 It is largely composed of broken Old Red Sandstone and has been interpreted as either a glacial moraine or as a pro-talus rampart.The peak is within the Fforest Fawr Geopark designated in 2005 in recognition of the area's geological heritage.The escarpment overlooks a famous Welsh stone circle, Cerrig Duon (or black stones) which are likely of British Bronze Age date, although it has never been excavated scientifically.