X marks the spot

I'm doing some surveys in a town I wasn't very familiar with until this year. I've worked all around it in the big country but not much in town. I was surprised how many of these we're finding:

That isn't a thing I'm used to seeing. I was talking to one of the local surveyors and he said, yep those are mine I set when I first started out, the shop was too cheap to even rent a drill. Good thing is they won't be there much longer.