Rock detail, Bøverdalen

Going through images I shot this summer I found this image. I had almost forgotten about it. On my way through Bøverdalen I came across some huge boulders a kilometer or so from Krossbu. I stopped and shot a few frames from different angles. This is the last frame in the series, and looking at it again I spotted a detail I had overlooked at first. I have worked a little with light and contrast to emphasize it slightly. See if you can spot it.