The interval definitions in this timescale are derived 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

There are 5 timescales which overlap this one. show

• Obsolete Names for ICS Units
• Ten Million Year Bins
• Silurian of the Baltic
• Silurian of England
• Silurian of North America

Interval boundaries marked with * have 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.

This timescale is used in the definition of 11 collections