along boundary lines which show the subdivision of the Quarantine ground at that time for hospital, recreation and military purposes; a double chain wire three feet [one metre] high fence at the entry gate to the place which served as a "neutral zone" across which internees could talk with visitors; wooden paling fences around the staff cottages; chain wire fences around the Isolation and Hospital precincts which separated them from healthy areas; foreshore stone and concrete walls at the Quarantine Beach wharf; low sandstone block kerbing and retaining walls on the main access roads; and section of remnant paling fences in bush around the Hospital area. The sandstone block walls are generally in fair-to-good condition. Some sections, however, have collapsed due to water erosion undermining their footings. Further sections are in imminent danger of collapse. Blocks in the wall end near The Old Mans Hat have seriously eroded due to wind and salty sea spray. Wire fences are substantially intact, though are prone to rusting. Existing timber fences around staff cottages are of recent construction [1985-90], mostly in good condition, though prone to distortion due to high winds. The stone walls and site fencing generally are important legacies of quarantine isolation practices. Obelisk A prominent sandstone obelisk stands on the south-eastern edge of the Station. An obelisk is shown at this location on site plans dating from 1807 to 1809, though it is not known if the existing one is the original. The memorial is in fair condition but requires some stonework repairs at the base. It may prove to be highly significant, if it is the original, as the oldest surviving structure on North Head and one of the oldest on Sydney Harbour. The obelisk is one of the few landscape elements relating to a non-quarantine function, though as navigation markers they relate to the overall maritime themes that include quarantine. Roads and paths Roads and paths throughout the place include the bitumen roads, sandstone-paved roads and pedestrian paths to The Old Mans Hat area and between the wharf and hospital areas. There is a hierarchy of paths and roads, ranging from sealed vehicle roads, through sealed footpaths and ramps, to unsealed tracks, especially into the surrounding bushland. These reflect how the landscape was lived in, and the strong separation of the managed landscape of the Station precincts and the informality of the surrounding areas such as The Old