An east and west section, 30 ft.in length, was made across a room inthe Basilica, now called the Hall of the Merchants (Fig.9).The hard concrete floor, still covered here and there with tesserae, was found at 3 ft.beneath the surface of the field, which was here level.On the floor there were two large piles of charred wood, one alone of which is shown in the part of the section here given.This pile was covered by a thin white layer of decayed stucco or plaster, above which was a mass, presenting a singularly disturbed appearance, of broken tiles, mortar, rubbish and fine gravel, together 27 inches in thickness.Mr.Joyce believes that the gravel was used in making the mortar or concrete, which has since decayed, some of the lime probably having been dissolved.The disturbed state of the rubbish may have been due to its having been searched for building stones.This bed was capped by fine vegetable mould, 9 inches in thickness.From these facts we may conclude that the Hall was burnt down, and that much rubbish fell on the floor, through and from which the worms slowly brought up the mould, now forming the surface of the level field.
A section across the middle of another hall in the Basilica, 32 feet 6 inches in length, called the AErarium, is shown in Fig.10.It appears that we have here evidence of two fires, separated by an interval of time, during which the 6 inches of "mortar and concrete with broken tiles" was accumulated.Beneath one of the layers of charred wood, a valuable relic, a bronze eagle, was found; and this shows that the soldiers must have deserted the place in a panic.Owing to the death of Mr.Joyce, I have not been able to ascertain beneath which of the two layers the eagle was found.The bed of rubble overlying the undisturbed gravel originally formed, as I suppose, the floor, for it stands on a level with that of a corridor, outside the walls of the Hall; but the corridor is not shown in the section as here given.The vegetable mould was 16 inches thick in the thickest part; and the depth from the surface of the field, clothed with herbage, to the undisturbed gravel, was 40 inches.
The section shown in Fig.11 represents an excavation made in the middle of the town, and is here introduced because the bed of "rich mould" attained, according to Mr.Joyce, the unusual thickness of 20 inches.Gravel lay at the depth of 48 inches from the surface; but it was not ascertained whether this was in its natural state, or had been broughthere and had been rammed down, as occurs in some other places.
The section shown in Fig.12 was taken in the centre of the Basilica, and though it was 5 feet in depth, the natural sub-soil was not reached.The bed marked "concrete" was probably at one time a floor; and the beds beneath seem to be the remnants of more ancient buildings.The vegetable mould was here only 9 inches thick.In some other sections, not copied, we likewise have evidence of buildings having been erected over the ruins of older ones.In one case there was a layer of yellow clay of very unequal thickness between two beds of debris, the lower one of which rested on a floor with tesserae.The ancient broken walls appear to have been sometimes roughly cut down to a uniform level, so as to serve as the foundations for a temporary building; and Mr.Joyce suspects that some of these buildings were wattled sheds, plastered with clay, which would account for the above-mentioned layer of clay.
Turning now to the points which more immediately concern us.Worm- castings were observed on the floors of several of the rooms, in one of which the tesselation was unusually perfect.The tesserae here consisted of little cubes of hard sandstone of about 1 inch, several of which were loose or projected slightly above the general level.One or occasionally two open worm-burrows were found beneath all the loose tesserae.Worms have also penetrated the old walls of these ruins.A wall, which had just been exposed to view during the excavations then in progress, was examined; it was built of large flints, and was 18 inches in thickness.It appeared sound, but when the soil was removed from beneath, the mortar in the lower part was found to be so much decayed that the flints fell apart from their own weight.Here, in the middle of the wall, at a depth of 29 inches beneath the old floor and of 49.5 inches beneath the surface of the field, a living worm was found, and the mortar was penetrated by several burrows.