Hello Tom, Generally when I find a carvings such as the ones you posted I have found using the X as the 4 directions, the small triangle in the lower upside down V may what you will be looking for laid out with boulders, if the holes are natural its possible that it indicates a trail, 1 hole may indicate 1 league, I doubt that its native American, some may think Norsemen, Spanish, some may think the other carvings are those that you will find along the trail. The carvings should be about 200 feet apart ( Cordel 189.5 feet ) Keep in touch.