A small trench measuring approximately 1.3 x 0.6m in area was dug to a depth of 0.8m at the rear of the town wall. The trench was located about 1m to the south of the entrance to the southern guardroom of the Balkerne Gate. The purpose of the trench was to obtain samples of the white deposits which are frequently found on the face of the wall where it is well preserved. The rear face did prove to be well preserved. Eight courses were exposed in the trench: four of tile over four of septaria, and with the mortar joints picked out with lines made with the tip of a pointing trowel, as seen elsewhere (ie Roman Colchester, ??). <1>