Pont Farin

Pont Farin is the small village in Cantal where, in 1905, Bernard Brunhes discovered the inversions in the Earth's magnetic field. A layer of clay that had been baked by a lava flow had fossilized the magnetic field of that time.

The layer of baked clay at Pont Farin, with the lava flow above. (Credit: Laurent Sacco/Futura-Sciences).