The Fens
The Fens are very low-lying compared with the chalk and limestone uplands that surround them – in most places no more than 10 m above sea level. Indeed, as a result of drainage and the subsequent shrinkage of the peat fens, many parts of the Fens now lie below the average sea level. Although one writer in the seventeenth century described the Fenland as all lying above sea level (in contrast to the Netherlands),<ref>H. C. A discourse concerning the drayning of fennes and surrounded grounds in the sixe counteys of Norfolk, Suffolke, Cambridge, with the Isle of Ely, Huntington, Northampton and Lincolne. London: 1629.