The Screes are a Site of Special Scientific Interest and are regarded as a classic geological locality and one of the best and most famous examples of screes in Britain. The escarpment and screes are made up of hard wearing Borrowdale Volcanics rock, however there are areas of less resistant rock which have been eroded and this has led to deep gullies in the cliff face. The cliffs around the summit of Whin Rigg take the form of vertical rock buttresses which are split by the huge Great Gully and C Gully which give precipitous views of Wast Water. The gullies are spectacular but are a no go area for walkers, Great Gully has seventeen near vertical pitches and the remains of an aeroplane within it.