OXFORDSHIRE, ENGLAND—A Neolithic earthwork consisting of three roughly concentric ditches enclosing an area of high ground overlooking the valley of the River Thame has been discovered by archaeologists from Oxford Archaeology and Cotswold Archaeology. Called a causewayed enclosure, such structures were made with short ditches and banks of earth separated by areas of undug ground, and are the earliest-known kinds of enclosures of open spaces. A small henge monument and a smaller ring-ditch were added later in the Neolithic period. This causewayed enclosure is thought to have been a place where people gathered periodically for rituals and other activities. To read about more newly discovered Neolithic sites, go to "Under Stonehenge."