noting or pertaining to a geologic period of the Paleozoic Era, from 500 million to 425 million years ago, notable for the advent of fish.
the Ordovician Period or System.
The Ordovician /ɔrdəˈvɪʃən/ is a geologic period and system, the second of six
of the Paleozoic Era, and covers the time between 485.4 and 443.8 million ...
The Ordovician Period lasted almost 45 million years, beginning 488.3 million
years ago and ending 443.7 million years ago.* During this period, the area north
Learn about the Ordovician period and get information, facts, and more about
prehistoric periods from National Geographic.
The organisms are bizarre, thrilling things from the dawn of "higher life" that disappear from the record in later rocks. Except that now a similar body of younger rocks, of Ordovician
age, has been found in Morocco bearing many Burgess-type organisms, still swimming
a... More »
During the Ordovician Life expanded in diversity tremendously. There were
extensive reef complexes in the tropics. The early Ordovician was thought to be
Sep 29, 2015 ... The Ordovician Period was also characterized by the intense diversification (an
increase in the number of species) of marine animal life in what ...
Sep 10, 2015 ... Global extinction event occurring during the Hirnantian Age (445.2 million to
443.8 million years ago) of the Ordovician Period and the ...
The Ordovician Period is the second period of the Paleozoic Era. This important
period saw the origin and rapid evolution of many new types of invertebrate ...
World Paleogeography and Paleoclimate: From the Early to Middle Ordovician,
the earth experienced a milder climate. Siberia and Baltica were separate, and ...