The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species Undulograptus austrodentatus around 467.3 million years ago. It lasted for about 8.9 million years until the beginning of the Sandbian around 458.4 million years ago.
The GSSP of the Darriwilian is the Huangnitang Section ( ) near the village Huangnitang, 3.5 km southwest of Changshan County Town (Zhejiang, China). It is an outcrop of the Ningkuo Formation, consisting of mainly black shale. The lower boundary of the Darriwilian is defined as the first appearance datum of the graptolite species Undulograptus austrodentatus in that section.
The base of the Darriwilian is also the base of the Undulograptus austrodentatus graptolite zone. This zone lies just above the North Atlantic Microzarkodina parva conodont zone. The base also lies in the upper part of the North American Histiodella altifrons conodont zone.
|Agnathans of the Darriwilian|
|Dapingian-Sandbian||Sacabamba, Cochabamba Department, Bolivia; Horn Creek Siltstone, Australia; Argentina; Oman|
|Endocerids of the Darriwilian|
|Dapingian-Darriwilian||Chazy Reef Formation, New York, USA|
|Dapingian-Darriwilian||West Spring Creek, Oil Creek Limestone, Oklahoma|
- "GSSP Table - Paleozoic Era". Geologic Timescale Foundation. Retrieved 30 November 2012.
- "GSSP for Darriwilian Stage". Geologic Timescale Foundation. Retrieved 30 November 2012.
- Mitchell, C. E.; Chen Xu; S. M. Bergström; Zhang Yuan-dong; Wang Zhi-hao; B. D. Webby; S. C. Finney (1997). "Definition of a global boundary stratotype for the Darriwilian Stage of the Ordovician System" (PDF). Episodes. 20 (3): 158–166. Retrieved 20 September 2012.[permanent dead link]
- Gradstein, F. M., ed. (2012). The Geologic Time Scale 2012. Elsevier Science Ltd. p. 1176. ISBN 978-0444594259. Retrieved 30 November 2012.