Tower C lays about about four hundred feet North of Tower B, and is a totally different structure. The early 13th century towers were simpler round towers, whilst this tower is square, open to the rear, and a much later addition to the abbey's precinct defences.
Above. Tower C looking North towards Bootham.
Comparing this tower with others elsewhere on the City walls, it's possible to date it to around 1318. The huge arrow slits, three in total, fit into this time frame.
The tower projects about ten feet from the face of the wall. Unfortunately the tower backs onto private property, so it wasn't possible to inspect the interior. The tower was restored in 1952.