What is evidence of gravity erosion?

Gravity erosion is a geological process that involves the movement of rock and soil down a slope due to the force of gravity. The presence of unsorted and angular rocks at the base of a cliff serves as strong evidence of this process. When materials like rocks and debris fall or tumble down a steep slope, they typically do not have the chance to become rounded or sorted by size, as they would in water or wind transport situations. Instead, they often remain angular due to the lack of prolonged weathering and abrasion that would occur in those environments.

In contrast, sorted and rounded rocks typically indicate a different type of erosion, such as water or wind transport, where continuous movement leads to the smoothing and sorting of materials. Layered sediments in a flat area are indicative of deposition rather than erosion, showing how materials settle out of a transporting medium. Fossils embedded in soil relate more to the biological processes and sedimentary deposition rather than directly to gravity erosion. Thus, the unsorted and angular rocks provide clear, direct evidence that gravity is actively at work in shaping the landscape.