people living on islands should be sufficient evidence of boats Historical sea levels were wildly different at different times, so not necessarily. For instanc

people living on islands should be sufficient evidence of boats Historical sea levels were wildly different at different times, so not necessarily. For instance, the British isles were settled at a point when it was a part of the mainland: https://commons.wikimedia.org/wiki/File:Doggerland.png https://commons.wikimedia.org/wiki/File:Doggerland.png