mould when a split was lifted up. The average
rate of accumulation of the mould during the whole thirty years was
only .083 inch per year (i.e., nearly one inch in twelve years); but
the rate must have been much slower at first, and afterwards
considerably quicker.

The transformation in the appearance of this field, which had been
effected beneath my eyes, was afterwards rendered the more striking,
when I examined in Knole Park a dense forest of lofty beech-trees,
beneath which nothing grew. Here the ground was thickly strewed with
large, naked stones, and worm-castings were almost wholly absent.
Obscure lines and irregularities on the surface indicated that the
land had been cultivated some centuries ago. It is probable that a
thick wood of young beech-trees sprung up so quickly, that time enough
was not allowed for worms to cover up the stone with their castings,
before the site became unfitted for their existence. Anyhow, the
contrast between the state of the now miscalled "stony field," well
stocked with worms, and the present state of the ground beneath the
old beech-trees in Knole Park, where worms appeared to be absent, was
striking.

A narrow path running across part of my lawn was paved in 1843 with
small flag-stones, set edgeways; but worms threw up many castings, and
weeds grew thickly between them. During several years the path was
weeded and swept; but ultimately the weeds and worms prevailed, and
the gardener ceased to sweep, merely moving off the weeds, as often as
the lawn was mowed. The path soon became almost covered up, and after
several years no trace of it was left. On removing, in 1877, the thin
overlaying layer of turf, the small flag-stones, all in their proper
places, were found covered by an inch of fine mould.

Two recently published accounts of substances strewed on the surface
of pasture-land, having become buried through the action of worms, may
be here noticed. The Rev. H. C. Key had a ditch cut in a field, over
which coal-ashes had been spread, as it was believed, 18 years before,
and on the clean-cut perpendicular sides of the ditch, at a depth of
at least 7 inches, there could be seen, for a length of 60 yards, "a
distinct, very even, narrow line of coal-ashes, mixed with small coal,
perfectly parallel with the top-sward." This parallelism and the
length of the section gives interest to the case. Secondly, Mr. Dancer
states that crushed bones had been thickly strewed over a field,