Crag and tail. Nov 16, 2021 · Crag is a mass of hard rock with a steep slope on the upward side, which protects the softer leeward slope from being completely worn down by the oncoming ice. . It therefore has a gentle tail strewn with the eroded rock debris. The tail in this type consists of bedrock. A crag and tail is distinguished from a roche moutonnée by the presence of an elongate, tapered ridge of till extending downstream. Erosional crag-and-tails consist of a highly resistant rock crag that protected less resistant bedrock in its lee from the full force of glacial erosion. Nov 29, 2008 · A crag and tail is a larger rock mass than a roche moutonnee. Often produced by selective erosion of softer strata, roche moutonnée landscapes are characteristic of glaciated crystalline shield areas. Frequently the crag serves as a partial shelter to softer material in the wake of the glacier, which remains as a gradual fan or ridge forming a tapered ramp (called the tail) up the leeward side of the crag. Like a roche moutonnee, it is formed from a section of rock that was more resistant than its surroundings.