Devils Tower was formed by molten igneous rock forcing its way into the area's sedimentary rock, cooling before reaching the surface, and the sedimentary rock being eroded away.<ref>http://www.nps.gov/archive/deto/geology.htm</ref> Scientists have debated for many years exactly what process brought the molten igneous rock up. One early explanation was that it was the remains of a laccolith - a mushroom-shaped underground formation. Another theory is that Devils Tower is the remains of a volcano, though no other evidence of volcanic activity has been found in the area. | Devils Tower was formed by molten igneous rock forcing its way into the area's sedimentary rock, cooling before reaching the surface, and the sedimentary rock being eroded away.<ref>http://www.nps.gov/archive/deto/geology.htm</ref> Scientists have debated for many years exactly what process brought the molten igneous rock up. One early explanation was that it was the remains of a laccolith - a mushroom-shaped underground formation. Another theory is that Devils Tower is the remains of a volcano, though no other evidence of volcanic activity has been found in the area. |