I often wonder about this in a difference sense. I would never detect in an actual graveyard or cemetery. However long ago when folks were scouting out areas they may have become ill or injured and died. Some of these people died without the benefit of a burial afterward especially if they were along. The wild animals are the Makers clean up crew. Bones and other parts got scattered as a result of this activity. Any rings or other jewelry and coins would have also been scattered. Bones and flesh decay and become the dirt they were made from. How do we know this isn't why that old ring is in the location we found it in. Even some of those who had the benefit of a hasty ground or rock burial could have suffered the same fate. I would hope the jewelry I found(should I ever find any) was not because some unfortunate settler/tracker/explorer died where he/she stood/sat.