en
2015-08-18 17:59 PM CEST
http://inspire.ec.europa.eu/codelist/GeochronologicEraValue/ludfordian:1
http://inspire.ec.europa.eu/codelist/GeochronologicEraValue/ludfordian
Ludfordian (older bound-421.3 +/-2.6 Ma, younger bound-418.7 +/-2.7 Ma)
IUGS /CGI value