These stones were from our farm and we made interest about treasure hunting stuff. To those treasure hunters who want to work with us, just contact these numbers: 09078251908 or 09352102738
The fourth photo is very typical of what a survey monument marker looks like, a square rock with a X inscribed into the surface. Most of the other holes just look like water indent wear holes.
The stone in the first pic. looks like there is carving all over it not just the compass in the circle. Why don't you do the rubbing a pincil over a sheet of paper on the whole thing? Good luck.