Trundling
Trundling is the practice of rolling large rocks or boulders down hillsides. It is discouraged in many areas, for reasons of safety and environmental impact. Its practice can be traced back to rock climbers in the 18th century in North America. More specifically, "Boulder Trundling may be defined as the propulsion of fragments of the Earth's crust down mountain slopes of suitable inclination sooner than would occur from the interaction of natural forces."