Saturday, December 12, 2015
These hills are unusual because of the stripes of colorful minerals in the various levels or strata. Bentonite is an absorbent aluminium phyllosilicate clay consisting mostly of montmorillonite. The absorbent clay was given the name "bentonite" by Wilbur C. Knight in 1898, after the Cretaceous Benton Shale near Rock River, Wyoming. The different types of bentonite are each named after the respective dominant element, such as potassium (K), sodium (Na), calcium (Ca), and aluminium. See Wikipedia: Bentonite. Some of my early memories are of playing on just sort of a hill in Eastern Arizona.