In a dense, wooded lot, 17-year-old Justis Jackson lies on a mound of dirt. He doesn't seem to mind the sticky heat or buzzing mosquitoes. Jackson's attention is fixed on a buried object at the bottom of a neatly dug hole.
"Sounds like metal," he says, knocking. "But what type of metal and how old it is, I don't know. I hope it's old."