Page:The Formation of Vegetable Mould through the Action of Worms (1881).djvu/223

 there was a layer of yellow clay of very unequal thickness between two beds of débris, the lower one of which rested on a floor with tesseræ. The old broken walls appear sometimes to have been roughly cut down to a uniform level, so as to serve as the foundations of 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 tesseræ 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 tesseræ. 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.