Kasimovian

The Kasimovian is a geochronologic age or chronostratigraphic stage in the ICS geologic timescale. It is the third stage in the Pennsylvanian (late Carboniferous), lasting from to Ma. The Kasimovian Stage follows the Moscovian and is followed by the Gzhelian. The Kasimovian saw an extinction event which occurred around 305 mya, referred to as the Carboniferous Rainforest Collapse. It roughly corresponds to the Missourian in North American geochronology and the Stephanian in western European geochronology.

extinction event; occurred ca. 305 Ma at the end of the Moscovian in the Carboniferous; altered the vast coal forests that covered the equatorial region of Euramerica, fragmenting them into ‘islands’, causing dwarfism and extinction of many species