If this is where in the crypt I think it is, could this pit be the suggested final resting place of the bones of St Paulinus (d. 10 October 644)? Originally buried in the first Saxon church at Rochester, his remains were transferred to the new Norman cathedral by bishop Gundulf who intended to house the saints bones in a separate eastward projecting shrine behind the high altar. When the east end of the cathedral was added to, and lengthened, the old east end was removed leaving its foundations preserved beneath the present crypt floor to be found first by W.H. St. John Hope in the late nineteenth century and to a greater extent during the reflooring of the crypt in more recent years.