Immediately before the S front of the temple and castle, 59ft from the latter and 92ft from the presumed face of the former, was uncovered a large well dressed stone in the centre of which was a round hole 6.5" in diameter. The stone covered the corner of a vaulted drain and the hole must have been provided for an iron grille or the end of a pipe. The drain itself had been completely robbed from a point c.5ft S of the stone. The general appearance of the drain was not in keeping with early Roman work but the alignment with the main building is almost perfect. The position of the stone indicates perhaps a Roman surface level. The drain is 18-20" wide, the floor of tile partly plastered over - plastering was not observed in other drains in Colchester and is more characteristic of water conduits. The E arm was traced on a course parallel to the S face of the temple, 68ft in length. Where the vault was preserved the drain was quite empty - it contained no silt and no remains other than one fragment of mortarium rim - late C1 to early C2 in date. The form of the drain and other considerations prompted the search for an altar - the single trench dug to locate this uncovered the NE angle of a massive rectangular foundation of rough stones and mortar. <1>