Devils Tower
44.590603°N 104.719961°W

July, 2003

Devil's Tower
44.592259°N 104.720451°W

In 1906, Devils Tower was established by President Theodore Roosevelt as the first national monument in the United States.

Wikipedia claims that the origin of Devils Tower is still debated, but this is clearly not true. Devils Tower is the neck of an ancient volcano. The igneous rock (geologists call it a phonolite porphyry) is 40 million years old and formed inside the throat of a volcano (as magma moves to the surface through the neck of the volcano from the magma chamber below it can cool in place before erupting on the surface). Devils Tower has distinctive columns geologists refer to as columnar jointing which forms from the cooling of magma near the surface. As the volcano began to erode, the neck was harder than the surrounding volcanic and sedimentary rocks. The neck (Devils Tower) is all that is left of the ancient volcano.

Devils Tower

Devils Tower (Lakota: Matȟó Thípila or Ptehé Ǧí, which means “Bear Lodge” and ”brown buffalo horn”, respectively) (Arapaho: Wox Niiinon ) is an igneous intrusion or laccolith located in the Black Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River. It rises dramatically 1,267 feet (386 m) above the surrounding terrain and the summit is 5,114 feet (1,559 m) above sea level.

• http://en.wikipedia.org/wiki/Devils Tower
• Hillman 1000 Wonders
• Press, F. and Siever, R., 1986, Earth, W. H. Freeman and Co., 649 p.