Period · Paleozoic
Ordovician
487–444 Ma
The Ordovician is a period within the Paleozoic, spanning roughly 487 to 444 million years ago. Trilobites, graptolites, brachiopods and the first large nautiloids dominate; Cincinnatian and Fezouata material are Ordovician.
| Rank | period· Paleobiology Database |
|---|---|
| Base | 487 Ma· Paleobiology Database |
| Top | 444 Ma· Paleobiology Database |
| Duration | 43.1 Myr· Paleobiology Database |
| Chart | ICS International Chronostratigraphic Chart v2023/09 (ages from Macrostrat/PBDB interval tables) |
Elsewhere
Cite this article
Stratum Study. "Ordovician" (Time interval). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/time/ordovician. Accessed 2026-09-20.
@misc{stratum-ordovician,
title = {Ordovician},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/time/ordovician}},
year = {2026},
note = {Time interval article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, pbdb. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.