It includes the peaks of Craig Cerrig-gleisiad (629 m: SN960217) and Fan Frynych (629 m: SN958227). Craig Cerrig-gleisiad means 'cliff of the salmon(-coloured) rocks' and is a cirque formed by a glacier which deposited moraine and created a sheltered environment where the steep crags prevent sheep from accessing the rare Arctic–alpine plants such as purple saxifrage and roseroot and mixed woodland where orchids and anemones flourish. There is scattered scrub woodland and scattered hawthorn on the lower slopes.