pavement is intelligible.
The circumstance which has surprised me most with respect to Silchester
is that during the many centuries which have elapsed since the old
buildings were deserted, the vegetable mould has not accumulated over
them to a greater thickness than that here observed. In most places it
is only about 9 inches in thickness, but in some places 12 or even more
inches. In Fig. 11, it is given as 20 inches, but this section was drawn
by Mr. Joyce before his attention was particularly called to this
subject. The land enclosed within the old walls is described as sloping
slightly to the south; but there are parts which, according to Mr. Joyce,
are nearly level, and it appears that the mould is here generally thicker
than elsewhere. The surface slopes in other parts from west to east, and
Mr. Joyce describes one floor as covered at the western end by rubbish
and mould to a thickness of 281 2 inches, and at the eastern end by a
thickness of only 111 2 inches. A very slight slope suffices to cause
recent castings to flow downwards during heavy rain, and thus much earth
will ultimately reach the neighbouring rills and streams and be carried
away. By this means, the absence of very thick beds of mould over these
ancient ruins may, as I believe, be explained. Moreover most of the land
here has long been ploughed, and this would greatly aid the washing away
of the finer earth during rainy weather.
The nature of the beds immediately beneath the vegetable mould in some of
the sections is rather perplexing. We see, for instance, in the section
of an excavation in a grass meadow (Fig. 14), which sloped from north to
south at an angle of 3 40 , that the mould on the upper side is only six
inches and on the lower side nine inches in thickness. But this mould
lies on a mass (251 2 inches in thickness on the upper side) of dark brown
mould, as described by Mr. Joyce, thickly interspersed with small
pebbles and bits of tiles, which present a corroded or worn appearance.
The state of this dark-coloured earth is like that of a field which has
long been ploughed, for the earth thus becomes intermingled with stones
and fragments of all kinds which have been much exposed to the weather.
If during the course of many centuries this grass meadow and the other
now cultivated fields have been at times ploughed, and at other times
left as pasture, the nature of the ground in the above section is
rendered intelligible. For worms will continually have brought up fine
earth from below, which will have been stirred up by the plough whenever
the land was cultivated. But after a time a greater thickness of fine
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