Environmental change results in an interbedded sequence of sediments, soils and erosional contacts .
Stratigraphy essential to archaeological interpretation . The archaeological or ecological contents of the sediments or its age are not considered in the definition of the lithostratigraphic unit. Waters uses Figure 2.24 as an example - riverine alluvium 8. Deposition interrupted by a. short intervals of stability b. long intervals of stability pedogenesis c. intervals of erosion 9. Conformable contacts - surfaces between lithostratigraphic units that represent no significant breaks in deposition.