Footprints left in wet clay around 13,000 years ago by two barefoot adults and a child were recently unearthed by anthropologists on Calvert Island in British Columbia, Canada - the oldest known human track marks in North America, and more evidence that humans were on the Pacific Coast toward the end of the last ice age. The island is about 100 kilometres north of Vancouver Island.
     About 11,700 years ago the North American Cordilleran Ice Sheet ended along the Pacific coastline, leaving iceless areas where plants and animals could survive. Calvert Island was one of these, with sea levels 2 to 3 metres lower than now.
     The first footprint appeared about 60 centimetres below the beach during excavations in 2014. Two pieces of wood found by the footprint were radiocarbon dated to between 13,300 and 13,000 years ago. Researchers returned to the island during the 2015 and 2016 field seasons, eventually uncovering 28 more human prints from the same period. The 29 prints have clear arch, toe, and heel marks.
     The oldest documented site of prehistoric people along the west coast of North America is Manis Mastodon, on the Olympic Peninsula of Washington state, in the northwest USA. There researchers found a bone point embedded in a mastodon rib dated to about 13,800 years ago. The oldest known human habitation site in Canada is younger - a group of artefacts including a stone weapon found at Charlie Lake Cave in British Columbia dates to about 12,500 years ago. Similar radiocarbon ages were found in association with a lithic assemblage at the Vermillion Lakes site in Alberta.

Edited from PlosOne, LiveScience, The New York Times (28 March 2018)