Quoted from OLDPINGUY:The amount of material pre 1600, and in theory 1400s, is amazing!
One theory, I can think of, is the 1492 Expulsion of 200,000 Jews from Spain.
Many went by boat, and some ended up south of US, in the Island of Granada that is known.
Yes, within 1 day of Columbus, but thats another story.
Who knows if a ship went north? They feared persecution, and could have buried the wealth they took.
Or maybe people kept things in working order forever back then. And the tools were made well and lasted longer. So a 1400's tool was still used in the 1800's when it was dropped. Could it be?