Not much like footprints, apparently.
Alleged footprints of early Americans found in volcanic rock in Mexico are either extremely old – more than 1 million years older than other evidence of human presence in the Western Hemisphere – or not footprints at all.
Earlier this year, British researchers believed they had found 40,000 year-old human footprints preserved in volcanic ash near a Mexican lake (New Scientist). If true, this would have changed our view of how and when the Americas were first colonised.
An investigative team of geologists and anthropologists from the United States and Mexico has rubbished the claims, after using other methods to date the rocks.