Are these ancient SURVEY Marks?
Archaeologists in Saudi Arabia have found ancient monuments that look remarkably like giant survey reference marks pointing towards a central monument. As a surveyor who has retraced old Coast and Geodetic Survey marks, I recognize the use of arrows on reference marks to point towards and perpetuate a central control mark. According to this article, https://www.cnn.com/2018/06/20/middleeast/saudi-archaeology/index.html, the experts don't yet understand what the rock cairns mean, but believe them to be thousands of years old. I imagine the same might be said today of some old survey monuments we recover without any record of who set them or why they were set. Keep on leaving those "footprints" - you never know who might be following yours.