Tafoni (singular: tafone) are small cave-like features found in granular rock such assandstone, with rounded entrances and smooth concave walls. They often occur in groups that can riddle a hillside, cliff, or other rock formation. They can be found in all climate types, but are most abundant in intertidal areas and semi-arid and arid deserts. Currently favored explanations controlling their formation include salt weathering, differential cementation, structural variation in permeability, and the length of the drying period between wettings. They also frequently occur in granitic rocks.
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Last weekend I was beachcombing at Moonstone Beach in Cambria, CA, when I found these cliffs with beautiful, lacy holes. Recently I heard the term for this formation but have lost it. If anyone knows what this is called, please let me know.
I've been told that it is evulsion or the work of piddock clams, but I think there's a different term for it. Anyone have any ideas?