floor would have been scored by the ploughshare, the tesser torn up, and
the tops of the old walls knocked down.
When the concrete and tesser were first cleared over a space of 14 by 9
ft., the floor which was coated with trodden-down earth exhibited no
signs of having been penetrated by worms; and although the overlying fine
mould closely resembled that which in many places has certainly been
accumulated by worms, yet it seemed hardly possible that this mould could
have been brought up by worms from beneath the apparently sound floor.
It seemed also extremely improbable that the thick walls, surrounding the
room and still united to the concrete, had been undermined by worms, and
had thus been caused to sink, being afterwards covered up by their
castings. I therefore at first concluded that all the fine mould above
the ruins had been washed down from the upper parts of the field; but we
shall soon see that this conclusion was certainly erroneous, though much
fine earth is known to be washed down from the upper part of the field in
its present ploughed state during heavy rains.
Although the concrete floor did not at first appear to have been anywhere
penetrated by worms, yet by the next morning little cakes of the
trodden-down earth had been lifted up by worms over the mouths of seven
burrows, which passed through the softer parts of the naked concrete, or
between the interstices of the tesser . On the third morning twenty-five
burrows were counted; and by suddenly lifting up the little cakes of
earth, four worms were seen in the act of quickly retreating. Two
castings were thrown up during the third night on the floor, and these
were of large size. The season was not favourable for the full activity
of worms, and the weather had lately been hot and dry, so that most of
the worms now lived at a considerable depth. In digging the two trenches
many open burrows and some worms were encountered at between 30 and 40
inches beneath the surface; but at a greater depth they became rare. One
worm, however, was cut through at 481 2, and another at 511 2 inches beneath
the surface. A fresh humus-lined burrow was also met with at a depth of
57 and another at 651 2 inches. At greater depths than this, neither
burrows nor worms were seen.
As I wished to learn how many worms lived beneath the floor of the
atrium a space of about 14 by 9 feet Mr. Farrer was so kind as to make
observations for me, during the next seven weeks, by which time the worms
in the surrounding country were in full activity, and were working near
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