Ordovician
Period ranging from 488 million years ago until 444 million years ago.
In the Ordovician period there were many trilobites and graptolites. Several mollusks developed. The number of species of primitive fishes and (sea)plants increased. Brown, red and green algae developed. First fishes with a developed skeleton and muscles. At the end of the Ordovician period there is a mass extinction.
Period
| Epoch
| Stage
| Age (in Milion years) *
| 
| Upper
| Hirnantian
| 444 - 446
|
| 446 - 456
|
| 456 - 461
| Middle
| Darriwilian
| 461 - 468
|
| 468 - 472
| Lower
|
| 472 - 479
| Tremadocian
| 479 - 488
|
* Age is rounded
Click here for locations from this period.
 Go to the Photo page to view photographs of fossils from the Ordovician. |
