Cretaceous flint from Rijckholt-St.Geertruid mine : 2D documentation Upper Cretaceous (Maastrichtian)
Jurassic flint : 3D documentation Upper Jurassic
Jurassic flint : 2D documentation Upper Jurassic
Cretaceous flint from Rijckholt-St.Geertruid mine : 3D documentation Upper Cretaceous (Maastrichtian)