Late Ordovician epoch - Llandovery epoch
| International Chronostratigraphic Timescale | |||
|---|---|---|---|
| Silurian | Pridoli | 419.62 | |
| Ludlow | Ludfordian | 422.7 | |
| Gorstian | 425 | ||
| Wenlock | Homerian | 426.7 | |
| Sheinwoodian | 430.6 | ||
| Llandovery | Telychian | 432.9 | |
| Aeronian | 438.6 | ||
| Rhuddanian | 440.5 | ||
| Ordovician | Late Ordovician | Hirnantian | 443.1 |
| Katian | 445.2 | ||
| Sandbian | 452.8 | ||
| Middle Ordovician | Darriwilian | 458.2 | |
| Dapingian | 469.4 | ||
| Early Ordovician | Floian | 471.3 | |
| Tremadocian | 477.1 | ||
| 486.85 | |||