impossible to get away from the assumption that Gundulf built the castle in which archbishop William afterwards erected the keep. I believe that Mr. J. T. Irvine, who has kindly allowed me the use of his valuable notes on Rochester, was the first to recognize its early-Norman character and date. His local knowledge is extensive and his authority decisive on this point. The herringbone style of building is the chief characteristic of early-Norman walling in this neighbourhood. There are two distinct kinds. In one kind the faces of a wall are built in courses, every course consisting chiefly of rag-stones laid aslant in either direction, and including also a few stones large enough to fill the course when laid on their proper bed. The castle-wall is of this kind; so also is Gundulf's tower and a part of the wall of the north aisle of the cathedral. In the other kind the faces are built up of similar courses of herringbone work alternating with narrow bonding-courses of flat rag-stones: the narrow courses often decrease in width and run into flat bonding-courses, and vice versa the flat courses change to larger courses of herringbone work. The walls of St. Leonard's Tower at Malling and a portion of the wall of the south aisle of the nave of the cathedral are built in this way. There is a bit of similar walling at the end of Mr. Rae Martin's garden in the Precinct. Sketches of examples of both kinds of early-Norman wall-facing are given in the Illustrations.*

Mr. Irvine has called attention to a special peculiarity of the castle-wall: at intervals it seems to be strengthened by "internal buttresses built flush with the face of the wall." These so-called buttresses consist simply of stones of unusually large size inserted in the courses of herringbone work. There is much irregularity in their disposition, and they seem to be used wherever the line of the wall makes a slight angle. This peculiarity may be seen in the wall overlooking the river. The thickness of the wall at its base is about 41 feet, at the top 2 feet. Its outer face is plain, while the

Plate I., Nos. 1 and 2, and Plate II.

† Plate I., No. 1. In this sketch, made from careful measurements, is seen the method of strengthening the wall by the use of large stones.