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 4IST0RY OF SUSSEX EAR A fortresses partly inaccesible, by reason of precipices, cliffs, or water, additionally defended, by artificial works, usually known as promontory fortresses R fortresses on hill-tops nith artificial defences, following the natural line of the hill; Or though usually on high ground, less ' dependent, on natural slopes for protection C Rectangular or other simple enclosures, int forts end towns, of the fiomano -British per D forts consisting only of a mount with encircling ditch or fosse