This hole/depression right alongside the "mail road" almost looks like somebody did a little digging for some purpose of other. Actually, it's not man-made. It's a buffalo wallow. They like to scrabble around and by rolling and scratching themselves they dig these wallows all over the countryside. Fresh ones were "good sign" for Indians in the old days, and not a few frontiersmen found them to be excellent emergency breastworks for defense against a surprise attack.