St.Nectaire - Petrified Art

This is probably the most bizarre blip I have posted for some time. We visited the Fontaines Petrifiantes in St Nectaire purely by chance and discovered this fascinating process of creating art objects using natural methods of petrifaction. I can't begin to explain how it works . The picture shows various moulds set on a "ladder" where they are covered by water laden with calcium and iron to produce the final product . If you want more info try Google !