Горѿт Base of Ludfordian Stage Ludlow Epoch Gorstiën a1.1.3.4.2.2 Gorstian Age ゴースティアン期 Homerian Age Wenlock Epoch Ludfordian Age gorstiano older bound -427.4 +|-0.5 Ma gorsti younger bound -425.6 +|-0.9 Ma gorstij Gorstium Gorstium Gorsti Phanerozoic Eon International Chronostratigraphic Chart (2017) gorst gorst Paleozoic Era Gorstien Gorstien Gorst Gorst Gorst 格斯特期 Base of Ludlow Gorstian Gorstiano Gorstiense Silurian Period Gorstis