Sedimentary structure is the spatial distribution and arrangement of the components of sedimentary rocks. It is the structure that forms through physical, chemical and biological effects during or after deposition. Primary sedimentary structures, such as bedding and ripple marks, are controlled by the sedimentation conditions and form during or prior to sedimentation. Structures such as sutures that are formed by compaction or lithification during or after sedimentation are called secondary sedimentary structures. Primary sedimentary structures are good indicators of the force and flow of the sedimentary medium and can be used to assess the depositional environment and the proper sequence of rock strata.