This is the entry into the St Erth Clay Pits explained on the plaque outside the Star Inn. This was once part of an inlet of the sea which separated West Penwith from the mainland. Fossils, a rarity in Cornwall, were discovered in the clay. Geological pressure on sedimentary rock turned this into a clay utiliased as a pits not so long ago. Bernard Leach was fond of this clay for his pots.
