Rising sea levels destroyed evidence of shell middens at many prehistoric coastal sites
(PHYSorg.com Archaeology & Fossils)

Archaeological remains of coastal occupation in the form of shell middens are commonly found on today`s shorelines, and evidence for shellfish as a food source goes back 164,000 years. Within this time frame, sea-levels changed dramatically and shorelines moved on the scale of kilometers. The current study, published in PLOS ONE, reveals that this movement of coastlines impacted the majority of shell middens by causing shells to wash away or to currently be underwater, and thus has skewed our understanding of past coastal subsistence around the world.