Footprints recently discovered on the shores of a small island off the west coast of Canada may be the oldest in North America, researchers say. The find also bolsters a novel theory that the first inhabitants of the continent migrated from Alaska south along the coast by boat rather than inland on foot. However, the discovery has yet to be verified and published in a peer-reviewed journal.

A team led by University of Victoria archeologists Duncan McLaren and Daryl Fedje found a single footprint last year in the soft clay on the shores of Calvert Island, about 500 kilometers (310 miles) northwest of Vancouver. The researchers, backed by the Hakai Institute, returned a few months ago and dug up more footprints. These were determined to have belonged to two adults and a child seemingly huddled around a stone-ringed fire pit. Radiocarbon-dating of charcoal around one of the dozen fossilized footprints determined it is 13,200 years old. Additional samples are now being tested. “It was really quite exciting because with every brush of the trowel, you’d see toes appearing, or a heel or the arch of a foot,” McLaren told public broadcaster CBC. Locating evidence to support the theory that early humans traveled the length of the Pacific coast of the Americas by boat is challenging. Most coastal settlements, if they existed, would have been drowned by rising ocean levels caused by melting glaciers at the end of the Ice Age. Calvert Island is only reachable by watercraft, so it is reasonable to believe that whomever left the prints were seafarers, the researchers explained.