A slightly different version, from Ruth Tongue’s ‘Somerset Folklore’, and heard from a gardener in Corfe. The ‘Digital Digging’ website confirms that the site is known as ‘Castle Rache’ locally, with the topmost bit being ‘the Beacon’.
There was a vast treasure hidden on Castle Rach, and it was guarded by devils; but the men of Corfe were both valiant and poor and they determined to dig it up. They went to the priest and he promised to come with them, bringing some salt and holy water. The church bells were rung to drive away the devils and the digging began. It was highly successful. So vast a treasure did their spades uncover that one man swore in sheer surprise. At once the chest sank out of sight, the devils came back and every man, including the priest, died within a year.