Griffes du diable (devil's claws)

A number of churches around here have rather strange markings or scratches on the stone posts next to the door, in popular speech called devil's claws or pierres sauvages (barbaric stones).
One of the romantic explanations for those scratches is, that when the devil wanted to enter the church, but was stopped by a higher power, he got so angry that he scratched the stones next to the door he could not enter.
The real origin is obscure; it was possibly a place where artisans or farmers sharpened their tools, hence public grindstones, or these are marks left behind by believers who ate the grated dust or mixed it in elixirs to cure skin diseases.
So far I have found these decorations on the churches of Ougy, Granges, Saint-Clément-sur-Guye, Saint-Maurice-des-Champs and Chamilly (photo).
This entry is not to be found in Mr. Eduard van Boxtel's glossary (letter G), however, I thought it was too nice to skip it.
See also pierre sauvage (synonym).

Saint-Pierre et Saint-Paul - Chamilly