This is a documentation subpage for Template:Period id. It may contain usage information, categories and other content that is not part of the original template page.

This template is used on approximately 24,000 pages and changes may be widely noticed. Test changes in the template's /sandbox or /testcases subpages, or in your own user subpage. Consider discussing changes on the talk page before implementing them.

This template is used by other Geological period templates for preprocessing of period names. It performs a conversion to lowercase and substitution of synonyms.

((Period id|period name))

((Period id|Late-Cretaceous)) → upper cretaceous