sentences:  The abbey was apparently enclosed on the land side by a fosse or trench or canal which left it surrounded on all sides by water and therefore, relatively secure from attack of an enemy.Premonstratensian canons regular from Alnwick Abbey in Northumberland had founded Dryburgh Abbey, on the banks of the River Tweed on Martinmas 1150.The site of Soulseat Abbey (now a mound with five 16th-century gravestones thereon) is on the promontory of a loch with a very narrow isthmus, thus perhaps fitting the description.