Geology
The base of the hill is formed from mudstones of the St Maughans Formation whilst the upper part is formed from the sandstones and mudstones of the Senni Beds Formation, both of which are assigned to the Old Red Sandstone laid down during the Devonian period. A few old landslides scar its slopes, a couple of which are seen to advantage from Castell Dinas and the ridge of Y Grib to the east. A number of small quarries have been worked on its slopes in the past.
Read more about this topic: Mynydd Troed