[The country] consists of a sort of plateau or tableland about 200 feet above sea-level, and deeply indented with numerous deep chasms and narrow ravines, the bed of whose creek is, to all intents and purposes, on the same level as the sea... Mr Carver, previous to my arrival, attempted to overcome the difficulty by heading up all the creeks, and he ran a trial line upwards of eight miles (13 km) in length, but this brought him to the summit of the range from which there was no getting down.