Special conditions are required, in order to preserve a footprint made in soft ground (such as an alluvial plain or a formative sedimentary deposit).

Sea levels change; sedimentary deposits also change the contours of the ancient map.

They are most common in deposits of marine environments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits.

The subsoil consists of old sedimentary deposits of schist and sandstone.

The basin floor contains thick, structurally complex sedimentary deposits that have a long geologic history of deposition, erosion, and internal deformation.