The research began with the 2015 discovery of what is believed to be a Clovis point arrowhead, which Gramly says could be 12,800 or more years old and worth as much as $15,000.

Experts consider the Clovis to be among the first Americans. Stanford says the artifact is “a classic Clovis point”, dating from 13,500 to 14,000 years ago and made of a silicate, probably jasper.

Noah Cordle, 10, found this Clovis point on a New Jersey beach this summer. Cordle this week donated the artifact to the Smithsonian Institution's National Museum of Natural History.