piles where there had been weirs.

Sometimes, after great rains, these piles swept away the timbers of the
weir, driven by the irresistible power of the water, and then in its
course the flood, carrying the balks before it like battering rams,
cracked and split the bridges of solid stone which the ancients had
built. These and the iron bridges likewise were overthrown, and
presently quite disappeared, for the very foundations were covered with
the sand and gravel silted up.

Thus, too, the sites of many villages and towns that anciently existed
along the rivers, or on the lower lands adjoining, were concealed by the
water and the mud it brought with it. The sedges and reeds that arose
completed the work and left nothing visible, so that the mighty
buildings of olden days were by these means utterly buried. And, as has
been proved by those who have dug for treasures, in our time the very
foundations are deep beneath the earth, and not to be got at for the
water that oozes into the shafts that they have tried to sink through
the sand and mud banks.

From an elevation, therefore, there was nothing visible but endless
forest and marsh. On the level ground and plains the view was limited to
a short distance, because of the thickets and the saplings which had now
become young trees. The downs only were still partially open, yet it was
not convenient to walk upon them except in the tracks of animals,
because of the long grass which, being no more regularly grazed upon by
sheep, as was once the case, grew thick and tangled. Furze, too, and
heath covered the slopes, and in places vast quantities of fern. There
had always been copses of fir and beech and nut-tree covers, and these
increased and spread, while bramble, briar, and hawthorn extended around