Would a couple glasses of stout and mild help any, just kidding, It sure looks to be something connected with surveyor and Church property, my thoughts are you are looking at a map of Church / Government property, I would start with the 4 directions and Google Earth, If the boxes are property indicator's each one could = 2.5 miles. I would start by going East first then North / South Looks like may be 25 miles wide ( kinda interesting that its similar to the Township method that they may have used in the U.S. ) It seems that there no information on the back side and looking Toward the East then to the Left and to the Right seems to be Three directions followed, Looks to be the 1800,s which It may belong to the Church, the marker you show may be on the South property line, it looks to the East then the two directions left would be North and South, All of the corners that I have found seem to be in the South East corner that had Information on them.