Which geological period is named after an ancient tribe which once inhabited South Wales?
Silurian period Ludfordian Lower Silurian Silurian System Llandovery epoch Early Silurian Upper Silurian Ludlow epoch Silurian climate Silurian system Gorstian Aeronian Pridoli epoch Silurian Era Telychian Rhuddanian Late Silurian Rhuddalian Ontarian stage Silurian Period Silurian Přídolí epoch Llandovery Series Silurian era