In "The Devil and Tom Walker", where was the buried treasure that the Devil presided over said to have come from?
The origins of the treasure are identified in the first pages of the story; it is said to have been hidden by Captain William Kidd, a famous real-life pirate and privateer who had dealings with the New England colonies and was famous thereafter for stories of buried treasure.
The treasure is said to have been buried at a conspicuous natural formation on the coast of Massachusetts; an inlet (like a small bay) with a rising promontory on one side (like a small set of hills or cliffs) that made for a good lookout spot as well as being easily recognizable by those who mean to look for it (such as Kidd, had he ever returned for the treasure). The treasure is said to be in the Devil's care not only because Kidd specifically bargained for it to be so, but because the Devil normally presides over the burying of treasure, particularly when it is stolen.
The exact nature and composition of the treasure is unstated; normally presumed or implied to be gold, treasure secured by pirates and privateers of the period might have included gold and silver coins and bars, jewels and jewelry, as well as trade goods such as silk and manufactured items.