I have to imagine someone involved in the fur trade dropped it. City it was found in wasn't founded until 1878 I believe. Apparently this is a coin from the British Guiana Colony in South America. In 1813 this One Stiver was minted while the colony was part of a conflict between the Netherlands, Britain, and France. In 1813, the One Stiver and the Half Stiver were minted to basically taunt the Netherlands by stamping King George III's face on it while still using the Netherlands currency. At least, that's what I've been able to gather so far.
Still can't believe I found this. Oldest coin previously was a 1902 Barber dime.