and
"some years afterwards" these were found "several inches below the
surface, at a uniform depth." Worms appear to act in the same manner
in New Zealand as in Europe; for Professor J. von Haast has described
a section near the coast, consisting of mica-schist, "covered by 5 or
6 feet of loess, above which about 12 inches of vegetable soil had
accumulated." Between the loess and the mould there was a layer from 3
to 6 inches in thickness, consisting of "cores, implements, flakes,
and chips, all manufactured from hard basaltic rock." It is,
therefore, probable, that the aborigines, at some former period, had
left these objects on the surface, and that they had afterwards been
slowly covered up by the castings of worms.

Farmers in England are well aware that objects of all kinds, left on
the surface of pasture-lands, after a time disappear, or, as they say,
work themselves downwards. How powdered lime, cinders, and heavy
stones, can work down, and at the same rate, through the matted roots
of a grass-covered surface, is a question which has probably never
occurred to them.

_The sinking of great stones through the action of worms._--When a
stone of large size and of irregular shape is left on the surface of
the ground, it rests, of course, on the more protuberant parts; but
worms soon fill up with their castings all the hollow spaces on the
lower side; for, as Hensen remarks, they like the shelter of stones.
As soon as the hollows are filled up, the worms eject the earth which
they have swallowed beyond the circumference of the stones; and thus
the surface of the ground is raised all round the stone. As the
burrows excavated directly beneath the stone after a time collapse,
the stone sinks a little. Hence it is, that boulders which at some
ancient period have rolled down from a rocky mountain or cliff on to a
meadow at its base, are always somewhat imbedded in the soil; and,
when removed, leave an exact impression of their lower surfaces in
the under-lying fine mould. If, however, a boulder is of such huge
dimensions, that the earth beneath is kept dry, such earth will not be
inhabited by worms, and the boulder will not sink into the ground.

A lime-kiln formerly stood in a grass-field near Leith Hill Place, in
Surrey, and was pulled down 35 years before my visit; all the loose
rubbish had been carted away, excepting three large stones of
quartzose sandstone, which it was thought might hereafter be of some
use. An o