Geograph - photograph every grid square

The slab near the centre of the photo is the underside of a siltstone layer in the turbidite sediments at the foot of Constitution Hill. The wiggly and elongated patterns are the filled-in imprints of worm burrows in the underlying mudstone layer, which has been eroded away. The worms would have been active in the topmost mud layer on the ocean floor when a turbidity current deposited sand on top of them, resulting in fossilised burrows after both the mud and sand layers were lithified.

The coastal stretch north of Aberystwyth towards Clarach is known for its exposed turbidite beds Link (Archive Link ) and for their intricate folding and faulting patterns Link (Archive Link ) . The name of the site originates from a sea stack located on the foreshore (links above are to the Geological Conservation Review's site reports).