 Finding sites associated with early coastal migrations is extremely difficult—and systematic excavation of any sites found in deeper waters is challenging and expensive.Strategies for finding earliest migration sites include identifying potential sites on submerged paleoshorelines, seeking sites in areas uplifted either by tectonics or isostatic rebound, and looking for riverine sites in areas that may have attracted coastal migrants.On the other hand, there is evidence of marine technologies found in the hills of the Channel Islands of California, circa 10,000 BCE.