We had an excellent day out at St Brides today, including picnic lunch on the beach. Naturally enough, I managed to do some geomorfin' while my wife searched for interesting pebbles, and I came away duly impressed. More of which anon -- but for a start here are some photos of the erratic boulders on the beach. They are easy to spot because the bedrock here is Old Red Sandstone -- and everything "foreign" is very prominent against the dark red background.
Finally, my wife's collection of interesting pebbles from the beach -- sandstone, rhyolite. flint, dolerite, granite, ash, quartz and some I don't recognize. Some of these are not very well rounded -- which means that they have been eroded out of the till at the head of the beach relatively recently.
When were these boulders transported and emplaced? Probably during the Late Devensian glaciation -- there is no reason to assume that they are older, although of course they might simply be "recycled" from older and pre-existing boulder beds or glacial deposits.