A HISTORY OF DERBYSHIRE Roman military works, the angles of plotting were not strict right angles, and the opposite sides are therefore not mathematically parallel. The fort was defended by a stone wall 6 feet thick, faced with courses of gritstone and filled inside with rubble and concrete in the usual Roman fashion (fig. 12.) In the middle of the two shorter sides and near the middle of the two longer ones were the four gateways not yet excavated. The west corner of the fort and presumably each of the other corners contained a turret. What manner of fosse encircled the rampart is unknown. Y 1 1 I I -I T- S T E P S c S^J r > u A ' PLAN .-v^._ . .....>l,. ... ... '-> i OF FEET FIG. 10. PLAN AND SECTION OF SUNK CHAMBER OR VAULT IN THE FORT AT BROUGH. (Derbyshire Archaokgcal Journal?) Of the interior little has been uncovered. We know only the outline and one detail of the central building or headquarters. This building was found in 1903 to be an oblong, though not quite mathema- tically rectangular, and to measure, roughly, 60 feet by 85 feet. Its back wall showed traces of two periods of building. Of its internal arrange- ments only one part has been examined. This is a sunk pit or vault, 204
