Note 746 — CANTO XXIX.
James Romanes Sibbald translation
The long ridge: One of the ribs of rock which, like the spokes of a wheel, ran from the periphery to the centre of Malebolge, rising into arches as they crossed each successive Bolgia. The utmost brink is the inner bank of the Tenth and last Bolgia. To the edge of this moat they descend, bearing as usual to the left hand.