Revision as of 19:52, 18 November 2009 by Proxima Centauri
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| Ordovician period|
| Early Ordovician|
| Middle Ordovician|
| Late Ordovician|
468 to 461 million years ago
The Darriwilian is the second and last age of the Middle Ordovician. It is defined by the first appearance of the graptolite Undulograptus austrodentatus at the type section in Changshan, Zhejiang Province, China.