This strengthening work was rendered necessary owing to earthquake shocks which occurred, and possibly from the fact that the originally defective foundations on the south side of the crypt caused a slight settlement.
It may be noted here that the masons' marks found in the triforium on the Norman work are also found in the crypt on the later strengthening work, and not upon the Early Norman work. This fact has been considered to prove that the crypt was built by Aldred.
The first chapel—i.e. that below St. Andrew's Chapel—contains a double piscina with a shelf in good preservation. There are remains of hinge-posts (two sets), and the holes for the movable bar with which the doors could be fastened.
The second chapel—i.e. that underneath St. Philip's Chapel—contains an arcade of five plain arches with ornament above. There is also a double piscina with shelf in good preservation, and a large altar-step, 6 feet 2 inches by 4 feet.
The third or eastern chapel, which is under the vestibule leading into the Lady Chapel, contains portions of the building which have had to be replaced by recent work, and some fragments of tombstones, one bearing the inscription Gilbertus.
PLAN OF THE CRYPT.
From a Drawing by F. S. Waller, F.R.I.B.A.
The dark tint on the walls represents the Early Norman Crypt.
The second period of Norman work is shown by the double lines round the small shafts at A A, which denote masonry erected some time after, to carry the ribs which strengthen the vaulting.