Gier: Durèze + Bozançon
The 'La Fontane' tunnel shows a unique failing in its kind in the Lyon aqueducts. As distinct from usual where the channel has been built and vaulted without interruptions, at the place where both working-gangs met (R) the rocks were uncovered over several meters. Both groups, working in opposite directions from the manholes on, rejoin by a rude switch-crossing, so without masonry.