Found a large chunk of rusty iron that had no regular shape. I left it where it lies because it was very, very heavy and wasn't about to haul it the half mile back to the car without the answer.
Fisher cz6a,,,Fisher cz-20,,,,Teknetics gamma 6000,,"Tek Eurotek pro ,,Fisher gold bug s.e 2.9er,,Tek T2 ltd se,,Tek T2+,,Minelab Vanquish 540 and 340 and a new Nokta Legend and Garret Infinium