Coast Walking (Wales): Ogmore to Llantwit Major 26 May 2016

Carboniferous limestone cliffs

Sheep pasture

Ammonite impression in limestone boulder

Parking at the far south of Ogmore-by-Sea, we walked 100m back down to the coast path and continued east, the whole day along the top of fairly low cliffs, the plants unremarkable with agricultural land bordering us inland – sheep pasture and arable. The shore platform was of Carboniferous limestone (e.g. Black Rocks), initially with Recent blown-sand cliffs above, latterly steeper with cliffs also of limestone. We came down into Dunraven Bay, but the tide was high. There is a Heritage Centre for the Glamorgan Coast, where we bought a geology of the area for future reference. There were also well-timed toilets for relieving over-indulgence in breakfast coffee. A small artificial pond contained Curled Pondweed. This “Heritage Coast” is quite scenic, although no Pembrokeshire or Gower. Various paths led up the slope opposite, where there are stone remains of a fort on the headland of Trwyn Y Witch or Witches' Point, composed of Liassic Sutton Stone overlaying the Carboniferous limestone. A series of descents-and-rises at streams entering the sea followed at intervals, but none too exacting. From Cwm Mawr to Cwm Bach, Blue Lias cliffs replace those of the Carboniferous limestone, as briefly happens also at Cwm Nash. They are distinguished by their pale colour compared to the dark Carboniferous limestones (as at Black Rocks). At field edges Musk Thistle was common, just coming into flower, while Woolly Thistles were identifiable from their distinctive leaf-rosettes. Occasionally Choughs were seen and heard. The next accessible cove was at Nash Point, where we descended into the cove from the coast path, both to take some lunch and to explore the beach. Sheer cliffs of Blue Lias rise high here, composed of conspicuous bands of sandy-coloured limestones interbedded with softer shales, which weather to produce regular rock falls. These had affected the coast path coming here, as it is continuously having to be re-routed further from the crumbling edge. The top of the beach is composed of rough or sea-worn limestone boulders, many with fossils of shells and ammonites. Below these is a flat shelf of limestone that makes very easy walking. Herring Gulls and Jackdaws nested on the cliffs, which exhibit frequent faulting. The jackdaws were omnipresent to sight and sound today from our start to the very end. Much of the way, too, the cliffs were notable for abundant Wild Cabbage. As the day warmed up with continuous sunshine, butterflies became increasingly prevalent, especially (no doubt as a result of the cabbage) the Whites (Large and Green-veined). Just after Nash Point were two lighthouses and a foghorn, now disused except for announcing weddings! The cliffs now started to become much lower. At St Donat’s Bay there was a concrete walkway at the front but there was no access to the castle and its grounds, now a college. There were clumps of stinking iris here. The next bay, Tresilian, was notable for the large pebbles we had to negotiate to cross the beach, made even more difficult by a colony of Japanese Knotweed! The cliffs here have a number of sea-caves (e.g. Reynolds Cave), whose ceilings are protected by a particularly hard band of limestone. After Tresilian a projection of sand and rocks at shore level replaced the usual flat rock shelf and demarcated the cove below Llantwit Major. Celebratory ice-cream in hand, we left the coast path here to walk 1½ miles up a very wide green valley which was white on the side-slopes from flowering Hawthorn, to the bus station and transport back to Ogmore.