The several courses of opus quadratum which were found a few years ago, and are at the east entrance to the Corso built into the wall of a lumber store, are continued also inside that wall, and seem to be the remains of a gate tower.
See page 28. This gap in the wall is still another proof for the gate, for it was down the road, which was paved, that the water ran after rainstorms, if at no other time.
This gate is very prettily named by Cecconi, Spiegazione de Numeri, Map facing page 1: l'antica Porta di San Martino chiusa.