1,700 to 2,300 mya the middle of the Huronian Era in Precambrian time670 mya the end of the Proterozoic Era, in Precambrian time420 mya the middle of the Paleozoic Era, between the Ordovician and Silurian Periods290 mya the late Carboniferous and early Permian Periods, late in the Paleozoic Era1.7 mya the Pleistocene Epoch of the Quaternary Period (Cenozoic Era*mya-Million years ago
