The oldest period to be represented in the rocks of Fforest Fawr Geopark; it lasted from 485 to 444 million years ago.
The Ordovician Period
This period extended over 45 million years. It is divided into three series/epochs, which are further subdivided into various stages/ages.
- Late/upper Ordovician epoch (458Ma – 445Ma)
- Hirnantian stage (445Ma – 444Ma)
- Katian stage (453Ma – 445Ma)
- Sandbian stage (458Ma – 453Ma)
- Middle Ordovician (Llanvirnian) epoch (470Ma – 458Ma)
- Darriwilian stage (467Ma – 458Ma) (formerly Llandeilian)
- Dapingian stage (470Ma – 467Ma) (formerly Abereiddian/Llanvirnian)
- Early/lower Ordovician epoch (485Ma – 470Ma)
- Floian stage (478Ma – 470Ma)
- Tremadocian stage (485Ma – 478Ma)
Ma = million years (ago)