The lower portion of the Little Colorado River flows through a meandering canyon which is about a mile wide and a half-mile deep.  The walls of this rugged gorge are a series of nearly vertical cliffs of massive limestone and sandstone separated by steep slopes or benches of shale, siltstone, or thinbedded sandstone.  The bottom can be reached near Blue Springs only by a rugged foot trail from the rim or by helicopter.  The springs originate from groundwater which moves into the area from the east and south and emerges as springflow where the canyon has penetrated the Redwall and Mauve limestones below the regional water table.  There are many spring openings along two relatively well defined reaches.