▁town , ▁compr ising ▁the ▁old ▁par ishes ▁of ▁St . ▁Mary , ▁St . ▁Martin ▁and ▁St . ▁Thomas , ▁lies ▁on ▁the ▁right ▁( west ) ▁bank ▁of ▁the ▁river . ▁On ▁the ▁left ▁bank ▁are ▁the ▁sub ur bs ▁of ▁Pr ender g ast ▁and ▁Cart lett . ▁At ▁this ▁point , ▁a ▁pair ▁of ▁sand stone ▁rid ges ▁extending ▁east - west ▁and ▁separated ▁by ▁a ▁deep , ▁narrow ▁valley , ▁are ▁cut ▁through ▁by ▁the ▁Western ▁C led d au . ▁This ▁leaves ▁two ▁high ▁sp urs ▁on ▁the ▁west ▁side ▁of ▁the ▁river . ▁On ▁the ▁northern ▁sp ur , ▁the ▁castle ▁and ▁its ▁surrounding ▁settlement ▁form ▁the ▁core ▁of ▁St ▁Martin ' s ▁parish . ▁ ▁On ▁the ▁southern ▁sp ur , ▁the ▁High ▁Street ▁asc ends ▁ste ep ly ▁from ▁the ▁river ▁and ▁forms ▁the ▁core ▁of ▁St ▁Mary ' s ▁parish . ▁From ▁the ▁foot ▁of ▁each ▁sp ur , ▁ancient ▁brid ges ▁cross ▁the ▁river ▁to ▁Pr ender g ast : ▁St ▁Martin ' s ▁Bridge ▁(" the ▁Old ▁Bridge ") ▁and ▁St ▁Mary ' s ▁Bridge ▁(" the ▁New ▁Bridge ", ▁built ▁in ▁ 1 8 3 5 ). ▁St ▁Thomas ' s ▁parish ▁occup ies ▁the ▁south ▁side ▁of ▁the ▁southern ▁sp ur . ▁From ▁these ▁core ▁areas , ▁the ▁town ▁has ▁spread , ▁mainly ▁along ▁the ▁rid ges . ▁In ▁addition ▁to ▁the ▁four ▁ancient ▁parish ▁churches , ▁the ▁remains ▁of ▁an ▁August in ian ▁pri ory ▁are ▁visible ▁at