That in the 1800's the used stones to mark corners of property lines. These are called corner stones and tended to be rocks that they buried a couple of feet in the ground. In more rural areas in the midwest there are still properties where these exist. So you do your research and your math then to to find the approximate area where you think the stone is buried. Then you dig a hole and start looking. Now they use pieces of rebar with plastic caps on them. Tend to be a lot easier to find with a metal detector.
That in the 1800's the used stones to mark corners of property lines. These are called corner stones and tended to be rocks that they buried a couple of feet in the ground. In more rural areas in the midwest there are still properties where these exist. So you do your research and your math then to to find the approximate area where you think the stone is buried. Then you dig a hole and start looking. Now they use pieces of rebar with plastic caps on them. Tend to be a lot easier to find with a metal detector.