Marshy region on the river Eridanus, which had originated from a southern arm of the Padus (Po) in the period of Early History and had dried up in the Roman period. The fossil river bed was used in the construction of the fossa Augusta , the navigable canal between Padus and Classis which was the port for Ravenna (cf. Plin. HN 3,119). P. is associated with the myth of Phaethon and Cycnus  (Diod. Sic.5,23,3).
L. Gambi, Cosa era la Padusa, 1950
G. Uggeri, La Romanizzazione dell'antico Delta Padano, 1975, 49
Id., Insediamenti, viab…