Note 124 — Chapter VIII

The Fleam Dyke is one of the great prehistoric lines of defence which were run from the Fens of the Cam to the summit of the East Anglian heights. Those heights were in ancient times clothed with dense forest, and formed an impenetrable barrier against enemies from the west seeking to invade the East Anglian districts. So too did the morasses of the fenland. But between fen and forest stretched a strip of open grassland furnishing easy access. To defend this, the only gate into their territory, was the great object of the inhabitants of those districts; and they ran across it two stupendous earthworks, the Fleam Dyke as their outer bulwark and the Devil's Dyke, which we meet at Newmarket, as the inner.[124] The former stretches for a length of some ten miles from the banks of the Cam at Fen Ditton to the uplands by Balsham (its course broken by Fulbourn Fen); the latter ranges in a long unbroken rampart from the Fen at Reach to Wood Ditton (i.e. "the ditch-end in the forest").