Summary: in the USA, the person who found it absent whoever put it there. If you can prove you put it there, you can have it back, but otherwise it seems to be the finder's. There doesn't seem to be any law about it, just case law.
Seriously, hope someone is willing to tackle this hypothetical scenario:
Land owners are unaware of a buried cache of gold that was robbed from an armored car in the prohibition era...
And it has to be dug up.
The spot is marked with a stack of large rocks. The previous owners were ostensibly always deterred by the threat of blasting caps being buried on top of it.
What would you do about that? Anything?
Edit: Offer to split it with the land owners, and call the excavators? (and the bomb squad?)
