I had another and still better opportunity of examining the nature of the foundation wall in March, 1898, at the western side of Collier Street, where, for the erection of a small coalyard, the northern wall was longitudinally laid open on the inner (intra-castral) side for a length of 38 feet, and 4 feet deep (see section). On its more eastern side, we have a layer of 22 inches Roman mortar, and 20 inches big, roundish sandstone, bound together by brown cement (specimen kept), which seems to have been poured between and over the various layers of stones. On the western side the order changes, and we have four layers of soft, decomposed rubble, separated by layers of middle-sized boulder stones; below, 6 inches to 7 inches, stiff, greenish, sometimes drab coloured boulder clay with boulder stones imbedded, the foundation resting here on greenish marshy clay. At the base, little flat pieces, or chips, of sandstone flags have been laid down. In the central part, at the bottom, for the space of 72 inches, are placed regular oblong and dressed blocks of red sandstone and millstone grit, of various length, varying from 19 inches by 10 inches to 24 inches by 12 inches. In all probability it formed the northern gate. Under the wall, at a spot marked x on the section, I discovered a great number of promiscuous land shells and bones of the newt, which must have been carried hither by some rain floods or the current of an ancient rill. These objects will be described in the appendix. In the various sections along the northern wall no pounded or broken tiles were discoverable in the mortar.
At trench No. 3 the thickness of the foundation walls varied from 5 feet to 6 feet, east of Collier Street it measured 7 feet.
It is evident from the above description that there exists
