I'm digging in a park yesterday behind a 1920 swimming pool next to a river and I found one billion square head large nails that my SE kept calling silver dollars (top right side of discr screen) they were all about 8-10 inches deep and i kept finding a layer of black ash about the same depth. Did I locate an old burned down homestead? and why does my SE keep calling 6-8 inch bent rusted nails silver coins with no ferrous content and high cond? How do I eliminate this so I can find coins? or should I be more concerned with finding relics, I only found these nails by the way.