Tracks left along an ancient shore by a man, a woman, and a child on a remote island off the coast of British Columbia may be the oldest known human footprints in North America.
     A dozen prints, in three distinct sizes, were discovered by researchers working on Calvert Island, a coastal isle in Canada's Great Bear Rainforest that has yielded other evidence of human activity dating to the end of the last Ice Age.
     The first of the footprints was found last year, filled with black sand and traces of charcoal, a sample of which was radiocarbon-dated to 13,200 years ago.
     The find adds to evidence that the first people didn't arrive in the Americas via an ice-free corridor east of the Rockies about 12,000 years ago, but down the Pacific Coast much earlier. In recent years, archeologists have steadily been pushing back the date of the earliest human presence on the Pacific Coast.
     The newly found prints were unexpected, but such ancient evidence of human activity is not unheard of on Calvert Island.
     Dr Duncan McLaren, of the University of Victoria said: "We were specifically looking for archaeological deposits dating between 14,000 and 10,000 years ago" - artefacts such as stone tools and bones. Based on our sea-level history work, we know that the shoreline was a few meters below the present shoreline during this period. So we began testing in the intertidal zone in front of [the] archaeological site ... to see if we could find any intact deposits beneath the beach."
     The discoveries will likely provide insights into the earliest settlement of British Columbia, and perhaps the peopling of the Americas. "The oldest dated archaeological assemblage known before this is from Haida Gwaii, where a spear point was found in amongst bear bones in a cave, dating to around 12,500 years before present," McLaren reveals. "As far as I know, archaeological deposits from the ice-free corridor are not known before 12,500 years ago."

Edited from The Globe and Mail (22 June 2015), Western Digs (26 June 2016)