Definition: A blunt-ended, sloping ridge which descends the flank of a valley. Its abrupt termination is normally due to erosion by a glacier which tends to follow a straighter course than the former river.
Ice flowing from N-S down the valley now occupied by the Rackwick Burn has not only deepened the valley, it has widened it too. The cliffs of Grut Fea and Clicknafea truncate preglacial valley spurs and give way downslope to scree. It is noteworthy that these cliffs occur on the outside of a broad bend in the valley where the moving ice would have been forced against the hill slope.