Last Sunday I posted a little question where was I when I took the photo. I thought the hill would be a giveaway but for once no one came close. Further back and a little bit higher on the edge of Urra Moor and Hasty Bank becomes more obvious. The valley is the top end of Bilsdale and is 90º to the B1257 which continues to climb up to the col at Clay Bank. So I guess this small wooded sided valley is still actually Bilsdale as Bilsdale Beck flows down it. But on large-scale maps, it is referred to as Rotten Scar.
The two clues were entirely my own fanciful inventions but were inspired by accepted derivations of other place names. The ‘scar’ of Scarborough does indeed come from the Old Norse word skartð for a notch or harelip. I do think a notch describes the small valley better than a scrappy line of crags. ‘Rotten’ being descended from rother, an archaic word for cattle, has actually been suggested as an explanation for Rotten Row in London. I saw the valley as an ideal place for corralling cattle.