|
|---|
| 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 | Ashgill | Hirnantian | 443.1 |
| Katian | Rawtheyan | 445.2 |
| Cautleyan | 448.8 |
| Pusgillian | 449.2 |
| Caradoc | Streffordian | Onnian † | 449.5 |
| Cheneyan | 451.3 |
| Burrellian | 452.5 |
| Sandbian | 452.8 |
| Actonian † | 453 |
| Marshbrookian † | Woolstonian † | 454 |
| Longvillian † | 455 |
| Aurelucian | 456.6 |
| Soudleyan †/Harnagian/Costonian | | 457.2 |
| Middle Ordovician | Darriwilian | Llanvirn | Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn | | 458.2 |
| Abereiddian/Early Llanvirn | 461.1 |
| Arenig | Fennian | 468 |
| Dapingian | 469.4 |
| Whitlandian | 470.7 |
| Early Ordovician | Floian | 471.3 |
| Moridunian | 473.8 |
| Tremadocian | Tremadoc | Migneintian | 477.1 |
| Cressagian | 481.1 * |
| | 486.4 * |
| 486.85 |