Devils Tower National Monument

October 22, 2019



Photographer: Saundra Simmons 
Summary Authors: Saundra Simmons; Jim Foster

This impressive igneous intrusion in northeastern Wyoming stands 5,112 ft (1,558 m) above sea level. Devils Tower, the centerpiece of Devils Tower National Monument, is actually an ancient volcanic plug. As the magma in the neck of this volcano cooled, similar-sized, mostly hexagonal columns formed (bottom photo - can you find the climbers?) These columns are a phonolite porphyry, composed of rather large feldspar crystals, approximately 0.5 or 1 cm across.

Even though it’s constantly eroded by wind and rain, because it’s more resistant than the surrounding terrain, it takes on a tower-like appearance – rising some 867 ft (264 m) from its base. Called Bear Lodge by the Lakota, it’s long been a sacred landmark to Native Americans. Of note, in the movie "Close Encounters of the Third Kind," its domed top was a landing field for alien visitors. If you visit Devil Towers be sure to take the scenic trail that encircles it.