, were common as were graptolites, corals and brachiopods. The first armoured fish evolved in the Ordovician.
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References in periodicals archive ?
During the Ordovician period, 450 million years ago, Wales was on the border of two ancient tectonic plates, and was to be found 30 south of the Equator.
A team of scientists led by the Universities of Exeter and Oxford set out to identify the effects that the first land plants had on the climate during the Ordovician Period, which ended 444 million years ago.
The limestone layers in which you found your specimen were formed in shallow water during the Late Ordovician Period, about 450 million years ago.
The organisms, from the Ordovician period which began about 495 million years ago, were found in Llanfawr quarry near Llandrindod Wells.
His own archive is one of the most complete of the time, helping him to explain how the Scottish Highlands were founded - and to define the Ordovician period of geological time.
The rocks at the mountain's summit are marine limestones that still contain fragments of tiny marine organisms, notably conodonts, from the Ordovician Period (505-440 mya).
The oldest widely accepted fossils of land organisms hail from the Ordovician period, 475 million years ago.
The earliest horseshoe crab fossils date to the late Ordovician period, roughly 450 million years ago.
In 2006, a group of Andalusian geologists found the oldest fossils in the Cordillera Betica, dating from the late Ordovician period between 446 and 444 million years ago, in the Malguide Complex in Ardales (Malaga).
Fossil fish scales discovered in Colorado reveal that sharks have been haunting the seas since the middle of the Ordovician period 455 million years ago, a time far more ancient than paleontologists previously thought.

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