Diagonal segmental ribs

Banister F. Fletcher

Peterborough Cathedral

Source: A History of Architecture on the Comparative Method (5th ed), plate 112G (p. 285)

In England the raising of the diagonal rib, which produced the domical vault employed on the Continent, seems to have been but little used, and the method was either (a) to make diagonal ribs segmental, as in the aisles at Peterborough Cathedral; or (b) to make the diagonal ribs semicircular and stilt the springing of the transverse and longitudinal ribs. [p. 286]