Littlestone wrote:
The natural way is for a large piece of grit or small stone to get caught in a depression then when wind swirls it around creating a bowl like appearance.
Ahh, that makes sense.
These remind me of shellfish fossils though!
Dunno, need to go back and have another ganders.
One of the most common natural examples of "cups " are due to solution holes where the "cement " holding the rock together has a weakness and subsequent exposure to rain ,chemical weathering and freeze thaw produces what looks like something that isman made . I think that may well be the case on the pics .
