| View of the highlands of the Pinnacles Badlands. The cliffs and buttes at the top of the canyon are the Sharps formation, whereas the lower cliff slopes are the Brule Formation. Some of the narrow ridges in the Pinnacles area follow resistant rock preserved is clastic dikes in the vicinity. Clastic dikes are vertical fractures (possibly deep dessication fissures) that filled with sediment as the fractures formed as the White River Beds dried out over time. The fractures are also possibly related to the tectonic activity related to the Sage Creek Anticline that partly underlies the High Pinnacles area. |
