What is notably found at the base of a cliff as evidence of gravity erosion?

The presence of angular, unsorted rocks at the base of a cliff serves as strong evidence of gravity erosion. This phenomenon occurs when rock fragments break off from a cliff face due to gravity and fall to the ground. As these fragments descend, they typically accumulate at the base of the cliff, where they remain unreworked by any sorting processes that would be characteristic of other erosion types, such as water or wind. The angular shape of the rocks indicates that they have not traveled far from their source, which further supports the idea of gravity being the primary force at play.

In contrast, features such as smooth pebbles often indicate extensive transportation by water, where rounding occurs due to abrasion. Sorted sands suggest that the material has been moved and deposited by winds or water, resulting in a more uniform particle size and shape. Silty soil, while it can be found near cliffs, is often the product of finer particles transported by water and does not directly showcase the immediate effects of gravity erosion. Therefore, the angular, unsorted rocks are the most distinct evidence of the mechanical action of gravity in the erosion process.