Quite a few of these were heading out to forage on the sand at low tide. The 1st photo shows a track behind the animal, indicating it is in motion. The 3rd photo shows how many were on the move, and the 4th a few stay-at-homes still adhering to their rock (along with the smaller Bembicium nanum, if that's still what the little conical winkles are called). I assume they would all have been back on the rocks by the time the tide came in again, which would have been a fair hike.
Washed up at Fairhaven Beach