I have a question about how to attach a fence post to the top of a rock wall. The rock wall is on my property line and I would like to fence in my yard, but I don't know how to attach the post to the wall. I would set in the fence from the wall, but there are two large trees in the way which would break the line of fence because they are right next to the wall. The wall is about 30 feet long and goes from 6" to 3' in height. I think I will move the rocks and pour a footing in the shallow locations, but where the wall is 3' high, I am not sure what to do. I don't think I should remove all of the rocks down to the ground just to add a post. What should I do?