Coin,
If you don't mind research, look into Black Bellamy's fort and treasure vault. Bellamy and his partner, Paul Presgraves, were two very successful pirates. Their most famous take was the Wydah (now being salvaged) but they had dozens of smaller takes. They had a fort on the Machias River (location now lost) and a vault either inside the fort or just outside. ( I tend to believe inside, who would hide their money where it could be taken while you are defending the fort.)
Check into old maps and diaries. Possibly newspapers (but I wouldn't count on much there)
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grizzly bare