Ordovician Period By 14crowleyj Period: Jan 1, 1964 to Jan 1, 2011 Ordovician time period Apr 26, 1964 Glaciation of Gondwana Apr 26, 1965 Nautiloids Apr 26, 1965 Brachiopods Apr 26, 1966 Hirnantian Apr 26, 1968 Soil Formation Apr 26, 1970 Cryptospores Apr 26, 1971 Katian Spore threads Apr 26, 1971 Start of Andean-Saharan ice age Apr 26, 1971 Pteraspidomorphi early to late Apr 26, 1972 Crinoids Apr 27, 1975 Brachiopods Apr 27, 1976 Echinoderms Apr 26, 1981 Sandbian Apr 26, 2009 Gondwana moving over South pole Apr 26, 2010 second largest mass extinction of all time Wiped out almost half of all marine life
