What came first a boat or a wheel?

Information garnered from Wikipedia: Most authorities estimate that the wheel originated around 5000 BC. The earliest depiction of a wheel in use (as a wagon) is on a clay pot from modern-day Poland dating from 3500 BC. Circumstantial evidence suggests boats have been around many thousands of years (ie the colonization of Australia by Aborigines, however the earliest archeological evidence of boats dates back between 5500-7000 BC. It appears that boats came first.