`  :: Wait. You first said that ``Troyano's book states that two arches at the Alconetar site are original (spans 6m and 7m)``, but now you write that ``his text and captions imply that the arch on the left is an original Roman arch and the other two are more recent``. In that case, the bridge would not be a Roman segmental arch bridge at all, wouldn't it?   :: Did Troyano somewhere write that the wooden low span/rise ratio bridges of the Romans also constitute segmental arches (despite their superstructure being out of wood, not stone)?  `