antarctic circumpolar current antarctica atlantic ocean bird bolca cambrian carbon dioxide carboniferous continent cretaceous devonian digital object identifier dinosaur drake passage eocene epoch flowering plant geology gondwana greek language gulf stream holocene humboldt current isthmus of panama jurassic last glacial maximum mesozoic messinian salinity crisis miocene neogene north america oligocene paleocene paleogene paleozoic permian phanerozoic pleistocene pliocene prairie proterozoic quaternary savanna silurian south america south pole tertiary wikimedia commons wikisource