For example, scientists working a settlement site in southern Chile have unearthed what they interpret as stone-cutting tools, one of which had small particles of seaweed on the blade, according to research published Thursday in the journal Science.
The site, dubbed Monte Verde II and increasingly acknowledged as the oldest settlement in the Western Hemisphere, lies 55 miles east of the coastline of that time.
The team, led by Vanderbilt University archaeologist Tom Dillehay, found several species of seaweed, including five species they hadn't seen there before. In addition, they found algae that normally grows on trees and rocks along the coast. The seaweed specimens were found in soil from the floors of a what scientists think was a residential and a medicine hut.
The seaweed samples are between 13,980 and 14,220 years old. The oldest Clovis sites, by contrast, are some 13,000 years old.
The finds have some intriguing implications, Dr. Dillehay says. The variety of plant, seaweed, and animal remains found, along with the site's riverside location, suggest that the Monte Verdeans had lived there long enough to develop a detailed understanding of the range of food and medicinal resources available to them from the coast well into the mountains. That could imply that early immigrants moved south far more slowly than some have suggested – coming to terms with their current location before moving to another one.
Just as intriguing, he says, is plant material found, native to Patagonia, on the eastern side of the Andes. "So, they're cutting through the mountains into the dry steppes of Argentina," he says. "That could happen as a result of long foraging trips."