General Stratigraphy

“The clay facies of the Frenchman is quite different from the sand facies and can easily be distinguished from it in the field. The clay facies comprises greyish, greyish-green, and bluish to purplish bentonitic clays, characteristically exposed in bare, rounded, badland outcrops with a cracked "popcorn-like" surface when dry.” (Kupsch, 1956)