The deposits here clearly suggest that the region was covered by an inland sea when deposited in the Permian.  The sedimentary rocks are part of the Castile Formation which consists of bands of dark brown calcite that continuously alternate with lighter anhydrite in layers or fine laninae called varves.  Each varve represents two layers deposited during the course of a year.  During slightly wetter conditions of the year fresh water was added to the sea causing the calcite to be deposited while in drying periods of the year evaporation led to anhydrite deposition.   Bands of small folds called microfolds can be found within the Castile Formation believed to be due to ripple marks or slumping.