SU 1403 represents a large accumulation of quarry debris. The layer is composed almost entirely of tufo fragments ranging in size from small gravel (diam. 3cm) to large partially formed blocks (eg 40x20x20cm). Many blocks are very angular and a very few contain visible tool marks (see photos). The larger contained very little soil, suggesting that it was deposited relatively quickly, with very little time for silt accumulation.The layer is very large and could not be fully exposed due to time constraints. It fills a cut through layer SU1404 and the bedrock to the east and through layer SU1389 on the west. The bedrock underneath the debris to the west exhibits what may be cutting related to quarrying but it seems likely that the quarry faces proper existed to the north, in an unexcavated area up slope. A major north-south road lies 2m to the east, aligned with the edge of our debris, which may have been in use at the same time. Further to the north along this road lies the quarry discovered in 2009. Feasibly, the debris may have come from there.