🌐EnglishEnglishDeutschEspañolFrançaisItalianoNederlandsPolskiPortuguêsSvenskaTiếng ViệtTürkçeРусскийالعربيةไทย한국어中文日本語EntityQ502892· pop 29index fossilfossils used to define and identify geologic periodsAvailable in 29 languagesEspañolFrançaisDeutsch中文日本語РусскийPortuguêsItalianoالعربيةBasqueBelarusian