My grandad used to find gold and silver Spanish coins around st Augustine Florida , usually he would go after a big blow. he said it stirred up the beach and brought coins up. he detected the out lying Islands too around there. st Augustine is the oldest European city in north America , started by the Spanish in the 1500's . It was their headquarters and banking center for the new world . all the gold ships to pay the troops, workers etc came though the bank at st Augustine. the original fort and bank still stand at st Augustine . with a smaller fort just a bit north of the big one. Its on the intercoastal waterway. also there was a large wooden fort at middleburg Florida, inland from st Augustine, that was later abandoned due to the out break of yellow fever there. It was, I believe supposed to be on a fork on the black creek. the original site was never found but very much known to exist. there are Spanish records of it. I remember my grandfather even being able to get a map from somewhere and a description of where it was supposed to be. good luck hope ya find something.