Melvyn:
Years ago when we were first doing planning work at Archerfield, I suggested to John Ashworth that we ought to get a backhoe out there for a couple of days and dig some holes, just to make certain there wasn't rock or heavy soil close underneath that would spoil the budget for the project.
So we got a backhoe. The first couple of holes we dug were just sand, but on the third try we hit a big pile of rocks! And then another! It was actually like a seam of big stones about 100 yards inland from the beach. [Later, I found out that it was probably the old beach line from generations ago.]
Anyway, one of John's friends was very into Ley lines and natural energy fields and other odd subjects, and after we dug and hit the rocks the second time, he said he could tell us where they were by divining them. I was extremely doubtful, but I didn't want to dig 500 more random holes, so I pointed at the ground and asked what was right there, and he said the rocks were two feet deep ... and they were. I pointed about four more times, and he correctly told me if there were any rocks, and if so, how deep. So then I just used his advice after that, and found that the problem was fairly limited. I have no idea how he could predict any of it, but it worked.