 Devil's Tower, landmark of the Black Hills, source of legends, and the geological record of part of the history of this planet. Long before man walked the earth, the last dinosaurs wandered here in what was then probably lush forest swampland, but the climate was gradually cooling and deep within the earth changes were taking place that would dramatically alter the shape of the land. Before this upheaval came the Rocky Mountains, the Black Hills, and the uplifting of the western plains. Some of the stresses were volcanic, and in places they broke through the weakened spots in the earth's crust and their lava flowed to the surface. Devil's Tower, like little Missouri buttes four miles to the northwest, is a core of one of these ancient extinct volcanoes. The fiery liquid magma rose through the softer sedimentary rock, barely disturbing its layers. As the rock cooled, it contracted, and the contraction caused cracks to form, radiating from many points and lengthening until they met other cracks. As the cooling continued, the cracks went deeper and deeper into the rock, creating a mass of four, five, and six-sided columns. Although magma volcano reached the surface, that portion of the tower existing today was still underground, hidden by the layers of sedimentary rock. Above it flowed the ancestor of the Belfouche River that would be largely responsible for revealing Devil's Tower as we know it. For millions of years, the river, along with wind, rain, and the effects of freezing and thawing, slowly wore away the soft sedimentary rock. The much harder igneous rock remained, eventually rising higher and higher above the surrounding land. You can see that the upper third of the tower is more worn than the rest. That's because when that portion had been exposed, the river began to flow over a sedimentary layer that was harder and more resistant to erosion. Although the upper part of the tower was battered longer by the elements, while the lower part was still buried underground. After the river wore through the more resistant layer of sediment, the rest of the tower was exposed fairly quickly. The top third may also have evidenced some of the block-jointing seen in the bottom third. The tower still rises through sedimentary rock, but those layers are now covered with callus, fragments from the tower itself that protect the softer surrounding base from further erosion. Over the years, the effects of cold and heat made the rock contract and expand. When parts of the columns were weakened by this process, gravity did the rest. And the fallen rock accumulated around the base. Most of it seems to have come from the upper part. Depends of columns that range from a few inches in diameter to enormous chunks 14 feet across and 25 feet long. The lichen growing on the callus indicates there have been no large rock falls in the last few hundred years. It was only a little over a hundred years ago that Devil's Tower got its present name when a U.S. Geological Survey Party saw it during an expedition into the Black Hills in 1875. The Indians had called it Mateo Tipi, which means Bear Lodge, but the survey team misunderstood the name and called it Bad God's Tower, later shortened to Devil's Tower. In 1906, Congress passed the Antiquities Act, allowing the president to preserve historic or scientific landmarks on government land. That same year, President Theodore Roosevelt proclaimed Devil's Tower the first national monument in the country. For eons, it has stood sentinel over these grasslands and forests. Campers, hikers, and climbers come to enjoy the peace and recreation they find in its shadow, surrounded by a wealth of trees, flowers, and wildlife. Impressive in its beauty and its permanence, Devil's Tower is, most of all, a remarkable natural record of geological history. A witness to its own epic story.