482 - 470 Ma

The definition of this interval in the timescale Ordovician of North America is taken from the following source:

• W. B. Harland, R. L. Armstrong, A. V. Cox, L. E. Craig, A. G. Smith and D. G. Smith. 1990. A Geologic Time Scale 1989. view

The bottom age has been interpolated based on the differences between the ages for international timescale boundaries quoted in the source and the currently accepted ages for those boundaries.

There are intervals in 8 timescales which overlap this one. show

• International Chronostratigraphic Timescale: Early Ordovician epoch, Floian age, Tremadocian age
• Ordovician of Britain: Tremadoc epoch, Whitlandian age, Moridunian age, Fennian age, Cressagian age, Migneintian age, Arenig epoch
• Ordovician of the Baltic: Oeland epoch, Hunneberg age, Langevoja age, Varangu age, Hunderum age, Billingen age, Valaste age, Latorp age, Saka age, Vaana age
• Ordovician of Ibero-Bohemia: Klabava age, Arenigian age
• Ordovician of Australia: Chewtonian age, Bendigonian age, Lancefieldian age
• Ordovician of China: Ningkuo age, Hunjiang age, Yiyangian age, Xinchangian age, Dawan age, Lianghekou age, Daobaowan age
• Ordovician of North America: Gasconadian age, Jeffersonian age, Stairsian age, Blackhillsian age, Tulean age, Ibexian epoch, Canadian age
• Cambrian of Kazakhstan: Ungurian age

This interval is no longer in current use

This interval is used in the definition of 268 collections

A total of 3757 collections with 18280 occurrences lie within this time span