Triassic conglomerate at Black Rocks near Porthcawl

 Walking along the beach from Newton towards Merthyr Mawr I found this rock that looks amazingly like concrete in the Black Rocks formation on the beach.

This map confirmed that it is Triassic. I then found this walk leaflet that explains what happened, even though the walk described is in the other direction from Porthcawl. It seems that Carboniferous limestones were eroded and washed down with sand to form a conglomerate. A similar thing happened in the Eden Valley up here. The pebbles seem quite rounded so must have been transported some distance.