THE CORROSION ON LEAD IS VERY DIFFERENT FROM THAT ON SILVER SO AT LEAST THE OUTER COATING WITH THE MARKS AND SUCH ARE SILVER. IF LEAD IS IN THE CENTER THEN PERHAPS SOMEONE STOLE THE REAL SILVER INGOT AND MADE UP THIS ONE BACK IN THE DAY. IN SUCH A CASE PERHAPS THE FAKE INGOT COULD HAVE BEEN SECRETELY THROWN OVER THE SIDE WHEN SALVAGE WAS BEING DONE BY THE THIEF OR THIEVES SO THEY WOULD NOT BE FOUND OUT. THINGS OF THIS SORT HAVE HAPPEND SO IT IS A POSSIBILITY IF INDEED THERE IS LEAD PRESENT. A TREASURE HUNTER AND SCHOLAR OF ALL THINGS PIRATE AND TREASURE WOULD BE ABLE TO TELL. SHIPWRECKS AND PIRATES AAAARGH !
