The western chapel has, at its north-western corner, a stair-way leading to three cryptal chambers whose flooring is the solid rock.
=The Sacristy.=--The building on the south side of the choir, which is generally known as the "sacristy," is a very interesting part of the cathedral. Professor Willis decided that it was erected at the same time as the original Early English choir, and no doubt it belongs to the same period. A careful inspection, however, especially of the entrance from the "minstrel gallery" to the chapel of St. Chad's Head, which now forms the top storey, shows unmistakable signs that, like the entrance to the vestibule in the corresponding bay of the north choir aisle, this doorway was once a window, similar, no doubt, to those two still remaining--one in each aisle--which look into the aisles of the transepts. This being so, it is obvious that the "sacristy," or, at any rate, the upper storey, was an afterthought, and that it is later, though perhaps only a little, than the choir, its date corresponding perhaps with that of the south transept.
The upper storey, which until recently was used as the muniment room, was originally the chapel of St. Chad's Head. It has now been restored as a chapel through the zeal and munificence of the present dean, Dr Luckock, and was re-dedicated and re-opened on St. Chad's Day, March 2nd of this year, 1897. In the order of service of that day the dean gave an account of the chapel as follows:--