part of the stone kerb and four capstones covering a coffin-shaped chamber. The mound contains a kerb of large stones, measuring 8.3m by 8m. The burial chamber is oriented east-west, with the entrance facing east. The chamber interior measures 7m by almost 1.5m wide across the middle, with a boat or coffin-shaped layout, the sides curving in slightly to 1m wide at the western end and 0.65m wide at the entrance. The entrance is partially blocked. The chamber walls are lined with stone slabs. Four capstones make up the chamber roof. The chamber of this entrance grave is considered to be an excellent example of a coffin or boat-shaped chamber. One of the entrance graves on Porth Hellick Down has a burial chamber that is constructed along a massive rock outcrop. The rock is integrated into the grave's structure. The burial chamber consists of a circular mound of stacked rubble, 13m in diameter and 1m high. The southern end of the chamber is lined with large slabs on its west side and a large boulder on the east side. Another large slab sits on the slab walls and provides a roof for the chamber. This grave has survived mostly intact, retaining its original form and layout. It has lost one of its capstones. The incorporation of natural rock outcropping into the grave's structure is an unusual feature of a Scillonian entrance grave. Porth Hellick Down is the site of a prehistoric linear boundary which traverses its eastern slope. The linear boundary progresses as a nearly straight line of small upright stones, up to 0.5m high and 1.5m to 6m apart. Beginning at the eastern edge of the Down, the linear boundary stretches southeast to northwest for 17m, and then continues for another 23m. The boundary measures up to 1m wide, 0.1 m high and is mainly covered by heather turf. Not typically found in prehistoric Britain, The Isles of Scilly is the setting for a number of linear boundaries that are directly associated with groupings of prehistoric burial monuments. See also Bant's Carn Innisidgen Obadiah's Barrow Gallery References External links Porth Hellick walking tour - Isles of Scilly Wildlife Trust Innisidgen walking tour — Isles of Scilly Wildlife Trust Bronze Age sites in Cornwall Archaeological sites in Cornwall Geography of Cornwall History of the Isles of Scilly Prehistoric sites in Cornwall English Heritage sites in the Isles of Scilly St