Okay. So this story isn't precisely about the Woodbarrow. But I'm inclined to think that Westcote's vagueness about its location is all part of his storytelling style.
The name of this other burrow I remember not, but it is near another that I cannot forget, Wood-burrow, of which a gentleman worthy credit, both for honesty and wealth (as the proverb saith worth a 1000£), told me this relation.--
Two good fellows, not inhabiting far from this burrow, were informed by one who took on him the skill of a conjuror, that in that hillock there was a great brass pan, and therin much treasure both silver and gold, which if they would mine for, he promised (by his metaphysical skill) to secure them from all danger, so he might have his share with them. They with little persuasions assented, and in love made a fourth man acquainted therewith, whom they knew to be no dastard, but hardy in deed; but he better qualified than to take such courses to purchase wealth, absolutely refused to partake therein, but promised secrecy.
The other two, with their protector the mystical sciencer, proceed, come to the place, go to their work, and apply it so earnestly that long it was not ere they found the pan covered with a large stone; with a sight whereof and their assister's encouragement they follow their labour with the utmost ability, for he always told them if they fainted when it was in sight it would be soon gone and taken from them, and their whole labour lost.
Now the cover was to be opened, and the fellow at work; but he was suddenly taken with such a faintness that he could neither work nor scarce stand, and therefore called to the other to supply his place, which he presently did. Lifting up the cover he was instantly surprised with the like faintness; which continued not long with either; but their defender told them the birds were flown away and the nest only left, which they found true; for recovering their strength they lift away the stone and take out the pan, wherein was nothing at all but the bottom thereof, where the treasure should seem to have been, very bright and clean, the rest all eaten with cankered rust.
The relator protested that he saw the pan, and they two that laboured told him severally all these circumstances, and avowed them.
Quoted by Grinsell from Westcote's 'View of Devon in 1630', in
The Archaeology of Exmoor
L V Grinsell
S Toulson* describes how John Knight (someone who was determined to turn Exmoor into useful agricultural land and metalled lots of roads in the early 19th century) used the Woodbarrow to mark the end of his estate. It's actually on the boundary between Devon and Somerset.