Watchiing brief during construction of a new gas main trench, c.0.6.m deep. The S half of the trench cut through what appeared to be the remains of at least one Roman building, ie, foundation, floors a ?pila stack presumably in situ with hypocaust. Floor or floors comprised a layer of mortar with makeup of Kentish Rag. It may have been a plain mortar floor or basis for tessellated or mosaic pavements. The trench in Sir Isaacs Walk appeared to cut modern backfilled service trenches but still contained a high proportion of yellowish brown sandy loam and gravel, probably redeposited material from the Roman rampart behind the town wall. <1>