Mule Ears is a pair of plugs. A plug occurs when a volcano goes extinct, the lava no longer flows. It cools and remains in the form of the neck of the volcano. Years, eons and centuries go by and the mountain is eroded. The plug material is much harder, and remains. This double plug, looking like ears, is one of the landmarks of wild formations south of the Chisos Mountains.
The Santa Elena canyon was created by the Rio Grand slicing a chanel through the slowly rising rock layers, which formed today's Mesa Aguila. This high Mesa dominates the southern sky line in the Western part of the Park. > Santa Elena is the first canyon you experience in on a float trip into Big Bend. It is the most brilliant of the three, but not by much. The long passage ways usually takes two days to navigate by raft. A big thrill at the beginning is a section called the Rock Slide, where huge boulders have been washed or fallen to provide a cateract with chutes the river chanels through. If the river is high, it is quite a thrill. If it is too high, the danger is too great for passage. It is always different and requires scouting the best chute to take.
