# Hirnantian

> third and last stage and age of the Upper Ordovician Series / Late Ordovician epoch

**Wikidata**: [Q583151](https://www.wikidata.org/wiki/Q583151)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Hirnantian)  
**Source**: https://4ort.xyz/entity/hirnantian


## References

1. International Chronostratigraphic Chart 2013/01
2. [Source](https://stratigraphy.org/chart)
3. [Source](https://stratigraphy.org/gssps/#ordovician)
4. Freebase Data Dumps. 2013
5. [Source](https://doi.org/10.18814/epiiugs/2006/v29i3/004)
6. [Source](https://timescalefoundation.org/references/Hirnantian.pdf)