<P> This is a selected list of the oldest rivers on Earth for which there is knowledge about their existence in past times . </P> <P> Generally, the age is estimated based primarily upon the age of any mountains it dissects; the age of the sea or ocean to which it eventually outflows can be irrelevant; for example, several rivers of the east side of the Appalachian Mountains of the Atlantic Ocean, which did not exist 130 million years ago . If a river fully dissects a mountain range, then this generally indicates that the river existed at least at the time that the mountain range rose . </P> <Table> <Tr> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Th_colspan="6"> Continent color key </Th> </Tr> <Tr> <Td> Africa </Td> <Td> Asia </Td> <Td> Oceania </Td> <Td> Europe </Td> <Td> North America </Td> <Td> South America </Td> </Tr> </Table> </Td> </Tr> </Table>

How to determine the age of a river
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