The summit is very similar to that of Pen y Fan: flat and anvil-shaped. It is similarly formed from the relatively erosion-resistant Devonian age sandstones from the Upper Old Red Sandstone known as the Plateau Beds.
Similar to Pen y Fan in its flat, anvil-like shape, the summit is constructed from the same type of erosion-resistant sandstones: those of the Upper Old Red Sandstone, specifically the Plateau Beds.