Archaeologists say two participants in a petroglyph seminar at the US Virgin Islands National Park have come across the first newly discovered rock carving there since the 1970s.
The carving looks like a spearhead or an elongated leaf.
Park archaeologist Ken Wild says the design is different from others on St John island.
"It's the type that's seen in Venezuela or St. Lucia" across the Caribbean."
His archaeological team say they believe last month's discovery is the work of settlers who came to the island of St John more than 2,000 years ago.