Non-portable evidence of past human behavior, activity, and technology, found on or in the ground. Prehistoric features commonly include fire pits and hearths, burned earth and clay, trash and garbage pits, postholes, evidence of house floors or basins, storage pits, clusters of artifacts (e.g., chipped and broken stones, caches of projectile points, ceramics or pottery sherds), human and animal burials, clusters of animal bone, and earthworks (such as mounds and circular enclosures), petroglyphs and pictographs (respectively symbols carved or pecked into stone and painting or drawings on stone) , and middens (cultural refuse buildup). Historic features include evidence of fires and fire pits, ash and charcoal lenses and stains, trash and garbage pits and dumps, middens, postholes, house foundations and other structural remains (e.g., wells, cisterns, fence lines, ditches, canals, landscapes, embankments, mill races, dams, old trails and roads), cemeteries, human burials, and clusters of historic artifacts.