Silurian

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151	PDF Document Add to Reading List Source URL: fossilinsects.net Language: English - Date: 2007-09-20 09:04:44 Paleozoic Eurypterid Dolichopterus Acutiramus Hughmilleria Dolichopteridae Onychopterella Erettopterus Silurian Eurypterida Geologic time scale Phanerozoic
152	Untitled Add to Reading List Source URL: acdb-ext.gsfc.nasa.gov Language: English - Date: 2009-12-30 15:02:33 Gamma-ray burst Ordovician–Silurian extinction event Extinction event Supernova Ordovician GRB 970228 Gamma-ray burst emission mechanisms Astronomy Space Nature