The Late Mississippian-Early Pennsylvanian Surprise Canyon Formation is a conglomerate, sandstone, limestone and dark purple siltstone type formation, occurring as 'channel fill'. The Surprise Canyon Formation was deposited upon a mostly horizontal, much eroded Redwall Limestone surface, the Redwall originally deposited as marine-(oceanic) limestone, (400 to 700 ft thick); when the Surprise Canyon Formation was being deposited, the Redwall Limestone surface existed under karst topography conditions, in a "warm, and humid" (paleo)-environment. The karst topography created "sinks, caves, and underground channels", and created "deep ravines and stream valleys developed as caverns collapsed". Some valleys probably filled with " 'clayey red-orange soil' similar to that known in the Tropics toda