present century, when the price of corn was very high, land of all kinds
seems to have been ploughed in Britain. There is, however, no reason to
doubt that in many cases the old crowns and furrows have been preserved
from a very ancient period. {269} That they should have been preserved
for very unequal lengths of time would naturally follow from the crowns,
when first thrown up, having differed much in height in different
districts, as is now the case with recently ploughed land.
In old pasture fields, the mould, wherever measurements were made, was
found to be from 1 2 to 2 inches thicker in the furrows than on the crowns;
but this would naturally follow from the finer earth having been washed
from the crowns into the furrows before the land was well clothed with
turf; and it is impossible to tell what part worms may have played in the
work. Nevertheless from what we have seen, castings would certainly tend
to flow and to be washed during heavy rain from the crowns into the
furrows. But as soon as a bed of fine earth had by any means been
accumulated in the furrows, it would be more favourable for worms than
the other parts, and a greater number of castings would be thrown up here
than elsewhere; and as the furrows on sloping land are usually directed
so as to carry off the surface water, some of the finest earth would be
washed from the castings which had been here ejected and be carried
completely away. The result would be that the furrows would be filled up
very slowly, while the crowns would be lowered perhaps still more slowly
by the flowing and rolling of the castings down their gentle inclinations
into the furrows.
Nevertheless it might be expected that old furrows, especially those on a
sloping surface, would in the course of time be filled up and disappear.
Some careful observers, however, who examined fields for me in
Gloucestershire and Staffordshire could not detect any difference in the
state of the furrows in the upper and lower parts of sloping fields,
supposed to have been long in pasture; and they came to the conclusion
that the crowns and furrows would last for an almost endless number of
centuries. On the other hand the process of obliteration seems to have
commenced in some places. Thus in a grass field in North Wales, known to
have been ploughed about 65 years ago, which sloped at an angle of 15 to
the north-east, the depth of the furrows (only 7 feet apart) was
carefully measured, and was found to be about 41 2 inches in the upper part
of the slope, and only 1 inch near the base, where they could be traced
with difficulty. On another field sloping at about the same angle to the
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