▁the ▁North ▁Down s , ▁this ▁consists ▁of ▁ch alk ▁sur mount ed ▁by ▁the ▁Black he ath ▁B eds ▁of ▁sand ▁and ▁gra vel . ▁ ▁As ▁a ▁human ▁settlement , ▁Ro chester ▁became ▁established ▁as ▁the ▁lowest ▁river ▁crossing ▁of ▁the ▁River ▁Med way , ▁well ▁before ▁the ▁arrival ▁of ▁the ▁Rom ans . ▁ ▁It ▁is ▁a ▁foc al ▁point ▁between ▁two ▁routes , ▁being ▁part ▁of ▁the ▁main ▁route ▁connecting ▁London ▁with ▁the ▁Cont inent ▁and ▁the ▁north - s outh ▁routes ▁following ▁the ▁course ▁of ▁the ▁Med way ▁connecting ▁Ma id stone ▁and ▁the ▁We ald ▁of ▁Kent ▁with ▁the ▁Th ames ▁and ▁the ▁North ▁Sea . ▁The ▁Th ames ▁Marsh es ▁were ▁an ▁important ▁source ▁of ▁salt . ▁Ro chester ' s ▁roads ▁follow ▁north ▁Kent ' s ▁valle ys ▁and ▁rid ges ▁of ▁ste ep - s ided ▁ch alk ▁b ourn es . ▁There ▁are ▁four ▁ways ▁out ▁of ▁town ▁to ▁the ▁south : ▁up ▁Star ▁Hill , ▁via ▁The ▁Del ce , ▁along ▁the ▁Ma id stone ▁Road ▁or ▁through ▁Bor stal . ▁The ▁town ▁is ▁in ext ric ably ▁linked ▁with ▁the ▁neighbour ing ▁Med way ▁Town s ▁but ▁separated ▁from ▁Ma id stone ▁by ▁a ▁protect ive ▁r idge ▁known ▁as ▁the ▁Down s , ▁a ▁designated ▁area ▁of ▁Out standing ▁Natural ▁Beaut y . ▁ ▁At ▁its ▁most ▁limited ▁ge ographical ▁size , ▁Ro chester ▁is ▁defined ▁as ▁the ▁market ▁town ▁within ▁the ▁city ▁walls , ▁now ▁associated ▁with ▁the ▁historic