I have seen that kind of marking twice before. Once on the eastern shore of Virginia and once in the southwest Virginia mountains. The one in the mountains is in black bear territory so I always assumed it was a bear. We had them on the mountain that year as they had been up all the wild cherry trees tearing the tops out to get the cherries.
The one on the eastern shore was puzzling as there was a Ranger there who said there were no bears on the eastern shore. I hope you figure out what it is as we never figured out for sure what made those marks we found.