of Agricola's forts between the Forth and Clyde some strategic line further to the south, including Newstead, was held until increasing pressure from the north, or an uprising in the rear, rendered a further retreat necessary.
It must at the same time be admitted that any impression of the length of an occupation based largely on the quantity of the relics left behind may easily be erroneous. The relative strength of the garrison in the two periods is an important factor which has to be reckoned with. A large force concentrated on a site for a comparatively short period would leave a comparatively large deposit of refuse behind. A sudden abandonment would also tend to increase the quantity of relics remaining on the ground, and that some disaster terminated the early period at Newstead seems probable. It is difficult to account for the presence of many of the objects found in the early rubbish pits, except on the hypothesis that they were concealed on the eve of a hurried evacuation.
Passing from the early period, we would fain distinguish the exact phase in the evolution of the fort which marks the reoccupation of Newstead after its abandonment. There need be little doubt that the later period coincides generally with the Antonine occupation. Its pottery belongs to a distinct period of Roman activity in Scotland. The same potters supplied the ware used alike at Newstead and in the forts of the Vallum; decorated bowls in the style of Cinnamus and Divixtus were common in both. And in both we have the occurrence of the stamps of the same potters, who can be definitely assigned to the second century.
The phase in the evolution of the fort, which it seems safe to assign to the later period, is the reduction in its size at the beginning of the fourth occupation. It also seems safe to assume that the cutting down of the West Annexe belongs to the same time. A coin of Hadrian came from the bottom of the inner ditch covering the Bath buildings; the pottery found in it was entirely of the later period. But the reduction in size can hardly have marked the beginning of the Antonine period. Pottery of the later period was lying in the upper levels of the pit in the Baths, but beneath the cobble foundation of the rampart that passed above it; and the rampart obviously belongs to the same period as the ditch beside it. It would therefore follow that the beginning of the Antonine occupation preceded the reduction in the size of the fort, and that it coincided with the phase which has been termed the third occupation, in which the overlapping ditches in front of the gates were filled up, but in which the entrance from the south was still on the
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