The Changing Faces of Pompeys Pillar

The Changing Faces of Pompeys Pillar. Stabilizing the Rock. Pompeys Pillar is a unique geological formation born of water. Sediments carried by an ancient river were very slowly and forcefully compacted into rock-the same sandstone and siltstone visible today in the Pillar. As the waters receded and sediment eroded, this pillar of rock was left standing alone and isolated on the south side of the Yellowstone River. Wind, rain, freezing and thawing are natural processes that have been reshaping the Pillar for thousands of years. , Today, the process of erosion has accelerated swiftly, and now requires stabilization of portions of the rock, including the area containing William Clark's signature. To ensure that Pompeys Pillar survives for future generations to enjoy, geotechnical engineers will assess and make recommendations, after which work will begin on shoring up "the stone bones" of Pompeys Pillar. Unfortunately during this time, we will be unable of offer access to the boardwalk on the Pillar. , However, just because we cannot climb the rock does not mean we cannot experience the same natural wonder that captivated William Clark and has attracted human activity for millennia. Walk around the base of the Pillar to explore this "remarkable rock" from the point of view of Clark's arrival. Keep you eyes and ears open for the wildlife that call Pompeys Pillar home, walk along the Yellowstone River, and hike our nature trails for a change of scenery.