Two methods, working side by side, have from the beginning of human habitation reclaimed the Fens. The first has been the canalisation, the fencing in of the tideways; the second has been the banking out of the general sea. The spring tides covered much of this land, and when they retired left it drowned. Against their universal advancing sheet of water a bank could be made. Such a bank cut off the invasion of the hundreds of runnels, small and great, by which the more ordinary tides that could not cover the surface had yet crept into the soil and soaked it through.
When such a bank had been built, gates, as it were, permitted the water to spend its force and also to use its ebb and flow for the draining of the land beyond. The gates which let the tide pour up and down the main ways became the new mouths of the main rivers; inland the courses of the rivers (which now took all the sea and thus became prodigious) were carefully guarded. Even before trenches were dug to drain the fields around, earth was thrown up on either side of the rivers to confine them each to one permanent channel; nor did the level of the rivers rise, or their beds gets clogged; the strength of the tide sufficed for the deepening of their channels. Into the rivers so fortified the other waterways of the Fens were conducted.
By these methods alone much of the land was rendered habitable and subject to the plough. Probably these methods were enough to make it all it was in the Middle Ages. It was only far later, almost in our own time, that water was gathered by trenches in the lowland beneath the rivers and pumped out artificially with mills; nor is it quite certain even now that this method (borrowed from Holland) is the best; for the land, as I have said, is above and not below the sea.
Of these words, whose tradition is immemorial, the greatest, of course, are the sea-walls.
Perhaps the river-walls came first, but the great bank which limited and protected the land against the sea is also older than any history.
It is called Roman, and relics of Rome have been found in it, but it has not the characteristic of Roman work. It runs upon no regular lines; its contour is curved and variable. It is surely far older than the Roman occupation. Earth, heaped and beaten hard, is the most enduring of things; the tumuli all over England have outlasted even the monoliths, and the great defensive mounds at Norwich and at Oxford are stronger and clearer cut than anything that the Middle Ages have left. This bank, which first made Fenland, still stands most conspicuous. You may follow it from the Nene above Sutton Bridge right over to Lynn River, and again northward from Sutton Bridge (or rather, from the ferry above it) right round outside Long Sutton and Holbeach, and by Forsdyke Bridge and outside Swyneshead; everywhere it encloses and protects the old parishes, and everywhere seaward of it the names of the fields mark the newest of endeavours.
We returned from a long wandering upon the desolate edges of the sea to the bank which we proposed to follow right round to the mouth of the Ouse: a bank that runs not straight, but in great broken lines, as in old-fashioned fortification, and from which far off upon the right one sees the famous churches of the Wringland, far off upon the left a hint beyond the marshes and the sands of the very distant open sea.
A gale had risen with the morning, and while it invigorated the travellers in these wastes it seemed to increase their loneliness, for it broke upon nothing, and it removed the interest of the eye from the monotonous sad land to the charge and change of the torn sky above, but in a sense also it impelled us, as though we were sailing before it as it swept along the edge of the bank and helped us to forget the interminable hours.
The birds for whom this estuary is a kind of sanctuary and a place of secure food in all weathers, the birds swept out in great flocks over the flats towards the sea. They were the only companionship afforded to us upon this long day, and they had, or I fancied they had, in their demeanour a kind of contempt for the rare human beings they might see, as though knowing how little man could do upon those sands. They fed all together upon the edge of the water, upon the edge of the falling tide, very far off, making long bands of white that mixed with the tiny breaking wavelets. Now and then they rose in bodies, and so rising disappeared; but as they would turn and wheel against the wind, seeking some other ground, they sent from moment to moment flashes of delicate and rare light from the great multitude of their wings. I know of nothing to which one may compare these glimpses of evanescent shining but these two things—the flash of a sword edge and the rapid turning in human hands of a diaphanous veil held in the light. It shone or glinted for a moment, then they would all wheel together and it disappeared.