Anciently, the Fens were pleasant to the eye of the lover of the picturesque; for they contained shining meres and golden reed-beds, haunted by countless water-fowl, and strange, gaudy insects. "Dark-green alders," says Kingsley,[16] "and pale-green reeds stretched for miles round the broad lagoon, where the coot clanked and the bittern boomed, and the sedge-bird, not content with its own sweet song, mocked the notes of all the birds around; while high overhead hung hawk beyond hawk, buzzard beyond buzzard, kite beyond kite, as far as eye could see." What strange transformations must this wild region have undergone! There was a time, in all probability, when a great part of the German Ocean was dry land, through which, into a vast estuary between North Britain and Norway, flowed together all the rivers of North-eastern Europe--Elbe, Weser, Rhine, Scheldt, Seine, Thames, and all the rivers of east England, as far north as the Humber. Meanwhile, the valleys of the Cam, the Ouse, the Nene, the Welland, the Glen, and the Witham, were slowly "sawing themselves out" by the quiet action of rain and rivers. Then came an age when the lowland was swept away by the biting, corroding sea-wash still so powerfully destructive on the east coast of England, as far as Flamborough Head. "Wave and tide by sea, rain and river by land; these are God's mighty mills in which he makes the old world new." And as Longfellow says of moral things, so may we of physical,-- "'Though the mills of God grind slowly, yet they grind exceeding small; Though he sit and wait with patience, with exactness grinds he all.'" These ever-active causes have converted the dry land into the fens. The mud brought down by the rivers cannot get away to sea; and, with the _débris_ of the coast, is constantly swept southward by tide and current, and deposited within the great curving basin of the Wash, between Lincolnshire and Norfolk. There it is kept by the strong barrier of shifting sands coming inwards from the sea; a barrier which also confines the very water of the fens, and spreads it inland into a labyrinth of streams, shallow meres, and bogs. The rainfall, over the whole vast area of dull level, has found no adequate channels of escape for centuries; and hence we may understand how peat--the certain product of standing water--has slowly overwhelmed the rich alluvium, and swallowed up gradually the stately forests of fir and oak, ash and poplar, hazel and yew, which once spread far and wide over the blooming country. "Many a green isle needs must be In the deep wide sea of misery,"