Causewayed enclosures are often located on hilltop sites, encircled by one to four concentric ditches with an internal bank. Enclosures located in lowland areas are generally larger than hilltop ones. Crossing the ditches at intervals are causeways which give the monuments their names. It appears that the ditches were excavated in sections, leaving the wide causeways intact in between. They should not be confused with segmented, or causewayed ring ditches, which are smaller and are thought to relate only to funerary activity, or with hillforts, which appeared later and had a definite defensive function. With regard to defensive functionality, however, evidence of timber palisades has been found at some sites such as Hambledon Hill.