Celtic inscriptions dated to the 480-720 AD era are atop several mountains in West Virginia Assuming the inscriptions were in stone, how is such close dating done with no radio carbon, decomposition or similar things to place it in time?
By the alphabet and language written (Celtic), and by what the message said. It was Christian, and told them how to calculate the dates for Christmas, and told of Christ's having been born of a virgin at Bethlehem.
At least one whole issue in the 1980s of Wonderful West Virginia was about this.