would have had its entrance close to the new western gate, and would not have been in its proper central position. The north and south gates, and with them the line of the Via Principalis, were accordingly moved further towards the east, and we may safely infer that with this change of gates the Principia underwent alteration and was turned round. In its reduced form, the interior plan of the fort, with its comparatively small Retentura, must have resembled that of Wiesbaden.

As already noted, the alterations within the Principia had convinced us that the building had faced the east during two separate occupations. The facts ascertained regarding the wall reducing the size of the fort gave further confirmation to this opinion, because clearly the period of the construction of the reducing wall, which must have necessitated the turning round of the Principia, was followed by a period in which the wall was removed. Not only were its gate towers buried beneath the gravel road of the final occupation, but the wall itself had been utilised for the foundation of the front wall of Block XX, while buildings and drains of later construction lay in the area which had formerly been abandoned. In fact, the change in the direction of the Principia, at first adopted through pressure of necessity to suit the altered size of the fort, was continued when the fort was again enlarged. This was probably due to a natural desire to simplify building operations, for the method of foundation employed in the later occupation lent itself readily to reconstruction on the old lines. The trench carried down to the subsoil, with its large river stones laid in puddled clay, formed a base indestructible by fire or weather, and so long as the outline and size of the building remained the same, the foundation might be used for several successive rebuildings.

Unfortunately at Newstead the demolition had been so complete that with a single exception doorways were entirely obliterated, and with them many details which would have rendered it more easy to follow the various reconstructions. But certain points were clear. The north buttressed building showed evidence of rebuilding on an old foundation. Heavy blocks of river stone embedded in clay served to support inferior masonry in which were a broken quern stone of Niedermendig lava, bricks, and other old material. It was interesting to compare this with the remains of the south buttressed building in which, although the foundations were the same, the superstructure was of well-built hammer-dressed sandstone. No doubt the size and number of those storehouse buildings were always proportionate to the extent of the garrison. Consequently, with the abandonment of the original Praetentura one