1885, January: 300 Million Year Old Fossilized Human Prints Found
In January, 1885, a Mr. E.A. Allen wrote to the American Antiqurian to inform them of a recent discovery on Big Hill, part of the Cumberland Mountains in Jackson County, Kentucky. A trail over the hill was both anciently and modernly used; in clearing away dirt and leaves along a section of the trail Allen had exposed previously unknown fossilized footprints. The tracks were mostly made by bears, but there was also the prints of a large horse, and two prints that were very distinctly human.
In 1982, when the above account was reported in Reader's Digest's book Mysteries of the Unexplained, the editors added that the layer of rock the prints were found in was 300 million years old... but they don't give a source for this detail, and the original report doesn't include an estimated age.