The fishermen also noticed a flaked blade made of a volcanic rock called rhyolite. When they pulled up their net, they found the partial skull of a mastodon, a distant cousin of the woolly mammoth that began its slide into extinction about 12,000 years ago, Stanford said.

'They hit a snag, or a hang, as they like to say, which meant that something pretty heavy was in their net,' said Dennis Stanford, an archaeologist with the Smithsonian Institution in Washington, D.C., who has analyzed the find. īut in 1974, a small wooden scallop trawler was dredging the seafloor, about 230 feet (70 meters) below the sea surface and nearly 60 miles (100 kilometers) off the coastline in the Chesapeake Bay. Artifacts from these ancient settlers, dubbed the Clovis culture after one of their iconic archaeological sites in Clovis, New Mexico, have been found from Canada to the edges of North America. Most researchers believe the first Americans crossed the Bering Strait from Siberia about 15,000 years ago and quickly colonized North America.

North sea trawlers dredging up mammoths