Origin of Ordovician
Related formspost-Or·do·vi·cian, adjective
Examples from the Web for ordovician
They were more than likely the undisputed masters of the Ordovician seas.Geology|William J. Miller
The Silurian strata are mostly found in the same localities as those which furnish exposures of the rocks of Ordovician age.
It consists essentially of an island of Ordovician (Lower Silurian) limestone, surrounded by the later systems.Early Western Travels 1748-1846, Volume XIV|Edwin James
That it was not, however, entirely a mud groveller is indicated by its widespread distribution in middle Ordovician times.The Appendages, Anatomy, and Relationships of Trilobites|Percy Edward Raymond
The characters of the Ordovician trilobites have already been noticed.